Robert A. Freitas Jr., Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, First Edition, Xenology Research Institute, Sacramento, CA, 1979;

(c) 1979 Robert A. Freitas Jr. All Rights Reserved.




Chapter 20.  Xenosociology

"Frequently consider the connection of all things in the universe and their relation to one another."
          -- - Marcus Aurelius Antoninus (121-180), from Meditations

"We humans fight best in armies, gregariously, where the risk is reduced; but we generally disapprove of murderers, and of almost all private combat. With the great cats, it would have been just the other way around. As a matter of fact, few of us delight in really serious fighting. We do love to bicker; and we box and knock each other around, to exhibit our strength; but few normal simians are keen about bloodshed and killing -- we do it in war only because of patriotism, revenge, duty, glory.

"A feline civilization would have cared nothing for duty or glory, but they would have taken a far higher pleasure in gore. If a planet of super-cat-men could look down upon ours, they would not know which to think was the most amazing: the way we tamely live, five million or so in a city, with only a few police to keep us quiet (while we commit only one or two murders a day, and hardly have a respectable number of brawls); or the way great armies of us are trained to fight, not liking it much, and yet doing more killing in wartime and shedding more blood than even the fiercest lion on his cruelest days."
          -- Clarence Day, in This Simian World (1936)76

"...we may be unable to convey to him what human emotions such as anger or love mean to us. Perhaps he will be able to follow our explanation in an intellectual way but be unable to feel or identify with experiences that for us are deep-seated."
          -- Ronald Bracewell, in The Galactic Club (1975)80

"For three years, twelve hours a day, five days a week, approximately ten months of each year, I lived the life of an extraterrestrial. I began to study human behavior from an alien point of view. I was becoming alienated, and I didn’t realize it."
          -- Leonard Nimoy (1975)1939


Xenosociology, very broadly, is the study of alien social systems. Besides the general issue of social evolution on other worlds, xenosociologists must also study the development of alien psychology (including aggressive behaviors, motivations, emotions and personality), mating systems and modes of parental care, the emergence of early technologies, and various social evolutionary questions such as the origin of agriculture and the possibility of stateless societies elsewhere in the Galaxy.

Despite the fascinating character of such issues, the xenosociological literature is surprisingly sparse. Worse, much that has been written is superficial or poorly thought out. There appear to be two fundamental reasons for this deficit.

First, the human social sciences today are in a comparatively early phase of development. Until very recently, sociological research tended to proceed along specialized and anecdotal rather than generalized and systematic lines. But a general, synthetic science of culture is exactly what we need to place xenosociology on a firm theoretical footing.

Second, sociological truths are largely statistical. Given certain specified biological and environmental conditions, we cannot predict with certainty the exact societal form which may emerge. Social systems are far too complex, too interrelated, too randomized to admit of any straight forward prognostications.

In view of these difficulties, and the vastness of the universe of all social possibilities, no attempt will be made in this short chapter to integrate the full matrix of physiological, psychological, sociological and environmental combinations. The permutations of cause and effect are numerous,2957 and deserve at least an entire book to themselves. Rather, we seek here only to lay the foundations of basic xenosociological theory.

Today, a whole new generation of "cultural determinists" -- the sociobiologists -- has adopted the position that there exist basic natural forces which guide the evolution of psychology and society on any world.* Sociobiologists believe that behavior, as well as biology, undergoes natural selection. But where genes directly control body morphology, their influence on behavior is far more subtle and plastic. Each species, say the sociobiologists, is predisposed to exhibit certain general behaviors such as emotionality, aggressiveness, sociability, and so forth. This means that an alien race, given a particular environment and biology, will be restricted to certain general classes of social behavior. To use a rather fanciful analogy, genes can tell you which stadium to attend but not the rules of football that will be used nor which teams will be playing.

So where do we start? According to the Hypothesis of Mediocrity, most alien life will originate on a planetary surface. Prior to the introduction of advanced technology, extraterrestrial biological evolution, behavioral patterns and primitive technologies will be strongly influenced by the immediate planetary environment. Sociobiologists see the prime movers of early social evolution as of two kinds: Genetic and ecological.565 For this reason, xenosociologists find it necessary to examine the bases of biological evolution and ecological factors to fully comprehend the nature of alien minds and societies.


* See especially Barash,3333 Caplan,3328 Dawkins,2322 and Wilson.565,3198



20.1  Biological Evolution

From the "viewpoint" of living organisms at the level of the species, biological evolution must be regarded as a predominantly divergent process. The injection of a few members of a given type of lifeforms into a virgin environment normally results in an explosive "adaptive radiation." Species rapidly multiply to fill all possible available niches.

From the "viewpoint" of the whole environment, however, evolution is primarily convergent. Though there are many exceptions, the general rule is that species evolving in roughly similar environments tend to find similar solutions to similar problems of survival.

For instance, the deep-sea niche (where high speed may be required to feed on fast-swimming prey) has given rise to a striking example of parallel evolution. The large, streamlined "fishy" shape has evolved independently at least four times on Earth: The mosasaur (an extinct Cretaceous marine lizard), the ichthyosaur (an extinct Jurassic sharklike reptile), the tuna (and other modern fishes, including sharks), and the cetaceans (modern mammals, including dolphins).

Examples abound. Ants and termites belong to different insect orders, yet they have evolved similar societal and architectural forms. Marsupial "psuedomamnals" evolved independently in Australia and South America, filling niches identical to those occupied elsewhere by their physiological cousins the mammals. In earlier chapters we discussed the convergent evolution of legs, wings, eyes and other bodily organs. It is probably safe to conclude that "anytime you get extensive convergence of evolution along different lines you must be dealing with an almost certain process."22

Based on their observations of convergent evolution in similar environments, human zoologists and paleontologists have proposed a number of evolutionary "laws". These "laws" appear generally true on Earth, and may be expected to have some measure of applicability to extraterrestrial lifeforms as well. Here are a few of the author’s favorites:

1. The total biomass of the entire system tends to increase and become maximized over time. (Lotka’s Rule)

2. The general process of evolution involves the development of new organ systems, increasing complexity, and greater efficiency.

3. Progressively more modern forms tend to have fewer, more specialized segments and appendages. (Williston’s Law)

4. Species tend to evolve to larger sizes. (Cope’s Law)

5. Major evolutionary steps, once taken, are never reversed. (Dollo’s Law)

6. Allied races of warm-blooded animals tend to be larger in colder climatic regions. (Bergmann’s Rule)

7. Mammals inhabiting tropical regions tend to have shorter and less woolly coats than related lifeforms in colder climatic regions.

8. Herbivores have hooves; carnivores have claws. (Cuvier’s Law)

9. Limbs and tails of related species are shorter in colder climatic regions. (Allen’s Rule)

10. Organisms living in warm, humid areas tend to be more heavily pigmented than related species living in cool, dry regions. (Gloger’s Rule)

Examples of this sort can be multiplied indefinitely. Dr. Bernhard Rensch lists more than 100 such "laws" of evolution, to illustrate his thesis that "evolution is largely a lawful process, and with regard to the effect of continuous mutation and natural selection it is also a determinate process."2897

There is one other general rule of evolution, often ignored but of major significance nevertheless: Species tend to become extinct. This simple truth is rarely appreciated fully. It is a fact that more than 99% of all species that have ever trod the Earth are now extinct. While more than 3,000,000 species are alive today, more than a billion animal and plant species have arisen at one time or another in Earth’s past.624,2440 Most evolutionary experiments prove to be dead ends or are insufficiently adaptive to changing conditions. Extinction, not survival, is the general rule.1668


20.1.1  Evolution Rates

How fast does evolution occur on other worlds?

At least three different "rates of evolution" have been studied by Earthly zoologists. First there is the "morphological rate" -- the speed at which the size and shape of organisms belonging to a given species evolves over time. For instance, it has been shown that the average dimensions of horses’ teeth have increased at a rate of about 0.1% per 1000 years.440 Another measure of the velocity of evolution is the "taxonomic rate." As shown in Table 20.1, the taxonomic evolution rate measures how fast new subspecies, species, genera, and so forth arise naturally. Finally, the "genetic rate" of evolution specifies the speed at which alterations in genes are occurring in the subject population. Measured genetic rates generally confirm the values given in Table 20.1.*


Table 20.1 Average Taxonomic Evolution Rate, in Millions of Years per Unit of Taxonomic Classification
(after Rensch449)













0.1 - 10

0.001 - 0.1






















A wide variety of different factors operate collectively to increase or decrease the rate of evolution of species on any given planet. It is true that modern geneticists recognize evolution is primarily a function of genetic variation stored in the species’ general gene pool. Evolution advances by reshuffling previously accumulated gene types by a process known as "recombination." (See the discussion of the benefits of sexual reproduction in Chapter 12.) Nevertheless, the primary and ultimate source of all genetic variation is mutation.3208 If the mutation rate is too low little variability is retained, leaving a smaller inventory of possible adaptations for natural selection to act upon in response to environmental changes. If the mutation rate is too high, desirable characteristics are mutated away or are selected out before they have a chance to be assimilated into the gene pool. Thus there exists an optimum range of mutation rates for any class of organisms.305

The average background level of radiation at the Earth’s surface is about 0.12 roentgens/year. About one-third of this is cosmic rays from space. The other two-thirds comes from terrestrial sources such as natural crustal radioactivity and deposits of potassium-40 in our bodies.390 What effect on the mutation rate -- and on evolution -- does this background radiation have? Among smaller organisms, often as much as 100-1000 times the background is required just to double the natural mutation rate. Among larger organisms, as little as 3-10 times above background may produce a similar effect over the whole body. It would appear that on Earth today natural radiation accounts for only a small fraction of all spontaneous mutations.

