Plesiadapis Facts

Name: Plesiadapis (Greek for almost Adapis); pronounced PLESS-ee-ah-DAP-iss Habitat: Woodlands of North America and Eurasia Historical Period: Late Paleocene (60-55 million years ago) Size and Weight: About two feet long and 5 pounds Diet: Fruits and seeds Distinguishing Characteristics: Lemur-like body; rodent-like head; gnawing teeth About Plesiadapis One of the earliest prehistoric primates yet discovered, Plesiadapis lived during the Paleocene epoch, a mere five million years or so after the dinosaurs went extinct—which does much to explain its rather small size (Paleocene mammals had yet to attain the large sizes typical of the mammalian megafauna of the later Cenozoic Era). The lemur-like Plesiadapis looked nothing like a modern human, or even the later monkeys from which humans evolved; rather, this small mammal was notable for the shape and arrangement of its teeth, which were already semi-suited to an omnivorous diet. Over tens of millions of years, evolution would send the descendants of Plesiadapis down from the trees and onto the open plains, where they would opportunistically eat anything that crawled, hopped, or slithered their way, at the same time evolving ever-larger brains. It took a surprisingly long time for paleontologists to make sense of Plesiadapis. This mammal was discovered in France in 1877, only 15 years after Charles Darwin published his treatise on evolution, On the Origin of Species, and at a time when the idea of humans evolving from monkeys and apes was extremely controversial. Its name, Greek for almost Adapis, references another fossil primate discovered about 50 years earlier. We can now infer from the fossil evidence that the ancestors of Plesiadapis lived in North America, possibly coexisting with dinosaurs, and then gradually crossed over to western Europe by way of Greenland.