Enaliarctos tedfordi

Enaliarctos tedfordi is an extinct species of mammal that represents the oldest known member of Pinnipedia, the group that includes modern seals, sea lions, and walruses. This species lived during the late Oligocene Epoch, approximately 29 million years ago, and its fossils have been found in Oregon.1

Enaliarctos was a fish predator in the marine communities off the western coast of North America. It possessed specialized hind limbs for flipper-like movement and a flexible vertebral column, enabling strong swimming abilities. Unlike modern seals, Enaliarctos could also use its hind limbs for land locomotion, similar to sea lions. The evolution of pinnipeds, including Enaliarctos, is linked to changes in ocean circulation patterns that increased marine productivity.1