The first primate like creatures evolved by the end of the Mesozoic era around 65 million years ago from the group of mammals known as insectivore, these protoprimates were similar in form to squirrels or tree shrews. Of similar size and form they were probably adapted for warm, moist climates and were probably arboreal in nature.
Towards the end of the Palaeocene epoch, about 60 million years ago, evolved the early prosimians from the genus altiatlasius. Fossils have only been discovered in Morocco but it is likely they existed elsewhere. These creatures were similar to the protoprimates but had grasping hands and feet for climbing and manipulating objects.
Around 55 million years ago, at the beginning of the Eocene epoch, we see the first recognizable primates in the form of early primates resembling modern prosimians, like lemurs. Their are 60known genera of these creatures divided into two families, adapidae (similar to lemurs and lorises) and omonyidae (Gallegos and tarsiers). That's nearly four times as many genera of prosimians as today indicating a degree of diversity that may be because of lack of competition with other species. These creatures could be found in North America, Europe, Asia and Africa and by the end of the epoch would reach Madagascar. These prosimian species had larger brains and eyes and were starting to hold their bodies upright while hopping or sitting. By the end of the Eocene epoch many prosimian species were extinct; this was probably due to cooling temperatures and the appearance of monkeys around 35 million years ago.
Monkeys may have evolved in the late Eocene period or the early Oligocene, 34 to 23 million years ago, and were the first species of the suborder Anthropoidea. Many species of monkey evolved, ranging in size from that of fat squirrels to a large cat, and they probably fed on fruit and seeds and lived trees in the forests. Monkeys had fewer teeth, less pronounced snouts, larger brains and more forward looking eyes than their prosimian ancestors. Many believe that competition with monkeys led to the extinction of most species of prosimians and this is reinforced by the fact that in the modern world prosimians mostly survive in areas never reached by monkeys, such as Madagascar. Towards the end of the Eocene primates mostly disappeared from northern areas, surviving only in southern Asia and Africa; this is probably due to a cooling trend.
The Miocene period, 23 to 5 million years ago, presents lots of primate fossils but they are mostly ape fossils, monkeys and prosimians are relatively rare. Apes evolved from monkeys during this period and may have taken over many of the ecological environments in which monkeys now survive. Around 14 million years ago the Genus Dryopithecus is known to have existed in southern Europe. The end years of the Miocene period saw cooling temperatures that led to the southern migration of many primate species, those which stayed in the north became extinct.
Around 9 million years ago the genus dryopithecines, which may be related to dryopithecus, split into two distinct evolutionary lines. One would evolve into the modern day gorillas and the other would become chimpanzees and Homo sapiens.
Approximately six million years ago the early hominids, later to become Homo sapiens, diverged from the chimpanzees.