Baboons have displayed a natural understanding of basic numbers similar to those of young children.
Eight captive olive baboons were tested in 54 separate trials where researchers placed one to eight peanuts in two cups. The monkeys would get all of the peanuts from the cup they chose to pick up, whether small or large. The baboons chose the larger quantity 75% of the time when given cups with a numerical difference of over three.
Known as the “more than or less than” cognitive approach, the baboons showed similar numerical abilities to those of children who are yet to learn to count and represents an important step in understanding the cognitive abilities of monkeys.
Read more at University of Rochester