The situation may have been much different in the past. I.S. Shklovskii and V.I. Krassovskii, two distinguished Russian astrophysicists, have calculated that Earth may have passed within 10 parsecs of a supernova event perhaps a dozen times since its formation 4.6 eons ago. In each case, the scientists believe, the intensity of cosmic radiation must have risen at least by a factor of 30. This should have caused an increase of one order of magnitude in the natural background, which would at least double the mutation rate (and so the maximum rate of evolution) for the largest creatures on Earth. The effects could have persisted for more than 10,000 years.20

Extraterrestrial creatures inhabiting a planet in the outer Core regions of the Galaxy should experience such a supernova event far more often -- perhaps once every 10 million years. Over the course of geological history more than 500 local supernovae might occur. This would double mutation rates at regular intervals and keep the pace of evolution high -- especially during the very early stages in the evolution of life on the planet when gene inventories were still small. We might hypothesize that species "turnover rates" may be significantly higher near Core regions than in the Disk of the Galaxy.

Many other factors may influence the rate of evolution on other worlds. For example, stellar class of the primary sun may be important. The hottest stars for which habitable planets are thought to exist are the F5 suns. These objects radiate more strongly in the blue part of the spectrum than our Sol, emitting about four times as much ultraviolet radiation. Because of this, many xenologists suspect that the early evolution of alien life on a world circling such a star should be considerably faster than on the primitive Earth. More energy could penetrate the oceanic surfaces, creating more complex nutrients faster and thus speeding the origin of life. F5 suns will also have stronger solar winds, which may lead to increased atmospheric ionization and greater climatic variability (and hasten evolution as well).

Higher UV levels near F5 stars may also delay the appearance of land plants.1013 Since more of these rays must be filtered out by an ozone layer which necessarily must be thicker than Earth’s, sea plants of other worlds must wait longer than their cousins on Earth for the atmospheric oxygen content (which yields ozone) to build up. If the alien planet has small or shallow seas, then the total marine biomass may be too small. In such cases, oxygen would remain scarce, a sufficient ozone layer might never be built up, and land might never be colonized by plants. The larger the planet, however, the less likely is this catastrophe. All else being equal, larger planets have higher gravity and more compact atmospheres, which means a higher rate of ozone production. In either case, marine evolution should be comparatively rapid.

In contrast, K- and M-class stars peak in the red portion of the spectrum, emitting only 1-10% as much ultraviolet as Sol. This tremendous deficit should slow or greatly retard prebiotic evolution and the origin of life because less energy is available at the surface of the primitive planet for chemical synthesis. Tidal locking is more likely in habitable zones around K- and M-stars; if locking occurs the environment could become quite severe (though relatively uniform), which will also tend to retard evolution. Finally, the UV deficit may forestall the dissipation of the primeval hydrogen/helium transsolar atmosphere. In such a system, even the innermost worlds might remain large, gaseous, and quite jovian.376 In this case, then, evolution may proceed more slowly.

Another factor which may quicken the pace of evolution is the presence of moons. By raising tides on the planetary shores, natural satellites may assist chemical mixing and catalysis during the early phases of prebiotic evolution in alien seas. Several xenologists have even suggested that mechanical wave motion may encourage and accelerate the invasion of the land by primitive plant and animal lifeforms.2362 An interesting variation on this theme occurs when the alien planet is itself a moon -- perhaps a super-jovian orbiter. While tidal locking will leave it a one-face world, the severely mutagenic radiations (such as exist near Jupiter) should provide ample genetic variation for selective forces to work with.

Planetary factors may also have a decisive effect on the rate of evolution. Perhaps the most influential of these is the relation between land mass distribution and the diversity of species -- a part of the science of biogeography. Biogeographers have discovered what they call the Species-Area Rule.1713 Mathematically, the Rule may be stated as follows: S = kA0.27, where S is the total number of species present in a land area of A square meters. (k is some constant, see below.)

In plain English, the Species-Area Rule says that, all else being equal, the number of different species present on any land mass is proportional to the area of that land mass. More land means more species; less land means fewer species. Thus, the rate of evolution is indirectly correlated with land area, since the production of more species requires "faster" evolution.

The Species-Area Rule has another interesting feature. It predicts that the same land area, fragmented into pieces, can support more total species than the original.

Take Earth as an example. If we assume there are 2 million animal species (a low estimate), distributed over 6 continents with a land area totalling 1.48 x 1014 meter2, then the constant k = 80.7 for Earth. Now suppose that the continents were broken into 100 pieces. With a hundred separate island continents, having the same total land area as before, Earth theoretically could support as many as 15,600,000 species -- more than a 7-fold increase.

Let’s try the Rule in the other direction. Today we have 6 continents and 450 taxonomic Families (such as the cat family, the dog family, the frog family, and so forth). But 225 million years ago there was only one global continent -- Pangea -- and only 146 Families. Using the Species-Area Rule, we would predict that Pangea could support 122 Families. By eliminating the modern continent of Antarctica (which is comparatively lifeless), the Rule predicts 139 Families, which is surprisingly good agreement with the paleontological data.

Why does the Rule work so well? One explanation is that the fragmentation of land masses provides a greater number of more heterogeneous environments for development. A variety of isolated habitats provides shelter from competition, and specialization may accelerate. The same land, linked together without barriers, permits competition and tends to eradicate specialized niches. Xenologists expect that the Species-Area Rule should be applicable in some general way to extraterrestrial ecologies located elsewhere in the Galaxy.

Another influential planetary factor is ecological complexity. Structurally complex habitats usually can support a wider diversity of species and thus a higher rate of evolution. This observation helps to explain the existence of "latitude gradients" in species diversity.286 That is, more species are found in equatorial tropical regions on Earth -- where habitats are more plentiful -- than in temperate or northern climes, where niches are comparatively few. Similarly, a fluctuating unstable environment favors the survival of "generalized", species with high adaptability (and presumably higher intelligence as well), whereas stable barrierless environments produce slower evolution and favor the survival of "specialized" species.1712

There are many other planetary factors which may affect the rate of evolution. For instance, smaller planets generally may have higher mutation rates because the levels of background radiation should be higher. There are various reasons for this. First, a diminutive world may experience less intense gravitational fractionation of rocky materials during its formation. Thus the proportion of heavy minerals (including radionuclides) should be higher in the crust. Also, and especially if it condensed in the solar nebula far from the central star, the planet may have a smaller metal-poor core and thus a weaker magnetic field.2876 With less shielding from the solar wind, flares, and cosmic particles generally, the level of mutagenic radiation reaching the surface will be higher and evolution may proceed at an accelerated rate.214

Another major factor that is often overlooked is planetary surface temperature. For any given biochemical basis, the reactions involved in life chemistry should proceed at faster rates on warm worlds than on colder ones.1132,1171 But life processes also depend upon the complexity of molecular structures. As a general rule, chemical species are more stable and more complex at lower temperatures.75 Xenologists who have considered the problem believe that life of a given biochemical type will tend to evolve faster on hot worlds, but will be more complex on cold worlds. Presumably the faster evolution rate may be sufficient to compensate the lack of biochemical stability on hot planets, and vice versa. Says astronomer Michael W. Ovenden:

On a planet near a star the potentialities of life are restricted, but those that exist are realized in a short time; on a planet a long way from its star, the potentialities are greater, but the rate of development and evolution is very much slower.75

(Note: The effects of higher planetary surface pressure are biochemically similar to the aforementioned effects of elevated temperature.)

In addition to prebiotic and early biotic evolution, planetary temperature may also significantly affect the rate of evolution of macroscopic animal life. For example, consider a world where the emergence of life from the sea has been swift and warm-blooded species have evolved. A hot environment will selectively favor smaller lifeforms, whose high surface-to-volume ratio helps to slough off excess heat. Further, since the planet is hot, presumably more energy is available to drive the ecology (see below). More biomass can therefore be supported; since animals are generally smaller the total population will be large. Large populations can store more variability in the gene pool (all else being equal), and mutant traits are more likely to accumulate in single individuals. Hence, the rate of evolution should be somewhat faster. Finally, evolution should proceed even faster on large hot worlds, since the greater planetary surface area permits a bigger population to be sustained.29

On the other hand, a generally cold environment should selectively favor larger lifeforms,603 whose low surface-to-volume ratio helps to retain body heat more effectively. Colder worlds should have less energetic ecologies, so less total biomass can be sustained. Since less biomass must be apportioned amongst generally larger creatures, the population should be small and evolution comparatively slow (especially on smaller worlds with reduced land areas).718,440


* Change in gene frequency per generation Dq = v + q(s-v-u) - q2s, where q is the frequency with which the gene occurs in the original population, q + Dq is the gene frequency in the next generation, s is the gene’s selective advantage, v is the mutation rate favoring the gene, and u is the mutation rate opposing the gene.1709 Subspecies often differ by only a single gene. The most reason able choices are v = u = 10-6 (unstable genes may have spontaneous mutation rates as low as 10-2, but 10-5-10-6 is more usual) and s = 10-3 (e.g., 0.1% more of those organisms possessing the new gene will survive than those without it). If the frequency of the new gene is to increase from q = 1% up to q = 99% in the general population, about 9,200 generations will be required (about 10,000-100,000 years for most mammals.



20.2  Xenopsychology

Knowledge of the fundamentals of alien psychology is a "must" in any first contact or culture contact situation. No real comprehension of ET societies is possible without a thorough understanding of the differences between human and alien motivations, goals, and behavioral repertoires. The field of xenopsychology is quite broad, encompassing issues of motives and drives, need hierarchies and goal-directed behavior, personality and "ego" (or "selfness"), perception, subjective time, sleep, circadian rhythms and other natural bodily cycles, "instinct," learning, habituation and conditioning, language, memory, emotions, altruism,3331 awareness, and so forth.1941 Unfortunately, it is beyond the scope of this book to deal with all of these fascinating areas in detail. Consequently the emphasis here will be upon the most immediately relevant basics.

We have already discovered that the environment is intimately involved in the process and rate of natural genetic evolution. Xenopsychologists, following modern sociobiologists, believe that a species’ surroundings also shape and direct the evolution of its gross behavioral patterns. Perhaps the single most critical environmental parameter is available bioenergy.


