The cheek teeth are much reduced. In color the males are dark gray, being a little lighter ventrally just after the molt, but through the year the coat fades to a rusty grayish brown. Fighting between bulls leads to intensive scarring of the neck region, and the scar tissue makes the skin of the chest extremely thick, tough, and cracked. The females are browner and generally darker than the males and have a light-colored yoke around the neck caused by the many small scars resulting from bites during mating. The hair is short, stiff, and harsh, and there is no underfur.
Additional information is provided separately for each species.
From M. leonina, M. angustirostris differs in having a smaller and less flexible body, less sexual dimorphism, a narrower skull with a longer rostrum and a greater degree of suture closure with age, and a larger proboscis in the adult male. This proboscis is very long, hanging down over the mouth about 30 cm when relaxed and showing a very deep transverse groove that almost divides it in two when inflated. Inflation causes it to curve down between the jaws and directs the nostrils toward the pharynx, thus snorts are directed down into the open mouth and pharynx, which act as a resonating chamber. The northern elephant seal currently breeds on numerous islands, from Cedros, off the west coast of central Baja California, north to the Farallons, near San Francisco. Preferred breeding sites are good sand or gravel beaches remote from human activity.