"Chimpanzees turned out to be big risk-takers, being invariably tempted to go for the grand prize even if this also meant frequent disappointment.
Bonobos, like humans, were strongly risk-adverse, and preferred to go for the fixed, dependable reward.
The chimps' love of risk is in keeping with previous findings. Compared with bonobos, chimpanzees are more patient, waiting longer to get their hands on a delayed treat.
And their risk-taking strategy is also confirmed by the fact that, unlike bonobos, they hunt, kill and eat colobus monkeys. If the hunt comes off, the group gets to feast on protein-rich colobus meat -- if not, they all go hungry.
The distinction is intriguing, because in many respects the two primate species are very similar, having diverged from a common ancestor less than a million years ago, which in evolutionary terms is recent.
They have similar body size and appearance and share much of the same behaviour and social hierarchy.
The difference, though, lies in their diet. Both apes feed heavily on fruit, but bonobos also tuck into herbaceous vegetation on the ground, which is a more reliable source of sustenance.
In addition, bonobos may also have access to larger fruit patches, facing less competition within a given patch than chimpanzees.
So what makes chimps gamble is a clever survival mechanism -- their food resources are less certain, which means they have learnt to cope with going for big or bust, say the authors, led by Sarah Heilbronner of Harvard University and Duke University, North Carolina."
Link to article in full here.
Guess that explains THIS: