Primates, a diverse and ancient category of wild animals, consist of more than 233 living species and 13 families. All living primates have a few things in common, such as large brains, vision, hand adaptations for grasping, slow growth, fewer offspring, diverse social groups, and long life spans. They mostly live in tropical forests. Western lowland gorillas, mouse lemurs, rhesus monkeys, Macaca fascicularis, chimpanzees, and bonobo apes are a few groups of ancient primates.