Animals of science: the monkey (almost) always makes the best decision

“Beasts of science” is like a collection of stories. Beautiful stories that tell the living in all its freshness. But also in all its complexity. A parenthesis to marvel at the treasures of the world. For once, let’s take a look for the second time in a row at our favorite cousin: the monkey.

The Vervet. You know ? It is a species of monkey that lives in the east and the southern africa. A relatively small monkey since it weighs around five kilos for a maximum size of 60 centimeters to which we must still add a tail of almost 70 centimeters.

This monkey lives in a group. Large groups that can gather up to 50 individuals. Males, females and young. And what is special about it is that it knows how to adapt quite well to the presence of humans. A little too much even since he does not hesitate to venture into cities. Or on the plantations. What is worth besides to him sometimes to be driven out. However, it is not (yet) in danger.

Another peculiarity that researchers have discovered in him is a sense of planning that goes hand in hand with a rather developed sense of direction. So if you are one of those people who have a habit of getting lost on the road to vacation, you could well take Vervet as an example. In the meantime, let the ethologists tell us more precisely what they observed in wild monkeys from central Uganda.

Decisions based on multiple information

They prepared for them an experience rich in lessons. On five platforms arranged on the vertices of a regular pentagon, the researchers deposited corn kernels and bananas trapped in a holey box. On four platforms rested but and on one, bananas. You should know that Vervet literally loves bananas. The problem for him here is that the bananas are the ones that the researchers had decided to make the most difficult to access. Hidden in a box that you have to shake or roll to get them out.

First observation: the Vervets have shown themselves to be quite adept at figuring out how to retrieve the bananas from the bottom of their box. The less gifted took just over a minute to figure out the trick. The others did it without even having theair to think about it.

But the most surprising observation that ethologists have made is that these monkeys did not make choices dictated solely by gluttony. Before starting, they took their situation into account. Understand their rank in the hierarchy of the group, their ability to manipulate the banana box or the presence in the vicinity of a direct competitor. When the risk was deemed low, the Vervet studied took a route that minimized travel costs. When the risk was deemed high or the monkey had shown poor handling of the box, the Vervet rushed… to the bananas. To devour them without waiting and risk that they escape him. When the risk was judged to be moderate, the Vervet of lower rank took the time to stop just on a maize platform before joining that of the bananas.

As a result, in most cases, the Vervet studied manages to appropriate its favorite food. Or in any case, a maximum total amount of food. Enough to show how complex the decision-making process in this monkey in particular can be, based on the synthesis of numerous information, ecological or social. And how fast it is! What finally prove that the Vervet… is not so stupid!