1978: The physical appearance of intelligent aliens

SOURCE: Journal of the British Interplanetary Society

Vol 32, pp.99-102,1978

TITLE: THE PHYSICAL APPEARANCE OF INTELLIGENT ALIENS

AUTHOR: N.J. SPALL Bearsted, Nr. Maidstone, Kent, England

ABSTRACT

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There can be little doubt that one of the most important factors that will determine the manner in which our society reacts should contact ever be established with intelligent extraterrestrial (ET) life forms will be the physical appearance, or morphology, of the alien.

All the prejudices, the fears, the mistrust and the bigotry that exists amongst the races that make up mankind will be focussed on this reaction. Thus, speculating on the morphology of an intelligent alien is important for the future of space exploration. Serious efforts are now being made around the world in the field known as Search for Extraterrestrial Intelligence (SETI) and the manner in which our society reacts to contact will depend to a great extent on the appearance of the alien.

The anticipation of the possibilities now may reveal whether a shock for the world is likely. It is also useful to consider alien morphology in terms of gauging how likely the chances of intelligent aliens evolving really are.

1. AN APPROACH TO THE SUBJECT

The problem of trying to anticipate the physical appearance of the ET is at first sight ludicrously impossible. To start with, we don’t even know if intelligent ETs exist, let alone what their planet of origin is like or what their morphology may be.

Our task is therefore limited to using what knowledge we have of the evolution of intelligent life on Earth, considering possible extraterrestrial planetary environments and making a series of reasonable assumptions. A combination of biology, zoology, and anthropology is required as well as the newer science of exobiology. Most important, the overriding thought when considering the subject should be “how would this imagined alien become intelligent?”

2. THE TWO VIEWS

Conveniently, disagreement over the likely appearance of intelligent ETs divides itself into two opposing camps. On one side are those who take a rather anthropomorphic view of the ET and believe that it would basically be humanoid in shape with two arms, two legs, ahead at the top of the body and the main sense organs located on the head. Opposing this view are those exobiologists who believe that the intelligent ET is bound to appear exotic because the creature would inevitably have taken a totally different evolutionary path from man and would have arisen in a very un-earth like planetary environment.

This article will show, however, that the case put forward by the non-humanoid ET protagonists will not stand up to the example of the evolution of intelligent life on Earth, nor the necessities of morphology that a creature requires to become intelligent. It is therefore suggested here that any intelligent life across the galaxy will have evolved into a basically humanoid form.

3. EXOTIC BIOLOGY

A possibility often suggested by more radical exobiologists is that extraterrestrial life might depend on chemistry that does not require the carbon atom. Bracewell [1] has proposed that life could make use of the chemistry of the silicon atom rather than the carbon atom. Silicon-based organisms would, for example, breathe out silicon dioxide (sand) instead of carbon dioxide. The rock-eating creature has often been suggested as a product of this biological system. [An example of this can be seen in the STAR TREK episode about the Horta.  AB]

The problem is that silicon polymers of the protein type are unlikely to form the compounds essential for chemical evolution. Bieri [2] points out that the energy requirements for duplicating a living system are fulfilled only by carbon and the high energy phosphate bond.

It is very difficult to envisage any life other than that based on the carbon compounds forming in water. Unfortunately, this limits the planetary considerations necessary for the evolution of larger sized organisms somewhat severely — in fact, it restricts planets that may have intelligent to those with broadly Earth-like surface temperatures and pressures. (It also restricts the type of star that may shine on life producing planets — the DNA molecule is sensitive to high levels of radiation, particularly the ultraviolet.)

What of possible creatures that could get by without requiring the availability of an Earth-like oxygen-rich atmosphere? The conjectured ‘balloon‘ creatures floating in the gas belts of Jupiter and using, instead of oxygen, a metabolism of hydrogen — could they ever become intelligent ETs? And what is wrong with Fred Hoyle‘s “Black Cloud,” an intelligent gas cloud thousands of kilometers across? The answer lies in our prime question, “how could this creature become intelligent?” Intelligence, it is argued later, will probably only arise from a stimulating predatory existence in a harsh but survivable physical environment.

Conceding defeat to the necessity for life to be based on carbon in a water medium, the exotic morphology ET supporters suggest that there are enormous variations open to chance evolution even under Earth-like conditions. Slight differences in surface pressure, temperature, gravity or solar radiation, they argue, will produce widely divergent evolutionary trends [3]. Steen [4] suggests that intelligent ETs might be insect-like, bird-like, fish-like or even plant-like. They may be spherical in shape, glutinous jelly-like creatures, such as “Quatermass” might meet, or possibly even a planet-sized oceanic intelligence such as that in Stanislaw Lem’s novel “Solaris.”

