The Success of the Primates

Many speculative evolutionary scenarios have primates going extinct. However, as we shall see, primates are actually very adaptable and successful creatures, and will very likely survive into the future.

The first primate, Purgatorius, appeared in the Late Cretaceous or Early Paleocene of North America. If one were to look at this animal, the idea that these animals led to monkeys, or even us, would not come to mind. This animals was about the size of a possum, and if one could not tell that this animal gave live birth, one might mistake it for an odd possum as well.

The actual age of Purgatorius is in debate. Some fossils of Purgatorius seem to suggest that it was present in the Late Cretaceous, while other scientists seem to suggest that Purgatorius is earliest Paleocene in age, and the Cretaceous fossils in question were washed out of their original burial position and reburied in Cretaceous strata. However, if the former idea is true, then the primates would have been around during the Cretaceous…and survived the infamous bolide impact that killed off the dinosaurs. Even if Purgatorius is not Cretaceous in age, genetic studies have shown that the earliest primates probably originated somewhere in the later Cretaceous, and even barring that the primates more archaic relatives, the tree shrews, probably evolved during the Cretaceous.

Tree shrews are also around today. Like mentioned above, they are not related to shrews as all, but would be better classified as primitive primates. But the treeshrews are actually classified in their own group, Scandentia, in the grand scheme of mammalian classification. Many species of Scandentia today are considered low-risk, and are rather likely to survive into the future.

Primates themselves have also proven to be adaptable and widespread. Primates are actually rather generalized mammals, retaining five digits on each limb, a full set of teeth (in comparison to other mammals, such as felids and bovids, who have lost many of their molars, canines, and incisors). They have survived for quite some time as well.

Primates have had two great radiations, one of the non-simiomorph primates (lemurs and tarsiers), which include the lemurs as well as extinct groups such as adapids and omomyids. However, due to the Eocene drying, primates began to become restricted in their range. Once found on North America, Asia, Africa, and Europe, primates became restricted to Africa. However, once there, primates adapted, and thrived. Then came the radiation of the “advanced primates” the simiomorph primates, which include all of the monkeys and apes of the world today. In addition to the various species of arboreal African monkeys, this radiation also resulted in the South American monkeys, the platyrhines; the baboons, and the lineage that led to our family, the great apes and hominids.

While several lineages of primates, such as the modern apes such as gibbons, chimpanzees, gorillas, and orangutans are critically endangered, and their chances for surviving into the future seem rather dim, many of the other primates appear to be doing okay. There are over 350 species of primates, making it the fourth largest order of mammals outside of bats, rodents, and the shrews. Many of these are very likely to survive, and are not endangered at all. While they may not deviate further from their arboreal lifestyle, primates are very likely to survive into the future.