20.2.1  Energy Ecology

The psychology of sentient extraterrestrials is closely intertwined with the details of the local ecology. But the most fundamental global ecological factor is energy. A more energetic environment normally can support either a larger number of similar-sized creatures or a similar number of larger-sized creatures. We know that all organisms require energy to survive, and that on most worlds virtually all of this must come from the local sun. In a sense, the star "feeds" the planetary inhabitants.

How much bioenergy is available to drive a global ecosystem? Clearly the first factors to consider are planet type and biochemistry type. Jovian planets and terrestrials will differ in the energy available to their native lifeforms. (These planetological problems are dealt with in chapters 4 and 5 in some detail, and will not be repeated here.) Also, cold ammonia-solvent lifeforms may require less energy to maintain than a similar population of hot liquid-sulfur creatures.

But assuming a terrestrial Earthlike world and a biocarbon biota, we begin our analysis by noting that the total energy available at the top of the atmosphere should be about 2 x 1017 watts. About 90% of this is lost due to reflection, absorption and direct conversion to heat, or because it consists of unusable infrared radiation. The remaining 10% is available for photosynthesis -- about 2 x 1016 watts.

The theoretical maximum efficiency for the chemical conversion of photon energy into organic matter (food) is about 36%.3220 However, the net observed efficiency of Earthly chlorophyllic plants generally runs from 1-5% in the field. The global average is even lower -- about 0.2% -- since the large open oceans are essentially lifeless aqueous deserts.48 While other worlds may evolve more efficient photochemistries, or have a larger biologically active land area, it is doubtful that the 0.2% rating will be much improved by natural evolution alone. So, in the case of Earth, this leaves 4 x 1013 watts.

The energy pyramid (also "food chain" or "food web") shown in Table 20.2 illustrates how ecologies are powered by sunlight.3221 At the base of the pyramid are the "primary producers" of food -- on Earth, the green plants. These producers are eaten by "primary consumers," or herbivores. The herbivores, in turn, are eaten by carnivores, who them selves are eaten by still larger carnivores. Ecologists customarily refer to each successive stage of predation as a "trophic level." Thus plants are at the first trophic level, the smallest carnivores at the third trophic level, etc.


Table 20.2 Energy Flow at Various Trophic Levels in the Terrestrial Food Chain



Sample Annual
Biomass Maintenance

Energy Budget
for Maintenance



1 Man

80 watts


Middle Carnivores
(Tertiary consumers)


800 watts


Small Carnivores
(Secondary Consumers)


8000 watts


(Primary Consumers)


80,000 watts


(Primary Producers)

1000 tons

800,000 watts


The Energy Pyramid (Figure 20.1) describes the flow of useful bioenergy through an ecological system. Plants are eaten by herbivores, which in turn are eaten by higher-level carnivores. Typical food chains have 3-5 stages, called ‘trophic levels." Only about 10% of the latent bioenergy in each level is passed along to the next -- about 90% is wasted as heat or in respiration.

Omnivores, such as humans, may eat at all consumer levels. This permits larger populations to be supported. If men ate frogs instead of trout in the above example, 30 people could be supported. If he ate grasshoppers, 900 people could live. If he could consume grass, 2000 persons would survive.997


Figure 20.1 The Energy Pyramid


Also, in ecology there is something called the Diversity-Stability Rule: Ecosystem stability tends to be correlated with food web complexity. The four equal-population food web structures shown in Figure 20.2 illustrate various possibilities. In (A), there are too few herbivores; in (B), too few carnivores. Predators and prey are too specialized in (C), which consists of simple linear food chains. Because of the multiplicity of intertrophic links in (D), it has the greatest potential for adaptive stability.297

Alpine and polar environments tend to have fewer links and less stability, while tropical and oceanic environments are generally more stable.


Figure 20.2 Illustrations of the Diversity-Stability Rule


Experiments conducted in a wide range of different environments have measured ecological efficiency -- the energy gained by an organism when it eats a member of the next lowest trophic level. A good rule of thumb is that at each level 90% of the available bioenergy is lost. Only 10%, on the average, is passed along to consumers at the next highest level. Due to the staggering amount of waste, few ecosystems on this planet have more than five trophic levels. Xenologists expect these generalizations to hold true for extraterrestrial ecologies as well.

As Table 20.3 demonstrates, the effects of limited bioenergy on size of population are striking. If all humans were purely herbivorous, Earth theoretically could support 50 billion of them. But if people tap into the food web as Level-5 carnivores (e.g., man eats trout, trout eat frogs, frogs eat grasshoppers, and grasshoppers eat grass), the terrestrial ecology could support only 50 million humans worldwide. If this happened, each person would have to patrol a home range (personally or by proxy) of about 10 km2 in order to find his daily meal.*


Table 20.3 Maximum Supportable Large-Organism Population
in a Typical Terrestrial Global Ecology (Earth)

Trophic Level



Maximum Supportable
Population of 70 kg
Warmblooded Animals




(e.g., ~100-watt humans)




 4 x 1013




4 x 1012




Carnivores I

4 x 1011




Carnivores II

4 x 1010




Carnivores III

4 x 109




Similar bioenergy assays may be made of smaller ecosystems, say, on the continental, regional, or local levels. But the conclusions are almost always the same: Herbivores maintain the highest population densities and the smallest home ranges, while carnivores are usually fewest in numbers and utilize the largest home ranges. Omnivores, who can tap into the food web at any trophic level beneath, fall somewhere in between. They are the most versatile and adaptive, and thus most likely to survive in both the best and worst of times.

Xenopsychologists are interested in these results for a number of reasons. The motives, instincts, and personality traits of a sentient ET are likely to be strongly influenced by its hereditary feeding habits. An herbivorous race might be more socially-minded and less disposed to kill or commit acts of overt physical aggression. An intelligent carnivorous race might instinctively live in rather small groups, and value individuality and personal courage above all else.** A species with a large home range tends to be solitary and "antisocial."

Of equally great importance is the fundamental lesson of environmental finiteness. This turns out to be one of the central driving forces behind all animal and sentient behavior -- whether psychological, social, or political. It is easy to see why this is so.

All lifeforms that dwell on planets, regardless of their shape, size, or biochemistry, must "consume negentropy" to live. This requires a flux of energy. But if biological order and information are to increase -- a process which most xenologists regard as the basic "goal" of life -- then energy flow through the total ecosystem must also increase.

But planetary bioenergy is strictly limited. The natural supply of usable energy will be in short supply on any world.

Scarcity is inevitable.


* The population density of human beings on Earth today ranges from 0.0003 km2/person in Hong Kong to 1.0 km2/person in Mongolia, with a worldwide average of about 0.04 km2/person. Humanity, it would appear, is already herbivorous (trophic level 2, on global average).

** Except where large herbivores have evolved without an associated predator (e.g., elephants, 0.3 km2/animal1725), carnivores are normally larger than herbivores because a predator must be more powerful than its prey. Larger bodies can support larger brains, and predation is a more active lifestyle than grazing and thus requires more alertness; xenologists expect carnivores to be more intelligent as a general rule. This conclusion has been tentatively confirmed by modern paleoneurologists.2910



20.2.2  Competition and Aggression

Among lifeforms that engage in reproductive activities, the crisis of ecological scarcity manifests itself as population pressure (a special case of the more general problem of "biomass pressure," which affects reproducers and nonreproducers alike). The evolutionary drive to increase order and decrease entropy, among reproducing species, normally involves the production of offspring. The crisis arrives when there is no longer enough bioenergy to sustain these offspring (it may be local, regional, or global in extent). Most commonly, the limiting physical resource is food.

There are at least six different ways by which population pressure may be partially or wholly relieved in nature:

          1. Natural modification of the environment (drought/flood cycles, volcanoes, earthquakes, ice ages)

          2. Disease and malnutrition

          3. Predation by higher-level consumers (overabundance of prey may attract more predators)

          4. Emigration (especially useful in homogeneous barrierless environments, such as the sea)

          5. Competition (among species at the same trophic level)

          6. Technology (artificial modification of the environment)

The list is arranged in a kind of natural hierarchy. Successful use of one method obviates the need for others below it. For instance, if environmental changeability or disease are sufficient to raise the death rate equal to the birth rate in a given species, then predation probably will not play a major role. Or, if predation is severe enough to relieve population pressure, then emigration and competition may not be necessary. The most sophisticated pressure-reduction technique -- technology -- may be viewed as a method of last resort.

Furthermore, the last four methods on the list are active strategies. They are largely under the control of the lifeform, rather than the random forces of the environment, and so may evolve as part of the psychology of an alien race. That is, predatory, emigratory, competitive, or technologic "instincts" or predispositions may be "learned" by a species over periods of evolutionary time.

For example, cats raised in isolation will chase and kill rats even though they’ve never seen a rodent before (instinctual predation). Lemming migrations and bee swarming apparently demonstrate the existence of some genetically preprogrammed flocking behavior keyed to population density (instinctual emigration). Mating ceremonies involving ritual combat between males, as among stags, illustrate a predisposition to controlled aggression (instinctual competition). The human hand is preadapted for easy manipulation of tools, and ants, termites and bees automatically build hills, nests and hives according to precise -- and genetically predetermined -- specifications (instinctual technology). Depending upon the situation, extraterrestrial species may incorporate any of these active behavioral strategies into the basic psychology of the race.* A fine example in science fiction is the "engineer" subrace of the alien Moties (in Niven and Pournelle’s The Mote in God’s Eye.668), whose members clearly display an instinctual technologic sense from birth. And since any one strategy may not be completely effective by itself, ET psychologies may consist of hodgepodge combinations of two or more methods which, taken together, do work.

While any method or combination of methods of relieving the problem of population pressure may give rise to equally complex behavioral repertoires, a complete treatment of all possibilities is clearly beyond the scope of this book. In order to reduce the task to manageable proportions, we shall consider here, briefly, only one of the methods in more detail: Competition.

The term "competition," as used by xenopsychologists and sociobiologists, has a very specific meaning: The active demand by two or more individuals, either of the same species (intraspecies competition) or of two or more species at the same trophic level (interspecies competition), for a common resource or necessity of life that is actually or potentially limited.565 Competition reduces population pressure by reallocating scarce energy resources among the stronger or more intelligent organisms, and, more indirectly, serves to apportion or limit the supply of reproductive mates.

