Between fear and appetite – Barbary macaques tested for risk-taking behavior

We are constantly faced with decisions: we want to achieve goals and receive rewards, but our decisions can also involve risks. Life history theory states that younger individuals should be more willing to take risks; although they have a lot to lose, they can also gain a lot by making risky decisions. Older individuals, on the other hand, have little to gain from making risky decisions and should therefore be less willing to take risks. Similarly, the theory predicts that in mammals, males should be more willing to take risks than females.

Researchers from the DPZ investigated how the risk-taking behavior of Barbary macaques changes with age. In an experiment, the animals were given the choice between a high-value reward (peanut) and a less attractive one (popcorn), each combined with a “high-risk” stimulus (rubber snake) or a “low-risk” stimulus (cube with a snake skin pattern).
 

The results contradicted theoretical expectations: neither age nor gender influenced the animals' decision to accept the reward offered. Only about one-third of the Barbary macaques reached for the popcorn when it was presented together with the rubber snake. Contrary to expectations, older animals took the popcorn more quickly than younger ones.

The researchers conclude from these results that risk-taking varies depending on the context. For older animals, a low-value reward such as popcorn seems to have a higher subjective value than for younger monkeys, who have more frequent access to high-value rewards.

Bosshard TC, Mundry R, Fischer J (2025): Ecological risk-taking across age in Barbary macaques. Animal Behaviour 229.

https://doi.org/10.1016/j.anbehav.2025.123337