Last month we looked at the possible nature of life on other planets. Our current understanding of the nature of evolution points to the probability that no other planet will have lifeforms like our own, although certain solutions to life's problems will probably be expressed again and again, no matter where they might originate. Any intelligent aliens are unlikely to look much like us, and the SF stable of Klingons, Minbari, Bajorans, Pring, Greys and the like have much more to do with our own prejudices than anything else.
Still, the lure of humanoid life is very strong for many, and the possibility of finding humanoid (or even human!) life amongst the stars cannot be discounted entirely. If this is what you're looking for, read on...
Eliminating the Suspects
So, if you want to populate your Universe with humanoid aliens but want to keep the science as tight as possible, how do you start? Probably the best thing to do is to eliminate the tired, hackneyed explanations that crop up all too often, so we can concentrate on the good ones. Let us begin.
We Came From Outer Spaaaaace
"Some believe that life here, began out there. Far across the Universe. With tribes of Humans, who may have been the ancestors of the Egyptans, the Toltecs, or the Mayans. Some believe that there may yet be brothers of Man who struggle to survive, somewhere far beyond the heavens..."
OK, the older gamers amongst us probably recognise the introduction of "Battlestar Galactica", and it certainly has an appeal. The idea that Humanity are the descendants of shipwrecked starfarers is a compelling one, and storywriters have used it to some effect, telling some wonderful stories as they went.
Sadly, it just doesn't stand up to scrutiny. We're too closely related to the other species of Earth to have come from an alien biosphere, and there is a very complete fossil record linking our species with the other Hominids, and through them to other primates such as apes, monkeys, flying foxes and lemurs. We're too "plugged in" to the fossil record to be anything but the children of Earth.
Still, this idea does have some hard SF possibilities, and we'll be looking at it from a different direction later.
Perhaps the most overused explanation is that of "convergent evolution". The basic idea is that there are only a limited number of viable solutions to the problems of survival, and these ideas will be hit upon again and again by different lifeforms. This will force the lifeforms involved to adopt certain shapes, regardless of their genetic heritage.
There is indeed quite a bit of evidence to back this up. If you look at the faces of a snail, a tiger and a spider, for instance, you will see that there are some striking similarities. They all have eyes set forward of and atop the head, with the mouth set forward and below. Molluscs, arthropods and chordates are very different forms of animal, so the ony explanation is that this setup is highly beneficial to an active animal. Indeed, long-extinct groups also seem to prefer this layout, so the evidence is quite strong. Many unrelated animal groups have developed bilateral symmetry, although the echinoderms (starfish, sea urchins etc.), who are very closely related to us chordates, have kept a radial symmetry. This would suggest that bilateralism has been hit upon in many unrelated events, rather than being inherited from a single common ancestor. Another example would be the streamlined shapes of squid, fishes and dolphins. Although these animals are only distantly related (or not at all), this sleek, elegant shape allows for speed and maneouverablility in the water. The eyes of cephalopods (octopodes, squid and cuttlefish) are very similar to our own eyes, meaning that the "camera eye" has been invented more than once.
Still, there are other characteristics that don't crop up again and again. The land vertebrates' tetrapod limb configuration, for instance, is unique to the land chordates. That the limb-structures are set before and behind the vital organs doesn't apply to the arthropods, who cluster their limbs in front of their abdomens. The molluscs go so far as to set the limb(s) straight off the head/body interface, while the echinoderms simply set the limbs along the animals' circumference. Breathing orifices, sexual organs and some sense organs are similarly varied. It would appear that nature does not always favour the same solutions, so the idea that billions of years of evolution on another planet would provide something that we would call humanoid is vanishingly small.
Now For the Good Stuff
Now we've eliminated the non-runners, we can look for a way to invent humanoid aliens that don't beggar believability.
They Came From Right Here
Turning the "We Came from Out There" indea on its head, a very simple and elegant new solution presents itself. We've established that anything that looks humanoid must come from Earth's biosphere, from our own ancestors. There are several candidate species that could give rise to new humanoids, so let's have a look at them.
Australopithecus Afarensis and Australopithesus Africanus
These earlies hominids, the first of our family, were about a metre tall, slender of build and already fully upright. A female skeleton, dudbed "Lucy", was discovered in Olduvai Gorge in Tanzania some fifty-odd years ago. Essentially, she was a Chimpanzee (same size brain) who walked upright and lacked the chimps' great strength, and had left the forests for the more open plains.