Extraterrestrial races may manifest their competitive urges in a wide variety of different behaviors. These need not necessarily include "aggression" (first or unprovoked attack, assault, invasion, fight, or other hostile encroachment). For instance, sentient ETs may engage in "scrambling," a non-aggressive form of competition that involves "getting there first," The idea is to outperform all competitors while avoiding direct confrontation.

Another kind of nonaggressive competition is called "repulsion." Using this technique, Pharaoh’s ant (Monomoriun pharaonis) is an unusually effective competitor with nearby species for local food sites. Arriving at the site, colony members release a potent chemical substance from their poison glands and spread it around the entire food collection area. The horrible odor, to which Pharaoh’s ants are inured, repels all intruders.2933 Repulsion behavior has been discovered in other Earthly species. If a recently impregnated female mouse is placed with a new male of a different strain than the first suitor, she will usually abort the fetus spontaneously and become sexually receptive again. The aborting stimulus is a pheromone produced in male urine that is sniffed by the female, activating her pituitary gland and corpora lutea.2932 Similarly, a male-to-male inhibitory pheromone is used by male armyworm moths (Psuedaletia unipuncta) to ward off sexual competitors.3218 Extraterrestrials, too, may prefer repulsion to direct aggression. Chemical repulsion may be used, but any means of accosting the senses may be employed -- ultrasound, bright light, vibrations, etc.

Nevertheless, on this planet and doubtless many others the dominant forms of competition do entail physical aggression in varying degrees of intensity. Among the most common forms of aggressive competition are "territoriality," "dominance," and "fighting." Note that these behaviors, though distinct, are not mutually exclusive: A territory may be defended by a social group with an internal dominance order maintained by ritualized fighting. But each alien species may have its own unique blend of these three and possibly other forms of aggression. (Any social structure maintained or controlled by direct physical confrontation between individuals may be considered aggressive.)

Territoriality is the defense of a certain resource-containing area, by an individual or group, against intruders. Dominance is the establishment of a scarce resource distribution hierarchy within a single social group, based on "power" (physical strength, cunning, wealth, or whatever). Both techniques reduce the need for fighting (which injures the group) while achieving the same results as continuous raw physical aggression. On Earth, both are widespread among the vertebrates and among invertebrates with more highly evolved and larger body sizes (chiefly crustaceans and social insects).

Xenopsychologists, with modern sociobiologists, believe that such behaviors similarly will be common, though by no means universal, among extraterrestrial races genetically predisposed toward aggressive reaction. Species on many worlds may never turn to competition and aggression to solve the problem of biomass pressure. But among those that do, many will choose territoriality or dominance behavior, or both, to regulate the severity and social costs of fighting.

What determines the choice? Unfortunately, sociobiology is yet a infant science. We don’t have all the answers. Sociobiologists are fairly certain that the local characteristics of the environment may significantly tip the balance one way or the other. According to two researchers:

When important resources are distributed uniformly in space, there is little opportunity for resource monopolization. If the resources are sufficiently abundant and stable through time, territoriality typically occurs. When important resources are highly clumped, the possibility arises for a small percentage of the population to monopolize a large proportion of the available resources. {e.g., dominance/distribution chains}2918

But we must keep in mind that the "choice" is genetic, not volitional, Basic patterns and predispositions of behavior evolve because they are more adaptive for the species as a whole in the struggle to survive. For instance, consider the sociobiological explanation of herding behavior. It appears that herding, flocking and schooling are genetically preprogrammed tendencies, by which the group avoids predation by utilizing marginal individuals as a living shield against danger. Says Wilson:

Since predators tend to seize the first individual they encounter, there is a great advantage for each individual to press toward the center of its group. The result in evolution would be a "herd instinct" that centripetally collapses populations into local aggregations....Centripetal movement generates not only herds of cattle but also fish and squid schools, bird flocks, heronries, gulleries, terneries, locust swarms, and many other kinds of elementary motion groups and nesting associations.565

Similarly, xenopsychologists believe that extraterrestrial races evolutionarily will "choose" territoriality, dominance, fighting, etc. based on survivability criteria determined by the local environment.** These generalized behavior patterns, once fixed in the alien species’ gene pool, will remain permanent fixtures of the creatures’ psychology. They may decrease in importance with increasing sentience but, at least until the ET race discovers bioneering or some equivalent technology, the primitive urges and predispositions will remain:

The cultural evolution of aggression appears to be guided jointly by the following three forces: (1) genetic predisposition toward learning some form of communal aggression {among species having such predisposition}; (2) the necessities imposed by the environment in which the society finds itself; and (3) the previous history of the group, which biases it toward the adoption of one cultural innovation as opposed to another. To return to metaphor, the society undergoing cultural evolution can be said to be moving down the slope of a very long developmental landscape. The channels of formalized aggression are deep; culture is likely to turn into one or the other but not to avoid them completely. These channels are shaped by interaction between the genetic predisposition to learn aggressive responses and the physical properties of the home range that favor particular forms of the responses. Society is influenced to take a particular direction by idiosyncratic features of its pre-existing culture.3198

Which alien species are most likely to carry a genetic predisposition toward aggressive behavior? Researches into the patterns of Earthly lifeforms have yielded a few tantalizing clues. For example, aggression is more common among carnivores than among herbivores or omnivores, and it is also more intensely expressed. Also, field studies have shown that aggression is more likely among species inhabiting stable ecosystems than among those populating unstable ecosystems. (Stable environments, all else equal, are more likely to require competition to regulate population pressure.) Further, aggression should increase when food is clumped rather than scattered, allowing domination of food or food-bearing land to become profitable.565 Finally, combative interactions in most aggressive animal species peak during the breeding season -- usually among males during the female estrus.1830 Sexually reproducing species may be more aggressive. Continuous estrus (as among humans) leads to continuous sexual competition, but at lower intensity.

So aggression is not necessarily, as is often said, a bad thing. It is simply one of many highly useful survival-oriented evolutionarily fashioned behavioral adaptations. And we may be in for a few real surprises. As Nobelist Konrad Lorenz once suggested, personal bonding and individual friendships are found "only in animals with highly developed intraspecies aggression, never among peaceable herd creatures, . . .perhaps by way of ritualization of a redirected attack or threatening."455 While modern sociobiologists challenge such categorical conclusions, xenopsychologists today recognize that the very concept of friendship may not be nearly as universal as was once thought.2913


*Social traits can evolve relatively quickly, as fast as 10-100 generations. This is because differential mortality rates can reach 10% or higher in certain natural settings (selective advantage s = 0.1). According to Dr. E.O. Wilson, well-known Harvard sociobiologist, single-gene substitution can be mostly completed in 10 generations. Wholly new behavioral patterns -- the honeybee waggle dance, human speech, etc. -- will normally require from 1000-10,000 generations to evolve.565

** Population-density-dependent or "spectrum" responses are extremely common adaptations on Earth. For example, free-living wolves are mostly pack-territorial with little social ranking. Crowded into a zoo with plenty of food but little territory, dominance hierarchies quickly emerge. Wilson offers a more complex (but hypothetical) instance in a single species:

At low population densities, all aggressive behavior is suspended. At moderate densities, it takes a mild form such as intermittent territorial defense. At high densities, territorial defense is sharp, while some joint occupancy of land is also permitted under the regime of dominance hierarchies. Finally, at extremely high densities, the system may break down almost completely, transforming the pattern of aggressive encounters into homosexuality, cannibalism, and other symptoms of "social pathology."565



20.2.3  Universal Emotions

Emotions play an extremely important role in human psychology. These powerful reactions to external stimuli often help to motivate or activate aggression, sexual activity, learning and perception, and a wide variety of other behaviors. These simple facts suggest many questions to xenopsychologists. Will ETs be more or less emotionally motivated than humans? Will their reactions differ markedly from our own? Will they have emotions foreign to us, and vice versa? Are there any "universal emotions" that must be common to most, if not all, sentient races in the universe?

But first we must decide exactly what we mean by "emotion." There is widespread disagreement on the definition, but one of the more useful versions by Magda Arnold draws a careful distinction between emotional states and emotional behaviors. According to Arnold’s theory, emotional experience proceeds in several sequential stages:

1. Perception and Appraisal -- External stimulus is perceived, then judged to be good, bad, useful, harmful, etc. (mostly based on learned associations).

2. Emotion -- An internal state of arousal or "feeling" arises, involving physiological effects.

3. Action -- The organism, motivated by emotion, engages in some specific behavior (approach, avoidance, attack, feeding) depending on the intensity of the response, learned behavior patterns, and the countervailing or reinforcing nature of other motives that may simultaneously be present.

We see that emotion is an internal state, not a behavior or a perception of external reality.

While there may exist a few "universally frightening" stimuli involving sensory overloads (loud noises, bright lights), research on mammal emotionality has demonstrated that the perception and appraisal of potentially emotional stimuli is mostly learned rather than preprogrammed by evolution. Similarly, humans are taught to express their emotions in behaviors that are socially and culturally acceptable. The strong cognitive element in both appraisal and action argue against universality, especially in view of the widespread divergence in human perception and behavior.

We can say little about Arnold’s stages (1) and (3) regarding alien sentients because of the tremendous malleability of these two factors. Without knowledge of the environment, physiology, or culture, it is difficult to understand ET behavior.* For all we know, an extraterrestrial may be aroused by the wink of an eye or a loud cough; its response thereto may include violent physical attack, knotting of the tentacles, or a well-aimed emesis of the stomach contents in the direction of the disturbance -- whatever is considered appropriate in its culture.

What about the phenomenon of emotion itself? Recent sociobiological and neurological evidence strongly supports the notion that the seat of emotion is the limbic portion of the brain. On Earth, emotion appears only among vertebrates possessing emergent or developed limbic brain systems.2542,56 (See Chapter 14.) But why should it have evolved at all?

