Largest of the wild dogs; total length to 205 cm, tail to 50 cm, nose pad averaging 31 mm or more in diameter; upper canine more than 12 mm in anteroposterior diameter at base and not extending below level of anterior mental foramen when lower jaw is in place; peleage varies from nearly black to white, some shade of gray in most areas; condylobasal length of skull 203-269 mm (Hall 1981).

Steller sea lions are the largest otariid. Males grow larger than females. The average standard length is 282 cm in adult males and 228 cm in adult females (maximum of about 325 cm and 290 cm, respectively); weight of males averages 566 kg and females 263 kg (maximum of about 1,120 kg and 350 kg) (Fiscus 1961, Calkins and Pitcher 1982, Loughlin and Nelson 1986, Winship et al. 2001). Newborn pups are about 1 meter long and weigh 16-23 kg (Daniel 2003).

A somewhat bearlike mustelid with massive limbs and long, dense, dark brown pelage, paler on the head, with two broad yellowish stripes extending from the shoulders and joining on the rump; bushy tail; relatively large feet; 650-1125 mm total length, 170-260 mm tail, 180-192 mm hind foot; mass 7-32 kg; females average about 10% less than males in linear measurements and 30% less in mass (Hall 1981, Ingles 1965, Nowak 1991).

Pelage thick, mainly reddish, dark brown, or black, with the head whitish in older individuals, especially males; tail thick (to about 35 cm), about 1/4 of body length; hind feet flattened and webbed, outer toe longest, with vestigial leathery foot pads; front feet relatively small and round; ear pinnae small; to about 1.5 m in total length; adult males usually 25-40 kg, females usually 15-25 kg.

Color ranges from pale yellowish to dark brown; usually white tips on the hairs, especially on the back, resulting in a frosted or grizzled effect; facial profile concave; claws on front feet of adults about 4 inches long and curved; noticeable hump above shoulders; head and body of adults about 6-8 feet, height at shoulders 3-4.5 feet (Burt and Grossenheider 1964).

Resident adults are 15-30 cm in length whereas migratory adults commonly exceed 60 cm (see Rieman and McIntyre 1993).