h, 1968, when all men were Charlton Heston; all women were mute, scantily clad Linda Harrison; and "damned dirty ape" was considered a compliment. Oh, wait, that was 3968. In 1968 it was VW Bugs, rockets to the moon and interspecies snobbery.
When I was in school, the zoology of large primates was simplicity itself: you had your Pongids, the "great ape" family which included three species: the chimps (Pan troglodytes), gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus). And then you had your Hominids, the family of humans, of which Homo sapiens was the only surviving member. This seemed to make perfect sense, because the apes were all hairy, knuckle-walking forest dwellers, whereas the humans were hairless dwellers of the plains and coasts. The two families were thought to have a common ancestor, somewhere back in the mists of time, but to have split into two quite separate branches of the family tree.
Unfortunately, like many judgments based on appearances alone, this simply wasn't true. As the fossil record filled in over the '70s, '80s and '90s, it became clear that orangutans, not humans, were the odd species out. The common ancestor who gave birth to the humans, chimpanzees and gorillas may have lived as recently as 5 million years ago--the blink of an eye as far as evolution is concerned. Our second cousins turned out to be first cousins, while the ancestor we share with the orangutans probably lived around 8 million years earlier.
Being Human Isn't So Unique
When we started seriously poking around in the genomes of these various primates, the results were equally startling. Orangutans, while still the most distant of our cousins, nonetheless proved to be a lot closer than expected. And while gorillas, based on the evidence of body shape, had been hailed as our closest relatives ever since their discovery in 1847, the rather less dignified chimpanzees turned out to be closer still; they share between 97% and 99% of our DNA. The primary difference is a single "translocation," in which two of the 24 ape chromosomes fused together, leaving behind the human's odd 23. There are also nine "inversions," where segments of a chromosome have somehow been stuck in backwards. Fundamentally, humans and chimpanzees are separated by only 10 distinct mutations, so that "humanism" can in some ways be considered a heritable, non-lethal genetic disorder of chimps.
This is a sobering thought in a culture where apes of all kinds are routinely kidnapped from the wild and placed in zoos or circuses or, worst of all, in laboratories where they're deliberately infected with the most horrific of diseases. That's a hell of a way to treat a cousin. Still, human beings have astonishing powers which these other primates clearly lack. Right? Unable to speak, or write, or draw pictures, or use tools, or act out imaginary scenes to make a point, the apes are clearly a lot less intelligent than we are, belonging unambiguously to the animal kingdom whose subjugation has long been our trademark. In other words, it's no more cruel or immoral to exploit apekind than it is to farm pigs, or to hunt foxes for sport. Right?
Wrong. Unfortunately, this comforting theory is no more true than the last one. Chimps, gorillas and orangutans do for the most part lack a neocortex, the wrinkly outer layer of the human brain which contains our centers of language and planning and organization. But it's a huge step from there to the presumption that apes cannot speak or plan or organize. In fact, these specialized organs simply allow humans to perform such feats without training. (For more about the instinctive nature of human language, see "Speaking in Tongues, Baby!") Other complex tasks, such as reading, arithmetic and how to build a fire, are not instinctive and must be crammed into our more generalized brain tissues, in a process known as "learning." And while our furry cousins have no instinct for these human traits, they do in fact have the ability to learn them.
Apes, of course, have "languages" of their own: animal calls which convey information, such as the presence of danger or food. There isn't much room for abstract concepts here, but apes have proven deft at understanding spoken English, even when the concepts being discussed are less than concrete. Unfortunately for them, the human vocal tract is extremely complex, and makes a variety of noises which the apes simply aren't capable of. In the mid-20th century, primatologists Keith and Cathy Hayes succeeded in training a female chimp to speak four words, which remains a record to this day.
If We Could Talk to the Animals
The first ape to be taught sign language was a young chimp named Washoe, in 1966, and since then dozens of chimpanzees, gorillas and even orangutans have picked up the art as well. There are numerous observations of trained chimps using sign language among themselves, and several documented cases of chimps (including Washoe) successfully training other chimps to sign, with no human assistance. So while language is not a part of chimp anatomy, it can certainly be a part of chimp culture.
Apes have also had a lot of success with visual keyboards, which let them express nouns, verbs and even adjectives by pressing on pictographic symbols. The most recent and elaborate study, released in 1998 by researchers at Georgia State University, demonstrated that bonobo chimps--the most intelligent and humanlike of apes--can "speak" in complete sentences, with a vocabulary of dozens of words. The bonobos also like to watch TV, and are especially fond of dramas and comedies about primate-human interaction.
And then of course there is Koko, easily the world's most famous gorilla, who has been raised and educated by the human Francine Patterson since 1972. Koko knows over 400 words in American Sign Language, and uses them to construct jokes, rhymes and even the occasional metaphor. And using human IQ tests, which have in no way been adjusted for the cultural gap between gorillas and humans, Koko is consistently able to achieve a score of 80. By contrast, the legal cutoff point for mental retardation among humans is usually between 70 and 75. So while Koko's communication skills may be comparable to those of a profoundly retarded human, her inner life would appear to be much richer.
These points are still controversial--there are many researchers who dismiss the claims of animal trainers as a mixture of bias, wishful thinking and politically motivated fraud. Nonetheless, there is an increasingly vocal minority in the Western world who are agitating for ape civil rights--in fact, several such bills have come up for vote in Western countries. The passage of such a law would have profound consequences, in that apes could not be held captive without their consent. Unfortunately, numerous experiments in the 20th century have demonstrated that while juvenile apes get along well in human society, adult ones tend to be extremely violent and destructive. Simply allowing them to roam the streets of our towns and cities is clearly not a solution.
But then, neither is leaving them alone in their forests, where they are subject--legally or no--to every imaginable form of human exploitation. Perhaps we should institute mandatory schooling for ape children, much as we do for humans, so that their forests will gradually evolve into semicivilized townships. This is not to say that our furry cousins will be, er, aping us--they're clearly smart enough to build houses and wear clothing, but just as clearly choose not to. But if they were able to communicate, and perhaps even select human representatives to speak and vote on their behalf, then maybe, just maybe, they'd be able to wrest back some control of their lives and homes in this human-dominated world.
In any case, the field of zoology is adapting to these revelations in a simple but far-reaching manner: today, humans are generally regarded as one of four species of great apes, while gorillas and chimps are frequently moved into the primate family Hominidae. Orangutans remain where they've always been, in the family Pongidae, but this branch is now placed much closer to our own on the evolutionary tree.
To me, this is a pleasant thought: after believing for millennia that we belonged to the one and only species of human, it's comforting to learn that we "damned dirty apes" have been living on the planet of the hominids all along.
Wil McCarthy is a rocket guidance engineer, robot designer, science fiction author and occasional aquanaut. He has contributed to three interplanetary spacecraft, five communication and weather satellites, a line of landmine-clearing robots, and some other "really cool stuff" he can't tell us about. His short fiction has graced the pages of Analog, Asimov's, Science Fiction Age and other major publications, and his novel-length works include Aggressor Six, the New York Times notable Bloom, and The Collapsium.