Modern sociobiologists believe that to understand emotion it is necessary to focus on genes rather than individuals or species. In other words, the basic process of natural selection is not survival of the fittest person or species, but rather the survival of the fittest genes. Both emotionality and behavior thus evolve as strategies to maximize the spread of genes.565,3176 In the sociobiological view, species always evolve behaviors which best serve to propagate their genes in succeeding generations.

Emotions may perhaps be regarded as "instinctual" behavior transducers, taking information (on maximizing gene survival) accumulated by the species through selection and adaptation, and dumping it into the current response structure of the individual. Says sociobiologist Wilson:

The hypothalamic-limbic complex of a highly social species such as man, "knows," or more precisely it has been programmed to perform as if it knows, that its underlying genes will be proliferated maximally only if it orchestrates behavioral responses that bring into play an efficient mixture of personal survival, reproduction, and altruism. Consequently, the centers of the complex tax the conscious mind with ambivalences whenever the organism encounters stressful situations. Love joins hate; aggression, fear; expansiveness, withdrawal; and so on; in blends designed not to promote the happiness and survival of the individual, but to favor the maximum transmission of the controlling genes.565

Dr. Irven DeVore, another Harvard sociobiologist, in a recent interview put it this way:

Millennia of evolution have equipped you with a whole complex of motivations, inclinations, propensities, emotions -- what we call proximate mechanisms -- that guide your behavior appropriately. The fact that love, friendship, anger, or jealousy usually occur when they have adaptive consequences is not to belittle these emotions. The individual might even be aware of the ultimate causes that underlie his behavior, but the whole point is that while these emotions are authentic, they also serve the interests of one’s genes. Various aspects of these systems might be quite conscious, for example, the mother scheming to arrange the best marriage for her daughter. But in most instances, the sources of these emotions are beyond the limits of our ordinary awareness. What counts is that we are left with emotions -- love, friendship, gratitude -- that are expressions of our deepest biological nature, entirely natural and adaptive... . Each will occur in conditions that are adaptive from the point of view of the genes someone bears.2946

Emotion, in other words, permits every individual to display an instinctual wisdom accumulated by the species over millions of years of evolution.

Of course, extraterrestrial sentients may possess physiological states corresponding to limbic-like emotions that have no direct analog in human experience. Alien species, having evolved under a different set of environmental constraints than we, should also have a different but equally adaptive emotional repertoire. Countless recipes may be cooked up using just a dash of imagination.

For example, assume that human observers land on an alien planet and discover an intelligent animal with an acute sense of absolute humidity and absolute air pressure. For this creature, there may exist an emotional state corresponding to an unfavorable change in the weather. Physiologically, this emotion could be mediated by the ET equivalent of the human limbic system; it might arise following the secretion of certain strength-enhancing and libido-arousing hormones into the alien’s bloodstream in response to the perceived change in weather. Immediately our creature begins to engage in a variety of learned and socially-approved, behaviors, including furious burrowing and building, smearing tree sap over its pelt, several different territorial defense ceremonies, and vigorous polygamous copulations with nearby females -- apparently (to humans) for no reason at all. Would we interpret this as madness? Or love? Lust? Fear? Anger? None of these is correct, of course.

The alien is feeling badweather.

While xenopsychologists suspect that even emotional sentients may not share similar emotions, they are far more certain that no "universal emotions" exist among all extraterrestrial sentients generally -- because intelligence simply does not require it. Intelligent aliens, in other words, may be emotionless.

Probably the smartest nonemotional creature on Earth today is the octopus. The animal sports eight suckered but dexterous tentacles, color-and texture-variable skin, and a highly educable intelligence.2899,2908 An invertebrate mollusc, the octopus has an advanced ganglionic nervous system. Of the total 500 million nerve cells (5% as many as a human brain), 300 million are distributed in the arms and 200 million are collected in the central ganglic brain. (As usual for invertebrates on Earth, the brain has managed to wrap itself nooselike around the creature’s throat during the course of evolution.)2901

The octopus does have a few minor endocrine systems. For instance the optic gland, which apparently activates according to daylength, controls the maturation of sexual organs and the onset of sexual behavior. At least seven other glandular structures have been tentatively identified which control body fluids, maternal behavior, etc. Even so, compulsory hormonal and physiological emotional responses appear to be absent in the octopus. The animal is, from the strict mammalian viewpoint, utterly without emotion.

Xenopsychologists find octopus behavior both fascinating and instructive. It is a solitary animal with no social inclinations whatsoever. Worse, it is also a carnivore, so it’s even more difficult to imagine a large society of the creatures. Each individual is fiercely independent; when crowded into a small tank, they will fight and establish a dominance hierarchy.2901

Octopuses have no fear of fire and are insensitive to burns.2900 The animal knows sex, but doesn’t get very excited about it. The heartbeat of a male octopus in the midst of copulation is as steady as in a resting animal. The sexual displays of males during courtship appear to serve only for identification, never for stimulation, of the female.2911

Broods are enormous impersonal affairs -- up to 250,000 eggs in a batch. No maternal love is lavished on offspring after birth; the young must fight for their own lives. Females often fast themselves to death guarding their own unhatched eggs. An octopus has no "childhood."

The creature may not know what it means to feel hungry. Mammals long deprived of food become excited and venture out in an agitated search for food. The response of the octopus to food deprivation is totally different and utterly alien. When crabs become scarce, octopuses resign themselves to long watchful inactivity until the day the supply improves. They become lesslikely to emerge from their houses attack possible prey passing by.2911 Motivation is not as adjustable as in mammals, yet octopus behavior under stress is considerably more "cool and calculating." After hundreds of hours of direct observation, undersea explorer Jacques Cousteau had this to say:

The octopus is a timid animal. Far from attacking a diver, its first reaction is to flee, to hide. But its timidity is a reasoned reaction, one that is based primarily on prudence and caution. It is not an instinctive and groundless fear that persists regardless of circumstances.2900

Octopus mentality seems to be oriented toward calculated prudence, more plastic than reptiles and more aloof than mammals. Is this, perhaps, a clue to the possible behavior of intelligent emotionless extraterrestrials?


* Science fiction writers have had a field day imagining strange behaviors in strange environments. In Hal Clement’s Mission of Gravity, we expect the aliens to exhibit rather pronounced fears of heights, walls, ceilings and falls, since the maximum planetary surface gravity is 700 gees and even short drops could be fatal.2069 A world which enjoys 2000 years of continuous daylight before it is plunged into a brief nightfall could be expected to engender panic reactions during the unaccustomed darkness.2920 Wasting water on a barren arid world may cause an angry response from the natives.2919



20.2.4  Xenophobia

The sight of a stranger can provoke some of the strongest aggressive responses among Earthly animals. Wilson claims that the xenophobic reaction has been documented in almost every species showing a high form of social organization, vertebrates and invertebrates alike:

Male lions, normally the more lethargic adults of the prides, are jerked to attention and commence savage rounds of roaring when strange males come into view. And nothing in the day-to-day social life of an ant colony, no matter how stressful, activates the group like the introduction of a few alien workers.565

Competition and aggression are generally more intense within a species than between different species. Still, forced into close proximity, grossly different animals become nervous and uneasy -- especially if the one bears a reasonable resemblance to an established fear-object (say, a predator) of the other. Zoologists sometimes attribute this to a kind of universal wariness between creatures differing substantially in physical appearance. Wilson admits: "In the primitive lexicon of the emotive centers, strange means dangerous."565 Adds another writer:

Interacting with a creature that is unfamiliar is anxiety-provoking. Its reactions, motivations, and desires cannot be assumed to be the same as one’s own, and therefore its behavior cannot be predicted. A movement that would not provoke anxiety when made by a friend or even a casual acquaintance can provoke an extreme response when made by a stranger. Given that situations involving unknown quantities are inherently anxiety provoking, it is relatively easy to understand how actions can be interpreted to mean something quite different from what the person who performed the act intended.222

Or, as yet another expresses it:

The mind of man is stocked to the gunwales with emotional parochialisms. Very few men would be self-controlled enough to extend courtesy to a horse-sized scorpion who was the master of another world, even if it were prudent to do so, even if the scorpion were venomless and exhibited the manners of a Spanish duke."1550

Such gross physical differences may give rise to more subtle difficulties as well. Consider a meeting between a human being and an intelligent crablike creature. Among humans, the open-fisted handwave is an almost universal sign of greeting.2552 The handshake, perhaps a display of cultural origin intended to demonstrate a lack of offensive weapons, is similarly universal among human societies. So when a man sees the crab, he gives his favorite greeting.

But consider the crab’s point of view. To it, claws are the main weapons of offense. The raising and lowering of claws, as well as any similar vertical or arclike waving motions, are characteristic threat gestures among many terrestrial crustacean species.2926 To the intelligent crab, the human handwave may be interpreted as an invitation to attack, a sign that the man is of hostile intent and is asking for a fight. The creature may oblige by attacking. Conversely, what if the crab is angry at us? Its clawwaving threat display might be interpreted by untutored humans as a friendly handwaving gesture of greeting. When the alien is approached peaceably, the ensuing attack by the mad crab may be regarded as treachery or slyness rather than a simple cultural difference between the two species (Figure 20.3).


Figure 20.3 Claw-Waving Threat Displays In Crabs

Among crabs, claws arc the main weapons of defense and offense. Claw motions have been ritualized as characteristic threat displays. At left are the clawwaves of a variety of fiddler crabs, including Uca rhizophorae (vertical waving), (b) Uca annulipes (lateral waving), (c) Uca pugilator (circular wave with outstretched claw), (d) Dotilla blanford (double clawwave), and (e) Goniopsis cruentata, or the mangrove crab (complex double clawwave)2827 Below are a few more examples of fiddler crab waving. The lateral-waving Fuji Island crab pulls its claw in initially (a), stretches it out in a sideways move ment (b), raises it high above the head (c), then returns it along an arc to the original position (d). Variations on vertical waving are shown in the sequences of the Malayan fiddler crab (e & f) and of the Philippine fiddler crab (g & h).2926


Besides displays, a wide variety of behavioral "releasers" may render more difficult all attempts at cross-species communication and understanding, and make xenophobia more likely.2578,2442 Again, one example will serve to make the point. According to Konrad Lorenz, human beings have a rather strong set of instinctual "brood care releasers" (Figure 20.4). Depending upon a variety of physical characteristics a lifeform possesses -- large head, rounded body shape, short thick extremities, and so forth -- people will find it to be "cute" and experience a strong desire to pick it up, cuddle and fondle it. This particular human releaser has been demonstrated repeatedly in various experimental situations.2923,2924 Such feeling on our part toward the sentient aliens with whom we are dealing could result in behavior which is at best inappropriate and, at worst, fatal.


