Female chimps play with "dolls"

An article was published in the issue of Current Biology that came out today, which is about research into the behavior of chimps. Science News posted a story about it.

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Deep in a Ugandan forest, Betsy Wetsy has gone wild.

A new study finds that young females in one group of African chimpanzees use sticks as dolls more than their male peers do, often treating pieces of wood like a mother chimp caring for an infant. In human cultures around the world, girls play with dolls and pretend that the toys are babies far more than boys do.

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Science News

I'm always skeptical about anything regarding animal behavior that doesn't give hard numbers. The first part of that story says that these female chimps use sticks as "dolls" in greater numbers than males do, but not what those numbers are.

So I read further to find the numbers.

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Stick play occurred most commonly between ages 3 and 9. Females spent substantially more time carrying sticks than males did. Among chimps age 10 or less, 10 of 15 females and five of 16 males engaged in stick play at least once over the 14-year study.

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So over the course of fourteen years 15 animals played with sticks "at least once." I'm not saying it isn't interesting, but it certainly doesn't match up with the impression that female chimps are playing dollies all over the place.

The Current Biology article itself was kind of disappointing when I found it. It refers to several studies on primate sex differences that are problematic, as well as making some fairly stupid contradictions within its own body:

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Given that regular stick-carrying has not been reported outside Kanyawara, a social learning component appears important. ... The sex difference in stick-carrying in juvenile Kanyawara chimpanzees arises without any teaching by adults and is consistent with practice for adult roles. Our findings suggest that a similar sex difference could have occurred in the human and pre-human lineage at least since our common ancestry with chimpanzees, well before direct socialization became an important influence.

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:smack Or maybe, because this is only observed in one group of chimps, it's a socially learned behavior that they're learning from other juveniles and they are mimicking other animals that are the same sex as them? Those are things that have actually been observed in chimps before, after all. It seems like some ridiculous anthropomorphizing to make the leap from "I saw ten juvenile females and five juvenile males holding sticks over a fourteen year period" to "they are playing with DOLLS like LITTLE GIRLS and this can TOTALLY be applied to HUMANS."

But! Where are the reports of little girl chimps wearing pink and little boy chimps wearing blue?

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Originally posted by Marsilia

But! Where are the reports of little girl chimps wearing pink and little boy chimps wearing blue?

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You know, I think somebody actually did a study once to see if the females of some species of primate preferred pink over blue. I don't quite understand why when it comes to sex differences in primates scientists so often go dumb. I can only assume it's because they want to apply it to humans. Some of it can be (we're primates too, after all), but the science has to be more solid than "I think chimps are imagining sticks are babies."

If chimps are capable of that sort of symbolic play that is far, far, far more interesting than the content of the play itself. But first you have to prove that's what they're really doing.

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Originally posted by Zuul

If chimps are capable of that sort of symbolic play that is far, far, far more interesting than the content of the play itself. But first you have to prove that's what they're really doing.

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Exactly. If they can prove that these chimps are using sticks as dolls, it could imply an amazing capacity for imaginative play. It's not like the scientists are passing around toy chimps to the chimplets and they're treating them like babies.

I am now imagining little girl chimps in gingham dresses holding a tea party for a bunch of sticks.

It's either that or they use them to beat the little boy chimps off if they do something inappropriate.

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Originally posted by CatInASuit

It's either that or they use them to beat the little boy chimps off if they do something inappropriate.

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Now, I'm picturing momma chimps using their babies as clubs to attack aggressive males.

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Originally posted by Marsilia

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Originally posted by CatInASuit

It's either that or they use them to beat the little boy chimps off if they do something inappropriate.

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Now, I'm picturing momma chimps using their babies as clubs to attack aggressive males.

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Perhaps their mothers stick babies into termite mounds and lick the bugs off...

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Originally posted by Marsilia

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Originally posted by Zuul

If chimps are capable of that sort of symbolic play that is far, far, far more interesting than the content of the play itself. But first you have to prove that's what they're really doing.

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Exactly. If they can prove that these chimps are using sticks as dolls, it could imply an amazing capacity for imaginative play. It's not like the scientists are passing around toy chimps to the chimplets and they're treating them like babies.

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I would love to hear specific examples of how the chimps were treating the sticks like babies...did they try to nurse them?

Nope.

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Stick-carrying consisted of holding or cradling detached sticks (median length, 36 cm; median weight, 112 g; n = 6 recovered sticks). The juveniles carried pieces of bark, small logs or woody vine, with their hand or mouth, underarm or, most commonly, tucked between the abdomen and thigh (Supplemental information). Individuals carried sticks for periods of one minute to more than four hours during which they rested, walked, climbed, slept and fed as usual.

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That's it?

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Originally posted by Zuul

Nope.

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Stick-carrying consisted of holding or cradling detached sticks (median length, 36 cm; median weight, 112 g; n = 6 recovered sticks). The juveniles carried pieces of bark, small logs or woody vine, with their hand or mouth, underarm or, most commonly, tucked between the abdomen and thigh (Supplemental information). Individuals carried sticks for periods of one minute to more than four hours during which they rested, walked, climbed, slept and fed as usual.

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So, at best, they were treating the sticks like a security blanket?

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Originally posted by Sarahfeena

That's it?

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In the cited group of chimps, yep. And unfortunately, most people don't go out of their way to find the original research to see when something is being misrepresented. There have been cases where chimps have been observed doing more than that, but it wasn't split along sex lines and they were usually chimps raised by humans so it's more likely learned behavior than imaginative play.

I was all set to blame the media for this, but it sounds like the researchers themselves were coming into it with an agenda.

Chimp behavior does not correlate to human behavior. Proving that chimps have sex specific behaviors does not prove that gender is hardwired. And yet that's exactly what they keep looking for.

Plus, their inclusion of the study on girls with congenital adrenal hyperplasia preferring male toys is muddying the waters. Those girls also tend to identify as male. If a child who identifies as male behaves in a stereotypically masculine manner, is that behavior occuring because of a masculinized brain or because the child identifies with the male role? Since there is probably no "play with trucks/play with dolls" switch in the brain, the simplest explanation is that people will gravitate toward the behaviors exhibited by people they identify with.

Some people in the sciences still don't grasp what culture is, though.