Neurons for Numerosity: As Quantities Increase, So Does the Neuronal Response

Humans stand apart from other species in our ability to grasp higher math, but evolution laid the groundwork for numerical cognition long before ancient mathematicians drew symbols on clay tablets. The capacity for numerical cognition has been demonstrated in great apes, monkeys, numerous birds, dolphins, dogs, lions, rats, and raccoons, a list apparently restricted more by experimental inquiry than by inherent limitations in animals. In the wild, animals use this nonverbal ability to approximate number, called numerosity, to guide decisions on where to forage, when to flee from predators, and whether to fight intruders.