Figure 20.4 Releasers in Human Beings

Konrad Lorenz has suggested that behavior patterns of caring for young are released in humans by a number of cues which characterize infants. These "brood care releasers" include:

  1. Head large in proportion to the body.

  2. Protruding forehead large in proportion to rest of face.

  3. Large eyes below the midline of the total head.

  4. Short, thick extremities.

  5. Rounded body shape.

  6. Soft, elastic body surfaces,

  7. Round, protruding cheeks.

  8. Specific behavioral cues such as clumsiness.

The figures at LEFT illustrate the "baby schema" of human brood care behavior. In the leftmost drawings are head proportions of animal forms generally considered to be "cute"; the rightmost drawings are the adult forms of the same animals, which do not release the drive to care for young.2922

BELOW Lorenz also believes that humans have other releasers which affect attitudes towards other creatures. Below are shown the head of a camel (left) and an eagle (right). Lorenz claims that man has an innate releasing mechanism that responds to the relative position of the camel’s eyes and its nose. In man, this particular combination means "an arrogant turning away," so we consider the camel to be an aloof and arrogant animal. In the eagle the bony ridge above the eyes is viewed as a wrinkling of the forehead; together with the pulled-back corners of the mouth, the eagle’s expression is seen as "proud decisiveness" and daring. Unfortunately, these interpretations of the psychology of our fellow lifeforms have little or nothing to do with the actual mood of the particular animal involved.2925


Xenopsychologists believe that xenophobic reactions cut across species, genus, and even phylum lines. Wariness of strangers is extremely common among the animals of Earth. So while we may be repulsed by the physical appearance of intelligent snakes, lobsters, and squid from other worlds, of one thing we may be almost certain: We will appear just as ugly to them.



20.3  Early Technological Civilizations

Technology, or the artificial modification of the biosphere, is a unique method for achieving balance between population pressure and ecological forces. As suggested earlier, it may be used as a population reducing technique. However, the most important sociological function of technology is to increase production. This is of critical importance in alien social evolution, Xenosociologists believe there are at least four fundamental requirements for the evolution of a technological civilization on a planet bustling with lifeforms:

1. Motivation or behavioral predisposition to use tools;
2. Manipulatory organs preadapted for tool-using;
3. Sufficient physical resources to build technology; and
4. Sufficient energy to power the technology.

High individual intelligence is not a fundamental requirement. Ants, bees, termites and other social insects have evolved technologies such as architecture, carpentry, dairy farming, and the domestication of other animals for "equestrian" purposes565 without advanced personal sentience. Great intelligence is certainly an enormous asset in the creation of a technical civilization, but it is not essential.

Early technological cultures may arise in any of three planetary environments: Telluric civilization (land), aquatic civilization (sea), or avian civilization (air).


20.3.1  Telluric Civilizations

All human societies of which we are aware have been land-based. They also have all been found on Earth. How common are telluric civilizations throughout the rest of the Galaxy?

The first requirement is motivation. On this planet -- a typically exotic world -- examples abound. Ant lions and worm lions knock insect prey into their capture pits by hurling sand with the head. Termites build structures on the order of 100 "stories" high, and ants maintain flocks of dairy aphids which are milked regularly. Beavers build dams and dome-shaped lodges. Primates display a wide variety of tool-using behavior -- sticks are used for whips, clubs, spears, anthill fishing poles, toothbrushes, and as levers to pry open boxes, fruits, or nuts; leaves are used as drinking and feeding tools; and so forth.565 Tool-using behavior seems widespread among land-living species on Earth.

The second requirement (manipulators) is particularly easy, since ambulatory limbs which preadapt a species for tool-using are particularly suited to locomotion on land. Even the most primitive terrestrial vertebrate forms -- the amphibians -- have 5-fingered hands, two arms and two legs. Several species of lizards are known to have opposable thumbs, supposedly the hall mark of human tool manipulating ability. A few zoologists have speculated that if mankind were eradicated today it is likely that his technocultural replacement could evolve in as little as 15 million years.400 The raccoon would be one possibility, since its hands are thought by some to be superior to our own for grasping and manipulating. Pandas have evolved an alternative but satisfactory method of grasping using a thumblike appendage, and koala bears have not one but two opposable digits on their forepaws.450 Human related simian stock, such as chimpanzees and apes, might also replace us.

The third requirement is physical resources. As historian Richie Calder suggests, a technical culture can only manifest itself in the materials that are available from the physical environment:

The Eskimo, although an ingenious people and blessed with a remarkable memory, never developed beyond the Neolithic (New Stone Age) because of their very limited materials.. They had no access to ores that might have set them on the track of metallurgy; cold and snow prevented agriculture and made them hunters; they had no wood as they were beyond the tree line; and the lack of other plant life denied them fibers for weaving. Without these materials they simply were unable to evolve their own technology.968

Discussions among xenologists on the availability of technology materials frequently center upon the abundance of various metals on planetary surfaces. (See Bova,1400 Huntington and Cushing,2620 and Livesay.2723) Astronomical aspects are best considered first. For instance, most Disk stars in the Galaxy should have sufficient metallicity to permit terrestrial planetary formation provided other conditions are also favorable. Core stars generally have even higher metallicity, so the physical resource factor is even more positive for the evolution of metal-using technical civilizations. Also, the older a star the sooner it was formed from the primordial galactic nebula -- and thus the fewer heavy elements it and its worlds may possess.2876

Planets located in mid-habitable zone (of the biocarbon ecosphere) normally will show heavy element compositions roughly similar to Earth, having condensed out of the primitive solar nebula at about the same temperature.2050 While the total fraction of heavy elements varies from star to star, the relative fraction of each metal is surprisingly uniform.1945

While planetary bulk composition may stay relatively constant (in a given ecosphere around the star), there may be serious problems in surface distribution. As suggested in an earlier chapter, large worlds should have thinner crusts (which more easily buckle) and more severe tectonic activity. This activity will tend to thrust rich subcrustal heavy metal deposits to the surface, making them available for technological utilization. (Prospectors have long known that the richest mineral and ore deposits are generally found in regions of volcanic activity and in mountainous terrain.2909) Less-massive planets should have comparatively few concentrated ore deposits near the surface.

The fourth requirement for civilization is energy. Land dwellers are pretty well-off. Fibrous vegetation or animal oils can be burned, as can natural hydrocarbons tapped from pools or pockets of decaying organic matter. Fires permit smelters and the working of metal products, and the technology is on its way.*


* There may be a few unusual (to us) cases. For example, on a planet with a chlorine atmosphere heavy metals might serve as fuel. In Cl2 gas, hot strips or wires of copper, or iron wool, spontaneously burst into flames.



20.3.2  Aquatic Civilizations

Many possible variants of aquatic civilization have been named by xenosociologists. Amphibious littoral civilizations, for instance, may inhabit the seashore. Pelagic civilizations would occupy the water mass and the surface of the sea. Benthic or abyssal civilizations may live in the extreme ocean depths and sea floor of other worlds. Estuarial civilizations may make their homes in bays, fiords and river waters. Limnic cultures could live in lakes.

But are aquatic technical civilizations possible at all? There has been much written on this point, and most writers seem to have reached a negative conclusion. (See Anderson,63 Hoyle,1559 Livesay,2723 MacGowan and Ordway,600 Macvey,49 and Strong.50) But this author believes the majority is wrong.

Consider the requirement of motivation. Many water-dwelling lifeforms on Earth employ technologies (e.g., artifacts) to assist in their survival. One of the most primitive is the archer fish (Toxotes jaculatrix), which carefully aims and spits blobs of water at its prey (insects and spiders) to knock them into the water where they can be caught in the fish’s mouth. Another example, considerably more sophisticated, is the octopus. This intelligent invertebrate gathers stones, chips, and metal scraps to build small cavelike houses in which it resides. Another unusual example is the sea otter (Enhydra lutris). This semiaquatic mammal collects stones and shells from the ocean bottom. Then, while floating on its back at the surface, the otter places these objects on its stomach and uses them as anvils against which to pound and crack open mussels and other hard-shelled molluscs.565 It appears that many sea creatures on this planet are strongly motivated to try their luck at technology. If Earth is typically exotic, water worlds elsewhere in the Galaxy should fare no worse.

What about manipulators? The lack of manipulative organs in the most intelligent seagoing animals -- the cetaceans -- implies that their intelligence "cannot be worked out in technology,"1365,15 unless they have outside help. But this may just be an evolutionary fluke. Elephants seals, a genus of "returned mammals" closely related to the cetaceans, still retain the in credibly delicate, 5-digit "flipper fingers" that their cousins the dolphins must once have possessed. On another world, brains and hands may coincide.*

Of course, there is no reason why boneless tentacles could not serve as technologically useful appendages in the absence of hands and fingers. The cephalopods, which include the octopus, cuttlefish and squid, have from 8-10 limbs surrounding their mouths. These probably evolved from whiskerlike projections near the food cavities of more ancient molluscan forms. The fact that intelligent octopoids do not dominate the seas of Earth may be, again, merely an evolutionary fluke. First, octopuses have hemocyanin blood, which is less efficient than hemoglobin. The animal tires easily and has little appetite for sustained heavy labor. Second, octopuses have ganglionic nervous systems which may have limited their sentience on Earth. But there is nothing fundamentally wrong with a tentacular intelligence. The convergence with certain well-known land forms (prehensile-tailed monkeys, elephants) strongly suggests that tentacles may build technologies on other worlds.

