A team of researchers compiled brain data from more than 140 non-human animals  to study why primate brains are larger than other vertebrates In the study, the researchers not only considered the socialization of primates, such as race size, social systems and mating systems Their eating habits were also studied, and whether they ate leaves, fruit or omnivores
The results of the study did not show a relationship between fruit or leaf intake and brain volume in the same primate species
According to the researchers, dietary habits are the main reason for the large size of the primate's brain