A new study says monkeys can carry out basic maths in their heads, which suggests that basic mathematics is "hard-wired into evolution".
Professor Andreas Nieder, who led the study at the University of Tubingen, Germany: "It is a primitive version of maths which we think has a survival advantage.
"If you are foraging then it is an advantage to choose a tree with more berries on it.
"Similarly it is important that a monkey knows the number of individuals in his or her social group and compares it with rival groups. To know whether to attack or retreat."
The study has been published in the Proceedings of the National Academy of Sciences.
To reach the conclusion, researchers made monkeys recognise the number of dots on a screen flashed before them and compare them with subsequent sets of dots shown to them later, reports The Telegraph.
The monkeys made the correct decision up to 90 per cent of the time, the study found.