Plesiadapis is one of the oldest known primate-like mammal genera which existed about 58–55 million years ago in North America and Europe.

Thanks to the abundance of the genus and to its rapid evolution, species of Plesiadapis play an important role in the zonation of Late Paleocene continental sediments and in the correlation of faunas on both sides of the Atlantic.

[2] Although the preservation of the hard parts is poor, these skeletons still show remains of skin and hair as a carbonaceous film—something unique among Paleocene mammals.

Plesiadapis' dentition shows a functional shift toward grinding and crushing in the cheek teeth as an adaptation towards increasing omnivory and herbivory.

Orbits are still directed to the side, unlike the forward-facing eyeballs of modern primates that enable three-dimensional vision.

[7] Plesiadapis had mobile limbs that terminated in strongly curved claws, and it sported a long bushy tail which is preserved in the Menat skeletons.

Climbing habits could be expected in a relative of the primates, but tree-dwelling animals are rarely found in such high numbers.

[2] However, more recent investigations have confirmed that the skeleton of Plesiadapis is that of an adept climber, which can be best compared to tree squirrels or to tree-dwelling marsupials such as possums.