You damn dirty ape

30 March 2012

Only one of these is a real monkey (hint: it's the ape)

In the summer of 1861, a debate concerning a seahorse-shaped brain structure, and its existence in the simian brain, gripped Victorian England. Well that might be an exaggeration, but the “Great Hippocampus Question,” an anatomical feud waged primarily by Sir Richard Owen on one side and Thomas Henry Huxley on the other, did stir up enough public attention to inspire satirical poems, editorial cartoons, and an extended passage in Charles Kingsley’s exceedingly strange book, The Water-Babies, A Fairy Tale for a Land Baby,

He held very strange theories about a good many things. He had even got up once at the British Association, and declared that apes had hippopotamus majors in their brains just as men have. Which was a shocking thing to say; for, if it were so, what would become of the faith, hope, and charity of immortal millions?

Though really, after all, it don’t much matter; because—as Lord Dundreary and others would put it—nobody but men have hippopotamuses in their brains; so, if a hippopotamus was discovered in an ape’s brain, why it would not be one, you know, but something else.

Though Owen adhered to his own idiosyncratic evolutionary theories, he scoffed at Darwin’s suggestion that humans shared a common evolutionary history with primates. To prove the anatomical singularity of humans, the great anatomist conducted a detailed study of human and primate brains and asserted that the absence in apes of certain structures in apes, the posterior cornu and hippocampus minor, set humans clearly apart from primates.

Owen’s rival (and Darwin’s champion) Thomas Henry Huxley seized upon the fact that these structures are in fact demonstrably present in non-human primates, and proceeded to waggle monkey brains at academic peers and public audiences alike to illustrate Owen’s error. Writing to his wife Henrietta about one of his public lectures, Huxley raved “My working men stick by me wonderfully, the house being fuller than ever last night. By next Friday evening they will all be convinced that they are monkeys.”

All of this was called to mind by a debate that simmered across the interscape last week which sadly failed to capture the public imagination, but at least, you know, triggered a few tweets. I’m calling this the “Great Ape Clade/Grade Tirades of 2012.” It all began with a post by Jerry Coyne on his “notablog” Why Evolution is True,

I believe it was William Jennings Bryan who denied during the Scopes trial that man was a mammal. That one statement laid him low, exposing his Bible-ridden ignorance for what it is. Of course we are mammals, and of course Richard is an ape. The Wikipedia definition is as good as any:

Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea.

Last time I looked, I was also a tailless catarrhine primate, so that makes me an ape as well.

This sparked a thought-provoking essay by anthropologist John Hawks “Humans aren’t monkeys. We aren’t apes, either.”

While I don’t entirely agree with Hawks–in fact I’m on record engaging in just the kind of misguided pedantry that Hawks deplores–he does make some good points. Hawks reminds us that there is no rule that vernacular names need to refer to monophyletic clades or formally recognized systematic groups. Evolutionary biologists that try to insist otherwise against popular usuage are swimming upstream at best, and at worst are probably reinforcing some negative stereotypes of scientists as out-of-touch type-A killjoys.

However Hawks’ advocacy for the paraphyletic “apes” and “monkeys” of everyday speech sparked a backlash. Brian Switek saw Hawks’ “humans aren’t apes” bet and raised him to “humans are fish.” Meanwhile Coyne doubled down on his original statement. Various tweets, retweets and countertweets ensued:

Setting aside for the moment the question of whose definition of “ape” is the correct one, it’s interesting to see the tension that arises when biological nomenclature and the popular vernacular converge and diverge. During this holy season of Lent we can all relate to the devout souls that happily fry up beaver tail and muskrat on Fridays, assured by the Vatican that beavers and muskrats are “fish” and not “meat.” And lest we think such distinctions are merely academic (or parochial), D. Graham Burnett’s Trying Leviathan describes how the question of whether or not whales are “fish” for tax purposes landed in a New York court in the 19th Century.

Of course, every fifth-grader learns that whales are not fish, but mammals. That is, until they get to my history of life class and they have to wrap their heads around the mind-boggling fact that whales are in fact “fish” in the most phylogenetically rigorous sense of the term, just as much as you or an elephant or a trout is.

Hawks finds such evolutionary rebranding of vernacular names distasteful,

We shouldn’t smuggle taxonomic principles into everyday language to make a political argument. That’s what “humans are apes” ultimately is — it’s an argument that we aren’t as great as we think we are.”

But elsewhere in his post Hawks belies that he in fact has his own taxonomically rigid view of what an “ape” and “monkey” properly are, it’s just that his taxonomy is not beholden to cladistic fashions.

My children can tell what an ape is. I work very hard to tell them why apes are different than monkeys. When they see a chimpanzee in a zoo, and other parents are telling their kids, “Look at the monkey!”, my children say, “That’s not a monkey, it’s an ape!”

If we must accept that humans are apes, then we must equally accept that chimpanzees are monkeys, and those awful parents at the zoo are right. I don’t.”

However, Hawks’ favored “correct” definitions for “ape” and “monkey” are actually rather modern constructions. Long before hominoids were known to the English-speaking world “Ape”  was a catchall word used for all primates, until “monkey” came into use around the 16th Century. The two were used rather interchangeably until “ape” began to be restricted to tail-less primates during the 18th Century. Even still, “ape” continued to encompass some tail-deficient primates such as the “Barbary ape,” a macaque that is “properly” now regarded as a monkey and not an ape. If the zoos themselves aren’t consistent I don’t know how we can expect the awful parents to get it right.

The fluid historical meanings of “monkey” and “ape” might be taken as evidence that vernacular taxonomies are inherently arbitrary. But in fact the etymological history reveals that as biological knowledge develops and increases, the vernacular language often changes to reflect. It was naturalists and biologists that emphasized the distinction between monkeys and apes and their taxonomy filtered into the public vocabulary, and eventually to Hawks and his children.

I don’t really think that nudging the English words “ape” and “monkey” into monophyletic compliance, with humans as apes and apes (including humans) as monkeys, is really a political tactic to demote humans. Rather I see it as a conversational tactic to promote evolutionary thinking. That seems to have been Huxley’s intent to convince the curious public that packed his lecture halls.
Alex Wild makes a great point in his post on the perennial “bug” vs. “bug” distinction, a taxonomic stumbling block that comes up within the first twenty minutes of any conversation with an entomologist (who understands “bug” to refer to a member of a specific order of insect possessing sucking mouthparts and hemelytrous wings rather than just, you know, any animal you might want to squash),

Bug” is a common name. What’s more, it is a common name for both the lay public and for insect specialists. That it refers to different organisms in the two cultural contexts does not change the fact that it is vernacular in both spheres.

Common names are particular to individual cultures and local contexts. That is their point. The beauty of common names is their fluidity. They are dynamic, ever-changing, adaptable. Vocabularies arise to suit people’s needs. Entomologists find a narrow meaning for Bug useful. Non-entomologists don’t. And that is fine.

The “traditional” senses of “ape” or “monkey” are not necessarily wrong, but neither should we try to restrict alternative uses. If Hawks still finds the old paraphyletic senses useful, far be it from me to try to exclude them.

Me, I’m on team Huxley.

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