Quit Monkeying Around

Scientists reckon apes can explain humans’ gambling habits. But Null reporter, Bryan Hatton, is dubious. He thinks their behaviour might teach us more about our sex lives.

Primatologists recently published the findings of a study on risk preferences in humans’ closest relatives: chimpanzees and bonobos. In essence, they found that whilst bonobos tend to be risk averse, chimps are prone to have a little flutter.

So how do you encourage an ape to gamble? Easy. The scientists, working at Leipzig Zoo in Germany, simply stocked their cupboards with grapes. Apes of each species were first taught to distinguish between two different bowls. One of the bowls always had four grape halves in it and the other had either one or seven. The animals were then presented with both bowls and allowed to choose between them.

The bonobos usually played it safe and chose the bowl that guaranteed four grape halves, while the chimps preferred to take a gamble and usually chose the bowl with one or seven in it.

Chimpanzees and bonobos are very similar in appearance, genetics and physiology. Their differences are mostly behavioural and are thought to arise from the environments they live in.

Both eat mostly fruit, but bonobos tuck into more veggies while chimps supplement their diet by hunting colobus monkeys. Hunting is an all or nothing activity. Either the chimps end up with plenty of meat or they waste their time and energy to get nothing but the sight of a frightened monkey fleeing from them.

Bonobos, on the other hand, have larger feeding grounds and experience less competition with other bonobo groups. This means they have a more reliable and stable food source than chimps.

This has been given as the explanation for the results of the Liepzig Zoo study. As chimps engage in the risky business of hunting they are less averse to. Their differences are said to have been engrained in them through evolution, as the animals studied were captive born and kept in similar conditions. Scientists say the results may have implications for humans, as we are thought to be more closely related to the risk-averse bonobos. That’s despite the popularity of gambling amongst humans, apparently.

The study looked at just five apes of each species. And surely it could easily be argued that the unreliable nature of a chimp’s food source causes it to be more risk averse? If you don’t know where your next meal is coming from, is it not better to take a guaranteed meal rather than take the risk of going hungry? Still, making up explanations for your results is a big part of the fun of science.

I have an alternative explanation for these results. Bonobos have sex a lot; boy on boy, girl on girl, most combinations of incest. They have sex to say hello, to resolve conflicts, to make up after conflicts (okay, we do that one too). They also frequently have sex on discovering a new food source, allowing them to get rid of their tension and excitement and more peacefully sit and eat together. In fact, we could learn a lot from our closest relatives, but that’s a different matter. The point is that perhaps bonobos are far too content, and probably tired, to engage in risky gambling activities, or to even care about whether they get four grape halves or seven.

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