Northeastern Pacific Pleistocene Sea Otters

Abstract

Previously known by only one fossil bone from Oregon, the record of the sea otter is supplemented by description of 11 bones newly found in Late Pleistocene deposits at San Pedro and on Santa Rosa Island and one tooth from an Early Pleistocene deposit at San Pedro, southern California, all considered representative of the living species Enhydra lutris. Faunal associations suggest that the animals lived with cool-water faunas in areas of shallow to moderate depth near islands. The long-accepted hypothesis that E. lutris evolved from "Lutra reevei" during the Pliocene in the North Atlantic and migrated to the North Pacific is rejected on chronologic and zoogeographic grounds. The sea otter may be a North Pacific endemic autochthon.