For less bizarre (but still very exotic) alien creatures proposed for extraterrestrial life bearing planets, the exhibits on display at the National Air and Space Museum’s “Life in the Universe” section in Washington, DC provides some good examples of exotic aliens [5]. Biologist Bonnie Dalzell has designed for a dry Earth-like world the “hexalope,” a six legged antelope. For a high gravity planet, we are presented with the “Bandersnatch,” a monstrous herbivore with eight legs, a largemouth in its chest, two eyes on stalks and ears along the side of its body — the creature weighs 30,000 lbs. on its 3-G world! The intelligent ET that Dalzell presents us with is a six-legged toad-like creature.

Life on Earth shows us just how strange creatures can become in the chain of evolution. The giraffe is a good example of this. But it is highly unlikely that these creatures could ever become intelligent.

4. THE ANTHROPORMORPHIC VIEW

The problem ignored by exotic ET protagonists is that speculation on the morphology of the ET must take account of the lessons taught us by evolutionary development on Earth.

(The argument for humanoid ETs given here is based on the works of Robert Bieri [2], N.J. Berrill [6] and Robert Puccetti [7])

In the early period of the development of life on Earth, organic matter based on carbon compounds began in a water medium before the invasion of the land. The early sea bound creatures developed a critical characteristic that would decide the future form of land dwellers — that of bilateral symmetry in the shape of the body. This shape reduced water resistance and turbulence to a minimum and became the characteristic of all the higher creatures of the sea. It can be seen that adoption of a predatory way of marine life has developed bilaterally symmetrical creatures as diverse as the squid, the penguin, the seal, the otter, and the large fish. Radially symmetric ocean-dwelling creatures all adopt a relatively stationary way of life, jellyfish, sea anemone, etc., having a loss of sensitivity and degeneration of the nervous system when compared to the more active predators.

Bieri points out that predatory animals with complex nervous systems and bilateral symmetry possess the largest and most important sensing and grasping organs close to the mouth. Also, digestion and excretion is most convenient with an anterior mouth and posterior anus for an active hunting animal. In order to reduce time for nerve impulses to travel from the sensing organs, the brain is at the head.

5. CONCEPTUALISM AND INTELLIGENCE

Conceptualization, it would seem, can arise only in a land animal. Birds cannot possess brains large enough for this due to the fact that they must be light in weight and have hollow bones to fly. A large intelligent brain requires a considerable amount of blood and therefore a heavy cardiovascular system — both these factors would lead to an impossible power to weight ratio for an intelligent airborne creature. It is also difficult to imagine an intelligent ET evolving from gliding winged creatures such as the flying squirrel (which glides from trees with the use of membranes under its front legs) — it is too small to evolve intelligence. It is doubtful that even a gliding creature as large as the extinct Pterodactyl could ever develop a large enough brain.

The question of intelligence arising in sea animals is somewhat more complex due to the fact that the whale family happens to possess large brain capacity, a very advanced system of communication and displays remarkable feats of intelligence. However, conceptualisation, as Puccetti attempts to define it, seems to arise in conjunction with a social existence, speech and the use of tools. The development of tool usage undersea is extremely difficult due to the density and viscosity of water. Predatory sea animals rely on their natural hunting equipment — teeth, streamlining, speed, etc. — rather than weapons and tools. Only semi-land creatures, such as beavers and otters (both mammals) possess any sort of manipulating appending and these they use on the surface.

How the whale family came to develop such a large cerebral capacity tends to cast some doubt on the whole question of conceptualization development. Here it is assumed that whales are clever, but do not conceptualize their existence.

An encounter, therefore, with a race of intelligent aliens who are either aquatic, reptilian or are creatures capable of flight and who developed conceptualization characteristics with a high level of technology, seems highly unlikely. Our intelligent ETs would have to be land dwellers.

6. THE PREDATORY SUPREMACY

It should be emphasized that it seems most likely that all intelligent conceptualizing creatures in the galaxy will have their own origins in predatory animals. Man’s origins appear to stem from herbivore apes that, faced with climatic and vegetation changes, left the trees, became omnivorous and adapted to running on the savannah, hunting other animals in groups and using their ability to grasp and manipulate to develop weapons, tools and eventually a basic technology. It is difficult to imagine an animal bothering to use weapons and tools, firstly if it was a fully adapted herbivore and secondly if it was already a competent predator, such as the lion or tiger. Arthur C. Clarke describes this critical path that the early hunting apes had to take extremely well in 2001: A SPACE ODYSSEY (although of course, he did not let his apes develop their technology purely on their own initiative.)

Man has remained the only creature with technology on this planet because of his predatory hunting nature, despite the basic ingenuity of creatures such as the ant with its ingenious cities like hills, chimpanzees which can fish out termites with sticks, birds that can break shells with heavy stones, and the sea otter that can break open shells by floating on its back and beating them against stones on its chest. These creatures have stretched their manipulative abilities to the limits. [??]