Australopithecus Robustus and Australopitecus Boisei
The genus Australopithecus took a new turn when these species showed up. About a 1.3-1.5 metres tall, Robustus was heavily built in body and jaw. It would've been rather stronger than a modern Human overall, more along the lines of a Weren for strength. Boisei was a little taller and of the same heavy build as Robustus, but the cheekbones and muscles were much more heavily developed. Boisei could quite literally have cracked brazil nuts in its teeth!
At the same time as the big, heavy Australopithecines were around, the first species of the genus Homo appeared. A little shorter (about 1.2-1.3 metres), Habilis was also much slighter, more like Afarensis. What sets Habilis apart is that it had already begun to make more sophisticated tools than the Australopithecines, a feature that would be the hallmark of Humanity. Its brain was also rather larger, and it was probably the first hominid who could truly speak.
By the time Erectus came on the scene, the Australopithecines had died out, leaving no descendants. Erectus was alone. Larger than Habilis (1.4-1.5 metres), Erectus had a larger brain and made more sophisticated tools. Erectus was also a great innovator. They learned the principles of simple marine navigation (they could ride logs or simple rafts a few miles, following ocean currents in Indonesia), and they were the first species to master fire. They were also the first Hominid species to leave the African Rift Valley and begin to explore the world. At this time, the Rift Valley was experiencing an upsurge in Vulcanism, and the hostile climate set off these first migrations. Erectus was a survivor.
And so, here we are. The direct descendants of Erectus, we have moved into every niche in the Earth and begun to explore space. We have domesticated animals and plants, created agriculture and industry, and now have the power to improve or spoil the nature of our world. An important offshoot of our species were the Neanderthals.
Homo Sapiens Neanderthalensis
A subspecies of Sapiens, the Neanderthals were built for cold. Strong and short (about 1.5 metres), Neanderthals lacked some of our agility. Their tools were more primitive than those of contemporary modern Humans, and their art was almost non-existent, but their brains were a little larger than our own, and they were equal to us in many ways. Indeed, some learned to copy the more sophisticated technologies of their neighbours. They illustrate how a single species can adapt itself to a new environment.
These species represent the family Hominidae, the Humans. Any of these could (and maybe will, if we get our fingers out) have given rise to starfarers, and any could provide a basis for a Humanoid alien.
Of course, none of these species has yet reached the stars, so how could they get out there for us to meet them? What we need is an outside force to help. Imagine an alien species visited the Earth two million years ago (the day before yesterday in evolutionary terms). They would have seen Afarensis and Africanus, as well as some other clever great apes, and perhaps realised the potential of Earth's rich biosphere. If worlds of complex life are rare, it is possible that starfarers may use the species of such worlds to seed more barren worlds with life, to increase biodiversity across the Universe. It is possible that they could also take presapient species along, and "uplift" them to sapiency, rather like David Brin's "Uplift" novels. If this has happened, then maybe every hominid species has living descendants somewhere, living in Earthlike biomes, perhaps with other terrestrial species taken with them. Add in the possibility of genetic tinkering to help these colonists adapt to their new homes, and you can readily create a whole menagerie of humanoid aliens for your world. Maybe some are smaller than Afarensis, while others are taller than the tallest modern Maasai. Perhaps they have developed muzzles for improved scent, or more sensitive eyes and ears. Maybe a low-gravity world with a thin atmosphere has given rise to barrel-chested lanky giants with booming voices, or a high-g world populated with squat musclemen could exist. And yet, all of these new aliens will be Human, our own long-lost kin.
This concet can also give rise to intriguing mysteries. Why did the aliens naver set up a permanent base on Earth? Were they preserving the "root-stock?" Are they stil around? Are the humanoids perhaps members of the alien civilisation, or have they been left to their own devices? Have any of them developed star travel, perhaps before ourselves? the possibilities are all but endless, and yet we've kept ouirselves quite rigidly within the bounds of what is scientifically plausible.
I hope these ideas will help you to create new species and storylines for your own games.
© Mark Peoples 2001.
"Battlestar Galactica" is copyright Glen Larson Productions and Universal Television inc.