How about physical resources? Clays and mud are available for ceramics and pottery, sand for glass, and there is a tremendous variety of organic materials available for chemical industry -- dyes, acids, drugs, etc. Stone masonry is quite possible, since concrete can be mixed that can set underwater. Nodules littering the continental shelves and ocean floors could be harvested for their nickel, cobalt and manganese. Fantastic quantities of metals are afloat in seawater itself. For example, a kilogram of iron can be harvested by filtering 50,000 m3 of ordinary seawater past a simple magnetic lodestone. (The liquid volume involved is only about as much as a single shark breathes in a month.) Marine lifeforms could devise an advanced biological technology including "cold light" streetlamps using luminiferous bacteria, architectural coral, and "slave fishes."

Where do we get the energy to work all these resources? Aquatic ETs may discover superheated underwater volcanoes -- these exist in great numbers on Earth’s ocean floors and should be even more numerous on larger, more massive pelagic worlds. Submarine oil deposits may be found in sedimentary strata. Natural gas and other combustible vapors upwelling from the planetary interior could be trapped in special containers and burned using oxygen imported from the surface. Lacking combustion, bubblewheels could be erected over regions of submarine helium gas effluence and the rotary power used to turn mechanical flywheels.

There is no bar to the full development of electrical power generation. Electric eels could be domesticated for this purpose, or simply cannibalized for their organic batteries. Alternatively, marine extraterrestrials could build their own batteries using pieces of carbon, tankards of seawater and some other electrolyte, and a small bit of metal. The electricity thus obtained might then be used to perform electrolysis on water, splitting each molecule into its constituent hydrogen and oxygen atoms. This gaseous mixture is a potent fuel, and could conceivably be used to power smelters, streetlights, seacars and seabuses, 2800 °C oxyhydrogen blowtorches, turbines and jet-propelled devices, and even rockets.

There is little that man has accomplished technologically on land that could not be repeated in some analogous fashion by a race of marine lifeforms on a pelagic world elsewhere in our Galaxy.


* It is interesting to note that cetacean intelligence soared following its return to the sea, reaching a level of "encephalization" equal to that of modern-day humans 10 million years ago.2910 There is no truth to the assertion that the sea is incapable of bringing forth high intelligence, for it was the seagoing dolphins, not humans, who first made it to the top. Ethologist John Eisenberg correctly points out that the assumption that the marine environment is homogeneous is false: "There are currents and different temperature and pressure regimes which make it very exciting."3241



20.3.3  Avian Civilizations

Almost without exception, previous writers have concluded that technological civilization among avian creatures is virtually impossible. (See Hoyle,1559 MacGowan and Ordway,600 and Strong.50) Again, the author strongly disputes this conclusion.

First of all, aerial lifeforms on Earth appear favorably disposed to tool-using. Solitary wasps (Ammophila) pound their nest entrances shut with a small pebble held in their mandibles. The woodpecker finch uses twigs, cactus spines and leaf stems to dig insects out of crevasses in tree bark. The Australian black-breasted buzzard carries rocks and lumps of soil skyward; released, the rocks fall on the eggs of other birds which break and are eaten by the buzzard. The black cockatoo of the Aru Islands grasps nuts in its beak with a leaf while cracking them open (like holding a jar in a towel for better traction while the lid is twisted off). And northern blue jays, held in captivity, have been observed tearing off strips of newspaper flooring and using them to rake in food pellets placed out of reach beyond the mesh wall of the cage.565 Extraterrestrial creatures evolving in similar aerial niches may be expected to develop similar biological predispositions.

How about manipulative appendages? Several writers have argued that when birds evolved wings they lost the use of one of their two pairs of limbs. Thus they cannot have arms or hands to work out their intelligence in technology, and so there can be no technical civilization of the air. But this line of reasoning overlooks the possibility that the ancestral form of alien avians might be, say, hexapodal. If the original reptilian stock had begun with six legs instead in four, then two could evolve into wings, two into arms, and two could remain legs. Alternatively, the "gasbag beasts" described in an earlier chapter would most likely feed from the underside, and so might evolve mouth-tentacles much like the cephalopods of Earth’s seas. Such limbs would admirably fulfill the requirement of a manipulatory organ and should permit the emergence of an ET avian technological civilization.3234

As for materials and energy, resources on the ground will probably have to be tapped because the air is practically devoid of useful minerals. Wind power and rain power are possibilities, but fire is probably much easier and will directly permit the smelting of structural and ornamental metals. Avian technology should be very similar to telluric technology generally. It is also possible that tool-using avians may be land-dwelling "returned" lifeforms, adapted to a permanently flightless existence much like the ostrich, the kiwi, and the extinct giant moa (a bipedal, bimanous 240 kg bird) of Earth.3006



20.4  Alien Social Systems

In his recent book On Human Nature,3198 sociobiologist E.O. Wilson suggests that human social behavior is best evaluated by comparison with the behavior of other major categories of Earthly species.3646 Human beings are proud of their intelligence and many cultural achievements, but seldom do they pause to consider how many of their social traits can be traced back to their primate (and mammalian) ancestry. Remarks Wilson: "The general traits of human nature appear limited and idiosyncratic when placed against the backdrop of all other living species."3198 Or, as Clarence Day pointed out many years ago in his lighthearted essay "This Simian World,"76 many of the strategies people use to cope with the environment are characteristic of our arboreal, visually-oriented, curious, manipulative, leadership-hungry, pair-bonding, verbally communicative simian forebears. Psychologically as well as physiologically, humans have a lot of monkey in them.

Wilson gives several examples. Intimate social groupings among humans usually contain on the order of 10-100 adults, never just two (as in most birds and marmosets) or up to thousands (as in many fishes and insects). Human males are generally larger than females, the result of a mild form of sexual competition common to primates and many other kinds of mammals. The young are psychologically molded by a lengthy period of social training, first by close associations with the mother and later by interaction with other children of the same age and sex. Another common feature is social play, a strongly developed activity involving role practice, mock aggression, sex practice, and exploration. These and many other properties together identify a constellation of social traits characteristic of the taxonomic group including the Old World monkeys, the great apes, and human beings. Notes Wilson:

It is inconceivable that human beings could be socialized into the radically different repertoires of other groups such as fishes, birds, antelopes, or rodents. Human beings might self-consciously imitate such arrangements, but it would be a fiction played out on a stage, would run counter to deep emotional responses and have no chance of persisting through as much as a single generation. To adopt with serious intent, even in broad outline, the social system of a nonprimate species would be insanity in the literal sense. Personalities would quickly dissolve, relationships disintegrate, and reproduction cease.3198

An exhaustive inventory of the elements of "human nature" has yet to be prepared. However, a few partial lists have been compiled. In 1945 the American anthropologist George P. Murdock listed the following root characteristics of man’s society which have been recorded virtually in every human culture known to Earthly ethnographers:

Age-grading, athletic sports, bodily adornment, calendar, cleanliness training, community organizations, cooking, cooperative labor, cosmology, courtship, dancing, decorative art, divination, division of labor, dream interpretation, education, eschatology, ethics, ethnobotany, etiquette, faith healing, family feasting, fire making, folklore, food taboos, funeral rites, games, gestures, gift giving, government, greetings, hairstyles, hospitality, housing, hygiene, incest taboos, inheritance rules, joking, kin groups, kin ship nomenclature, language, law, luck superstitions, magic, marriage, mealtimes, medicine, obstetrics, penal sanctions, personal names, population policy, postnatal care, pregnancy usages, property rights, propitiation of supernatural beings, puberty customs, religious ritual, residence rules, sexual restrictions, soul concepts, status differentiation, surgery, toolmaking, trade, visiting, weaving, and weather control.3201

After citing Murdock’s work, Wilson suggests that few if any of these properties are inevitable outcomes of either high intelligence or advanced social life; "human nature is just one hodgepodge out of many conceivable."3198 An entomologist by training, Wilson has no trouble imagining a nonhuman insectlike society whose members are even more intelligent and complexly organized than people, yet which lacks many of the qualities listed in Murdock’s inventory above. The "alien" inventory might look something like this:

Age-grading, antennal rites, body licking, calendar, cannibalism, caste determination, caste laws, colony-foundation rules, colony organization, cleanliness training, communal nurseries, cooperative labor, cosmology, courtship, division of labor, drone control, education, eschatology, ethics, etiquette, euthanasia, firemaking, food taboos, gift giving, government, greetings, grooming rituals, hospitality, housing, hygiene, incest taboos, language, larval care, law, medicine, metamorphosis rites, mutual regurgitation, nursing castes, nuptial flights, nutrient eggs, population policy, queen obeisance, residence rules, sex determination, soldier castes, sisterhoods, status differentiation, sterile workers, surgery, symbiont care, toolmaking, trade, visiting, weather control, . . .and still other activities so alien as to make mere description by our language difficult.3198

Civilization, says Wilson, is not intrinsically limited to hominoids. Only by an accident of evolution on this particular planet was it linked to the anatomy of bare-skinned, bipedal mammals and the peculiar qualities of human nature.


20.4.1  Models for Extraterrestrial Societies

While it is certainly possible that sentient ETs may also evolve from their world’s equivalent of primate stock, chances are that many if not most will not. In the absence of high technology modification, the psychological and sociological constitution of alien sentients will reflect their biological ancestry. Indeed, the time-honored science-fictional technique for generating new extraterrestrial psyches is to use various Earth animals as behavioral models.2956

While there is some scientific validity to this procedure, it must always be remembered that basic feral traits will be strongly modified by intelligence. Primitive animal drives and instincts will be "culturalized" by the sentient alien, an enormously complex process which extends from minor (redirected bare-teeth threat display becomes smile) to major (curiosity channeled into scientific research) sociocultural aspects.