7. MOVING AROUND

The development of legs, arms and grasping appendages is critical to our conceptual ET’s road to intelligence. A primitive technology will require the ability to hold and manipulate, with some degree of sensitivity, basic tools and weapons such as clubs, spears, knives and twine. The intelligent ET must have this manipulative capability combined with the speed of movement, otherwise it will remain in its comfortable environment (as did the dolphin) and we would certainly never meet it stepping out of a starship.

As a method of movement, sliding, wriggling and rolling are all much too slow for the land predator. As Puccetti points out, walking is the only viable means of moving at high speeds and for long distances. The wheel was never used as a means of locomotion by nature except in some tiny bacteria. Although the reciprocating knee joint in the human leg can put up with large shock loads and the shoulder and hip joints can rotate through a considerable arc, it is difficult to imagine an organic bearing that could rotate through 360 degrees.

Insect like appendages is unlikely. Insects possess legs that are basically hollow cylinders with muscles and tendons inside the skeletal tube. The problem with this arrangement is that if the creature grows in size the tube will constrain the inner muscle size — hence the Tarantula being the largest land insect left since prehistoric times. Hard levers and struts surrounded by muscles and tendons, as inland walking vertebrates, is a much more likely arrangement in the predator land-dwelling alien.

The question of the number of legs is one of the most contentious when discussed by those speculating on the morphology of the intelligent ET. The four legs that we have are the product of genetic inheritance from our earliest mammal ancestors, but this inheritance allowed us a great speed of movement and thus played a major factor in the development of intelligence.

One leg is out of the question — the creature could never get up if it ever fell over. Odd numbers are unlikely because of balance problems. More than four can only be found in insects. Galloping after prey with six legs is too complex for land predators (and herbivores, as we have established, are unlikely to become intelligent). Each leg has to swing through a wide arc for speed and with more than four this becomes very difficult.

Monkeys and apes can use their two legs for manipulation but have to run on both arms and legs together. Indeed the ape cannot use weapons to hunt whilst running on all fours. It is difficult to imagine the development of an intelligent hunting animal such as man running on two sensitive grasping appendages. Thus we have the evolutionary step of the conversion of one pair of legs to manipulating, pushing and pulling devices and the other pair to movement. In this way, the creature optimizes between high-speed movement and delicate manipulation.

8. SENSORY ORGANS

So far we have formulated the picture of an intelligent ET with a body much like our own. Its sensory organs, however, show characteristics that are somewhat different, though not greatly.

Sense organs would largely depend on the characteristics of the alien’s planetary environment and the illumination provided by the local sun.

More than two eyes are rare inland creatures — the spider possesses multiple eyes, but they are of doubtful sensitivity and would confuse a large hunting creature. Stereoscopic vision near to the brain and high on the body is the most suitable. Binaural hearing would seem the most logical. This is required for location bearing — and thus the ET requires just two ears. Again these would be on the head. Only one mouth is needed with the smell sensor close to it and taste sensors inside it. The smell sensor can be used for breathing, whilst the mouth is occupied with eating and drinking.

Additional sensory devices such as bat-like acoustic ranging systems or infrared sensors similar to those possessed by the rattlesnake are possible. But as Bieri points out, they imply a corresponding reduction of vision in the normal sun illuminated spectrum. As we have established above that carbon life probably only develops on planets with suns much like our own we can assume that the visual spectrum would be similar to that on Earth for the alien ET.

Although therefore, the sensors of the ET are similar to our own, the placement on the head and their form might be quite different. Oddly shaped heads are likely, different ear shapes and size most probable and eye size and color would be different.

9. THE LIKELY ET APPEARANCE

The argument presented above gives backing to the anthropomorphic view of the intelligent ET — that is that the creature would be basically humanoid. But this only a starting point. What would the intelligent ET look like in detail?

This question is, of course, even more, difficult to contemplate than speculating on the ET’s likely basic form. However, here are a number of possible variables to consider:

 1. SIZE AND BUILD — The height and build of the alien have often been suggested as being related to the gravity on the creature’s planet of origin. A planet slightly larger than Earth, with subsequently higher gravity would result in the alien being squatter, with heavy bones and a powerful physique — in other words, something like a gorilla. On the other hand, a lower gravity planet would result in taller, more spindly aliens. This argument is a little simplistic in its conclusion and does not explain the wide range in the sizes of Earth creatures — for example, why is there such a large variation in the size and build of the apes, all of which are fairly clever animals?

It seems probable that one can draw parameters about the ET’s size, the likely range being between the smallest of the human races (the pygmy) at about 4 1/2 feet tall and the upper limit being, around 7 1/2 feet tall. If the alien is very much heavier than man, he would have problems with running for long distances in pursuit of prey in his early development as a land predator and would require a very large supply of readily available food to maintain himself.

