Orangutans Confront Their Fear of Water For Sex

An adolescent female orangutan practices her ape stroke.
Image: Anne Russon / New Scientist

Orangutans (Pongo pygmaeus) are not the most dexterous of creatures (especially for primates) and this is particularly true when they're in water. Zoos across the country have removed the moats surrounding their exhibits precisely because of their tendency to sink. However, researchers Anne Russon, Purwo Kuncoro, Agnes Ferisa, and Dwi Putri Handayani have just published a paper in the Journal of Comparative Psychology showing how a group of orangutans on Kaja Island in Indonesia have developed an innovative use of their watery foe. Wouldn't it figure that sex had something to do with it?

As Russon told New Scientist:

My guess is that the male chose the location because there was less chance of him being interrupted by other, more dominant males.

However, the orangs appear to have overcome their fear and utilized water for a number of reasons, something that the researchers say reveals important clues about orangutan cognition and sociality. Innovation requires creativity to apply old behaviors to novel situations and the researchers argue that a similar process is at work in Pongo as in humans.

Interestingly, it was the mid-rank males who were most willing to innovate. This is probably because it is in the reproductive interests of alpha males to maintain the status quo and they therefore avoid "rocking the boat" or, in this case, coming anywhere near the boat. Mid-rank males, however, have much to gain and little to lose in their efforts to experiment with novel situations. Afterall, since alpha males typically dominate the mating opportunities in a given area, taking a chance with an attractive female could pay off in a big way. I'd be curious to know what the female's role was in all of this. Was she hesitant to follow her young beau into unfamiliar territory? Or did she dive right in, eager to avoid any interruptions from the guy with prominent cheek flanges and an intemperate disposition?

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Great post! It would make sense that those middle rank males innovate and find a way to mate. They are the ones who has much to gain and powerful enough to coerce (my guess) females. Similarly, like you said, it would be interesting if this is the female choice too ... I mean, we know that these males are no Prince Charming and almost always force copulate these poor females.

Prince Charming or not, it's a pic of a FEMALE orang desperately swimming. Go figure it out.

Ilya, he mentioned that.

By Katharine (not verified) on 20 Mar 2010 #permalink

Orangutan males have long been known to engage in coercive mating, however there is recent evidence that demonstrates female choice as well. See this study in the Proceedings of the Royal Society (Knott et al., 2010) and the National Geographic review of their research:

"Using the first hormonal data from wild orangutans, we show that around ovulation females preferentially encounter and mate with prime males whose impressive size and ornamentation are probable indicators of genetic quality," Knott and others write in their research paper . . . But when not ovulating, females mate willingly with unadorned males and those past their prime, the scientists discovered.