For example, primates are known to be moderately aggressive animals, and all human societies retain this trait. Some societies have no institutions of mass aggression such as sports or warfare, but all display personal aggression to varying degrees. The Arapesh of New Guinea, often cited as the most striking example of culturally determined peaceability, are not without aggressive displays. The effect of culture has just been remarkably strong: Children are trained to vent their rage on objects rather than other persons, a habit that continues during adulthood.2928 Similarly, the Hopi Indians of North America suppress all physical forms of aggression and violence but still vent their feelings by trading vicious verbal insults.452

Still, employed with proper caution, the behavioral analog technique can illuminate many fascinating possibilities. Endowed with higher intellect and patterned after a variety of nonsimian ancestral forms, extraterrestrial lifeforms may have developed societies which display, articulate, or attempt to hide the ancient behavioral traits characteristic of the animal group from which the sentient race originally sprang.*

Sentient aliens derived from avian stock might exhibit behaviors more common to birds than to simians. Earth birds have response mechanisms that promote group synchronization and integration, such as call notes and visual cues, which permit flocking and body contact while in flight. There is also territoriality, pecking orders, and pair-bonding (the inclusion of the male in the role of parental care).

By contrast, mammals rarely display pair-bonding. It is generally found only among carnivores and primates. Because of the existence of mammalian milk glands and the need for prolonged care of the young, mother-child-centered societies are virtually universal among this animal order. In other words, mammalian social groups tend to be female-centered.2946 This pattern is exemplified by lions:

The core of a lion pride is a closed sisterhood of several adult females, related to one another at least as closely as cousins and associated for most or all of their lives within fixed territories passed from one generation to the next. The adult males exist as partial parasites on the females. Young males almost invariably leave the prides in which they were born, wandering either singly or in groups. When the opportunity arises these males attach themselves to a new pride, sometimes by aggressively displacing the resident males. Male bands both inside and outside the pride typically consist of brothers, or at least of individuals who have been associated through much of their lives. The pride males permit the females to lead them from one place to another, and they depend on them to hunt and kill most of the prey. Once the animal is downed, the males move in and use their superior size to push the lionesses and cubs aside and to eat their fill. Only after they have finished do the others gain full access to the prey.565

As young animals, terrestrial carnivores engage in complex play, prey-catching, and aggressive behavior. As adults many become solitary, especially those who hunt by stealth such as the cat. Aliens based on a feline model will doubtless retain a mentality and worldview characterized by solitary stealth and individual achievement. This outlook will find expression in their science, politics, warfare, and daily labors. Paul Layhausen has hinted that sentient catlike extraterrestrials who try to live together in cities may find it harder than humans do to adjust, when he writes of the effects of subjecting feline populations to unnatural conditions of crowding:

The more crowded the cage is, the less relative hierarchy there is. Eventually a despot emerges, "pariahs" appear, driven to frenzy and all kinds of neurotic behavior by continuous and pitiless attack by all others; the community turns into a spiteful mob. They all seldom relax, they never look at ease, and there is a continuous hissing, growling, and even fighting. Play stops altogether and locomotion and exercises are reduced to a minimum.2937

(Primate behavior under similar circumstances is surprisingly complacent -- in fact, the dominance hierarchies become more stable.2950)

Canids such as wolves and wild dogs hunt by cooperatively running down their prey in relatively open habitats. They live in packs of from 5-50 individuals, a social organization admirably suited to predation of larger creatures. Zoologists have found that the African wild dog exhibits a degree of cooperation and altruism unmatched in the animal kingdom save by elephants and primates. Hunters share equally in the brutal kill. Food is taken back to pups, mothers, and other adults who remained behind at the den. After the kill, juveniles are given priority in feeding, an uncommon gratuity among carnivores. Sick and crippled adults are cared for indefinitely and are rarely peremptorily abandoned.

An alien society modeled after canid behavior would be characterized by a peculiar combination of peaceful communal living and savage pack boldness. Wild dogs are generally relaxed, egalitarian, and monogamous. Litters of offspring are usually restricted to one or two females -- frequently by violent means (murder of excess pups) -- so pack females vie with one another for the privilege of nursing the pups. No individual distance is maintained, and pack members often lie together in heaps to keep warm. Just after a kill, there seems to be a competition among the hunters to see who can make the most submissive gestures. Displaying a wide, yawning grin, each individual playfully tries to burrow beneath the others in a gallant struggle to become the "underdog."565

Whiptail wallabies, Australian marsupials belonging to the same taxonomic family as the kangaroo, are strict vegetarians who inhabit grassy woodlands. One population was observed to be loosely grouped into three distinct "mobs" that remained quite stable for at least a year. Each mob had from 30-50 members, and achieved a fairly high population density -- about 0.02 km2/individual, close to the global human average -- perhaps due to the herbivorous lifestyle:

Meetings between mobs were uncommon but amicable. They resulted in a temporary fusion of the groups into single aggregations that rested and fed together. On such occasions the wallabies treated individuals belonging to other groups much as they did members of their own group. Animals of all ages mingled easily, while the adult males fought for dominance and courted females with no apparent particular reference to mob affiliation.565

Aggression is highly ritualized among these comparatively gentle animals -- even the fighting for dominance is described as "gentlemanly."

Wallaby behavior is strongly individualistic, but despite this they have produced stable aggregations ranging over fixed exclusive territories that are "owned" by a mob. Each animal is capable of personal recognition of many other individuals. Their small, 5-fingered paws are used for grasping, and, although they have no opposable thumb, it is easy to imagine a race of sentient, tool-using extraterrestrial wallabies building a mighty civilization elsewhere in our Galaxy.

The black bear provides yet another possible model for alien society.3079 These large, omnivorous mammals normally have low population densities, from 1-5 km2/individual. Society is organized around the mother. Adult females breed in feeding territories which are exclusively occupied by them. However, they also permit their daughters to share subdivisions of the maternal land, and they "bequeath" their property rights to these daughters when they move away or die. Males take no part in this system of inheritance:

They disperse from the maternal territories as subadults. During the mating season the fully mature males enter the female territories and displace one another by aggressive interactions, especially when they meet in the immediate vicinity of the females. Later, as their testosterone levels drop, they withdraw from the females and assemble in peaceful feeding aggregations wherever the richest food supplies are to be found. In the late fall they return to the female territories to den.565

Or, intelligent extraterrestrials may evolve from creatures resembling rodents. One of the more solitary of the social rodents on Earth is the beaver. This amazing mammal designs and stabilizes its own habitats with the dams and ponds it creates. Beavers are highly industrious individuals, often repairing a damaged dam overnight. They build large dome-shaped island lodges of sticks plastered with mud -- a kind of wood-reinforced earthen house bearing a striking resemblance to Navaho hogans in the American Southwest. The interior is usually a couple of meters high, large enough for a man to stand up inside. These structures are built sturdily enough to last many generations. Food caches are often stored inside.

Beavers live in pond cities of many lodges, normally with one family to a lodge. A family typically consists of a mated parental pair and two sets of offspring -- newborns and youth. The youth disperse from the parental lodges only after several years of residence there. While beavers are of placid disposition and often labor together cooperatively, their character is basically individualistic and they will defend their own lodge area against members of other families. The animal has very stable populations, since both birth and death rates are very low. Beavers today measure a meter in length and weigh 30 kilograms, but fossil forms from the Oligocene epoch exceeded 2 meters and probably weighed as much as a small adult human. With their unwebbed 5-fingered forepaws, there is no reason why evolution on another world could not have produced a sentient ET race with a behavior similar to that of the terrestrial beaver.

A lesser-known but more gregarious rodent species is the blacktail prairie dog, named for its distinctive barking voice. Living in the exposed habitats of the open plains, these small-dog-sized rodents tend to form dense local populations. It is believed that predation is the main driving force of social evolution for these creatures -- dense aggregations and a communal alarm system are substituted for the cover of rocks, foliage, and the "impregnable fortresses" such as the lodges built by beavers.

In the Black Hills of South Dakota, prairie dogs live in towns consisting of as many as 1000 individuals. These townships are physically divided by natural boundaries such as ridges, streams, or bands of vegetation into neighborhoods or "wards." Each ward consists of several burrow-homes, called "coteries" by ethologists. These are the real social units of the prairie dog community. Coteries typically comprise a group of 4 adults and 6 children, and are stable family units. Members of coteries share burrows and clearly recognize each other as close associates, "kissing" each other in greeting each time they meet.

Perhaps the most extraordinary aspect of prairie dog society is that, much like the black bear, coterie territorial limits are passed along by tradition. Burrow-homes are inherited and descend down family lineages:

The population of each coterie constantly changes over a period of a few months or years, by death, birth, and emigration. But the coterie boundary remains about the same, being learned by each prairie dog born into it. The young animals evidently acquire this information through repeated episodes of grooming from other members of the coterie along with rejection by territorial neighbors. New coteries are formed by adult males who venture into adjacent empty land and commence burrowing there. They are followed by a few adult females. The juveniles and subadults are left behind in the old burrows.565

Of course, other creatures than mammals may be conceived of as templates for social evolution. In the world of invertebrates, the societies of insects are familiar. But the social spiders are less well-known.2951 These predatory carnivores live together in "towns" numbering as many as 1000 adults. A large and elaborate central web is constructed by all the members of the community, and the giant structure is then occupied by several generations in succession.

Social spiders collaborate in capturing large prey. Both male and female attack, feeding on the catch communally. Even the young take part, swarming over the adults to seek out their own feeding place. Social information is transmitted by two-dimensional vibrations in the central webbing. While each spider lives alone, company is tolerated in close proximity during feeding. There are no caste systems. Yet intelligent ETs modeled after these creatures could hardly be considered "civilized" in the popular sense -- injured spiders, or spiders from whom the communal scent has been cleansed, are viciously attacked by their neighbors.

With a little imagination, a bewildering variety of conceivable alien behavioral patterns may be generated simply by imagining what various Earthly species would be like if only they were a bit more intelligent.


* Examples from science fiction include ETs based on insects,668 crustaceans,442 molluscs,1946 amphibians,2935,2615 reptiles,2940,3007 avians,2929 and both land2873,753 and aquatic1930 mammals.

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