One interesting point about man is that we appear to be getting taller due to our evolution, our bodies are losing their broader muscles and our heads changing shape. It is more than likely that the humanoid intelligent alien also experiences this form of slow morphological evolution due to changes in dietary nutrition and lifestyle. There is, of course, no guarantee that the alien will meet a man as we appear now. An intelligent alien basing his conception of what man looks like from previously discovered spacecraft message devices (such as those carried by Pioneers 10 and 11), or picked up TV images in, say, 50,000 years time, maybe in for a surprise when he meets a hairless, chinless, towering egghead from Earth!

Equally interesting is the question of the differences between the male and the female of the intelligent aliens’ species. Would the two be quite different morphologically as in the case of homo sapiens, or would the two be virtually indistinguishable as with some creatures on Earth?

 2. SKIN COLOUR — The wide variation in skin color and tone with creatures on the Earth is enough to indicate the extreme range that could occur with the intelligent ET. Indeed, why would the ET have a smooth skin? It is possible that fur may cover the alien having been left behind after an evolution stemming from a bear-like creature, for example. (Indeed, it is interesting to wonder whether whiskers, or some sort of delicate sensory feelers may remain with an intelligent creature after it has begun to rely on its hands).

 3. FACIAL ARRANGEMENT — This, as already stated, is mainly constrained by the smell and taste sensors being close to the mouth and by the need for stereo vision and binaural hearing. Beyond this, the facial arrangement possibilities would be reasonably wide.

 4. The NUMBER OF FINGERS/TOES — Again, variations could be wide although beyond ten fingers or toes on each hand or leg would seem excessive and difficult for the brain to coordinate. Less than four fingers on the hand would make basic technology difficult to manipulate.

 5. INTERNAL CHARACTERISTICS — The internal digestive, cardiovascular and pulmonary systems inside the intelligent ET would most likely be quite different and it is not possible to list all the variations within the confines of this article.

10. THE LIKELY REACTION

Our immediate impressions of the intelligent ET will be critical to how society later reacts to the contact. The theme of this article is that, because of the evolutionary demands to become intelligent and the probable similarity between Earth and the alien planet, the intelligent ET will be basically humanoid in form. Therefore, our reaction will most likely not be too extreme.

Various questions, however, remain. For example, how far will the ET have evolved beyond the humanoid morphology?

It is unlikely that prosthetics will change the basic form of the ET. In general, artificial limbs (and bionics) are intended to resemble those currently possessed. The aliens’ view of good looks will be determined by the most perfect and healthy of its species. Consequently, any artificial aids will be designed to blend with the pure form of the alien — contact lenses replacing glasses is a good example of this.

It is difficult to imagine the advanced alien ever giving up its basic body appearance. Some writers have suggested that semi-immortality might be achieved by removing the brain from the failing body and installing it in a machine, thus creating the cyborg. If this is ever done it is likely that man would want the new machine body to resemble the original organic body shape. An even more radical idea is that once the alien has developed very high levels of knowledge and consciousness, the mind may even be liberated from the body. If this occurred we might never discover its original appearance.

A final question is to what degree will alien clothing and cosmetics mask the basic morphology? Fashions can enhance and emphasize body shapes in certain cases with our own current civilization — possibly the same will occur in the intelligent ET’s society. Hairstyling, however, is an example of how sometimes fashion can seriously alter the shape of the body. Also, any spacesuit or breathing apparatus might appear unusual.

Unfortunately, only through the discovery of artifacts or through contact itself will we ever learn what the actual morphology of the alien may be. Indeed, the chances are that the first close encounter with an alien civilization will be via the radio telescope. Video pictures will in this situation have to suffice for many years in the place of face to face contact.

It is the conclusion of this paper that these images of the intelligent ET will not shock us; they may surprise and intrigue us, but it is unlikely that mankind will find the alien fearful in physical appearance.

Hopefully, the ET will feel the same way about us.

REFERENCES

1. R.N. Bracewell, “Life in the galaxy,” reprinted in INTERSTELLAR COMMUNICATION, ed. A. Cameron (Benjamin, NY 1963).

2. Robert Bieri, “Humanoids on other planets?” AMERICAN SCIENTIST, LII December 1964

3. P.M. Molton, “Is anyone out there?” SPACEFLIGHT, 15,p.250, July 1973

4. S.W.P. Steen in the review of Freudenthals “Lincos” language, BRITISH JOURNAL OF THE PHILOSOPHY OF SCIENCE, 336, (1962)

5. D. Dooling, “Speculating on man’s neighbors,” SPACEFLIGHT, 17, p232, (Juen, 1975)

6. N.J. Berrill, “Worlds without end,” Chapters 9 and 10

7. Roland Puccetti, “Persons: a study of possible moral agents in the universe,” Macmillan, 1968