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How high could apes rise?

Experts say the premise behind "Rise of the Planet of the Apes," the latest movie about intelligent chimps gone wild, is almost laughable. But they're not laughing about the wider issues raised by the cross-species romp — ranging from the genetic humanization of other animals, to the way we treat our fellow apes, to the long-running debate over the definition of "humanness."

Let's start by acknowledging that there's no way just administering a drug or fiddling with a few genes can confer human-type intelligence or language ability on chimpanzees or other non-human primates. "The scientific notion is preposterous," Jon Cohen, author of the book "Almost Chimpanzee," told me today.

Cohen said the oft-cited claim that there's a 1 percent difference between the human and chimp genetic code has led people to believe mistakenly that the two species are separated only by a few molecular tweaks here and there. When the differences in non-coding DNA are taken into account, that difference rises to 4 or 5 percent. Chimps and humans don't even have the same number of chromosomes (48 for chimps vs. 46 for humans).

"We have to get away from this vastly oversold notion that we're the same," Cohen said. "Let's grow up, and let's stop that."

The differences range from physiological factors (chimps don't suffer from the kinds of heart disease and cancer that afflict humans), to behaviors (humans can swim, chimps generally can't), to cognitive abilities. For years, primatologists have debated whether chimps can use language, or teach concepts to each other, or do math, or identify with the plight of someone else — but there's no debate that humans put chimps to shame in those departments.

Cohen thinks there are several factors behind our desire to think that chimps are like us:

  • Save the chimps: Conservationists may emphasize the similarities as a strategy to build up support for preserving wild chimpanzees in Africa, where they are an endangered species. "It works, because the public cares about chimps more than any other species," Cohen said. "But come on — we care about whales and elephants, and they don't look like us."
  • Support for evolution: A long time ago, some Darwinists pointed to the similarities as evidence of evolution at work. But that argument may be counterproductive now, since it's clear that humans and chimps had common ancestors that didn't look or act like either species. Current evolutionary theory rests on a wide array of evidence, and not just on the human-chimp connection. "We don't need that argument any longer," Cohen said.
  • We are not alone: "We're fascinated by the notion that we can communicate with species on other planets, that the universe isn't as lonely as it appears to be," Cohen observed. "If we could somehow have a chimp that was more like us, it would satisfy this deep science-fiction desire for communication with others, and make us feel less lonely. But it's a fantasy."

So unless you have 5 million years to spare, don't expect to take over the world by breeding an army of intelligent chimps. An army of intelligent robots is a more likely option. However, "Rise of the Planet of the Apes" does provide an opportunity for some serious reflection of the wholly human variety. Among the issues to reflect upon are these:

  • Humanized species: It's becoming more common to transplant our genes into other species — for instance, the mice who were given a "humanized" version of the gene linked to language and speech. Humanized mice are even being created in college science projects. The trend has rung alarm bells at the British Academy of Medical Sciences, which is calling for a ban on experiments that might give human characteristics to other primates. (Note the "Planet of the Apes" angle in this video.) Last year, U.S. bioethicists made a similar call for regulation, saying that it would be "ethically unacceptable" to conduct humanization research with apes. (Here's a scary sentence: "Imagine the life of the transgenic chimpanzee that, while no more self-aware than other chimps, is hairless, walks erect, lacks long canine teeth, or vocalizes like a human.")
  • 'Species-ism' at work: Even if chimpanzees are not as humanlike as some people may think, should they and other great apes be given special treatment? European regulators think so: They have ruled out most biomedical research on apes, while allowing experimentation on monkeys, our more distant relatives on the primate family tree. A similar debate over invasive chimpanzee research is simmering in the United States. Cohen says "species-ism" is a natural human tendency. We value mice over mosquitoes, monkeys over mice, and men over monkeys. "We do feel closer to some species than others, and we feel closest to the great apes because we're in the same family," he said. "But that doesn't mean tha we're them and they're us."
  • Defining humanness: Some may question whether chimps should qualify as "persons" under the law, but no one would confuse a chimp with a human. In fact, Cohen argues that one of the main reasons to study chimpanzees is to track down the roots of the differences between our species and our closest relatives in the animal kingdom. "It clarifies what a human is, and what it means," he said.

One of the closing lines of Cohen's book resonates particularly strongly as "Rise of the Planet of the Apes" goes into its big opening weekend: "Humans will determine the fate of chimpanzees. Chimpanzees of course will have no say in the fate of humans. And that may be the single most conspicuous difference between the two species."

Do you agree? Feel free to weigh in with your comment below. And, oh, by the way: Let me know how you liked the movie.

Extra credit: If you're looking for a blockbuster movie that's on firmer (but equally scary) scientific ground, Cohen suggests keeping an eye out for "Contagion," a meticulously researched action-thriller that's due to debut next month. Looks like it has a dynamite cast — Matt Damon, Gwyneth Paltrow, Jude Law, Kate Winslet, to name a few — but the trailer is making me feel a little skittish about putting my fingers on the computer keyboard.

More about chimpanzees and humans:

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