30 Nov 2016

Bonobos in the News

Three months, three bonobo papers.

by Alina Loth, Research Illustration

Expressed and Understood Repertoires

Bonobos use 68 gestures, around 90% of which are shared with chimpanzees. In some species, signals are given only by males and received only by females – think bird of paradise mating displays. But bonobo males and females, young and old, all produce and receive pretty much the same gesture types. There are some gestures that only adults produce and only young understand, e.g. gestures that ask the young to climb on the adult’s back. But these gestures are few and throughout an individual’s lifetime, everyone should have the opportunity to use and receive all gesture types. Thinking about the massive overlap with chimpanzees, the next question is “do bonobo and chimpanzee gestures mean the same thing?”. I’ll keep you posted!

This article was covered by Research Illustration and Not Bad Science.

Nahoko and I were following an adult female, Hide, who was carrying what seemed to be a miscarried infant. She carried the infant carefully all day, and then suddenly took a bite out of it! Hide was a dominant female and she ate most of the infant, which is what you’d expect in a meat-eating or -sharing event. Deborah was at Kokolopori when field assistants saw another cannibalism event. This time, the meat was controlled by a dominant female (not the mother) but the mother also ate pieces. The event at Kokolopori sounds similar to a case at LuiKotale. So now we’ve seen maternal cannibalism (mothers eating their babies) at three different places, which makes it look like it might not be so unusual. We’re still not sure what drives maternal cannibalism – it could be nutritional. Maybe events like these can tell us something about how bonobo mothers consider the deaths of their infants, but we’ll (unfortunately) need more examples first.

This article was covered by BBC Earth

When my dad reads a menu these days he has to hold it at arm’s length. So would Nao, if she could read. Nao is a 40+ year old female bonobo. As bonobos get older they become more long-sighted. We measured this by looking at the grooming distance – how far is it between their eyes and their fingertips when they’re grooming another bonobo? They should keep their fingers at the point of focus from their eyes. Forty-years seems to be the point where bonobos, like humans, start to “hold the menu further away”. Bonobo eyes seem to age like human eyes. One of our side findings, which I think is quite sweet, is that while human ears continue to grow forever (sorry grandpa, I’m talking about you!), there was no difference in ear length for young and old bonobos (the caveat being that none of our bonobos is over 60). They all just have pretty big ears.

This article was covered by The New York Times, New Scientist and more...

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