Geographic Variation in Sea Otters, Enhydra lutris

Authors

Don E. Wilson, National Museum of Natural History, Smithsonian Institution, Washington, DCFollow
Michael A. Bogan, U.S. Fish and Wildlife Service, 4512 McMurray Avenue, Ft. Collins, CO
Robert L. Brownell Jr., U.S. Fish and Wildlife ServiceFollow
A. M. Burdin, Pacific Scientific Research Institute of Fisheries and Oceanography, Petropavlovsk-Kamchatsky, USSR
M. K. Maminov, Pacific Scientific Research Institute of Fisheries and Oceanography, Vladivostok, USSR

Date of this Version

2-1991

Comments

Published in Journal of Mammalogy, Vol. 72, No. 1 (Feb., 1991), pp. 22-36.

Abstract

Univariate and multivariate analyses of 20 skull characters of 304 adult sea otters from throughout the geographic range strongly suggest that three subspecies should be recognized. The nominate form, Enhydra lutris lutris, occurs from the Kuril Islands north to the Commander Islands in the western Pacific Ocean. Individuals of E. l. lutris are characterized by large size and wide skulls with short nasal bones. E. 1. nereis is found along the California coast and off San Nicolas Island, where the species recently has been reintroduced from coastal California. Specimens of E. 1. nereis have narrow skulls with a long rostrum and small teeth, and usually lack the characteristic notch in the postorbital region found in most specimens of the other two subspecies. A new subspecies described by Don E. Wilson in this report, occurs throughout the Aleutian Islands and southward in the eastern Pacific to Washington. Specimens of the new subspecies are intermediate in size in most, but not all, characters and have longer mandibles than either of the other two subspecies