The swimming mechanism of the Otariidae is centered near the forepart of the body, and locomotion in water is accomplished mainly by use of the forelimbs. Phocids swim primarily by strokes of the hind flippers. Sea lions have a blunt snout and a coat of short, coarse guard hairs covering only a small amount of underfur. Fur seals have a more pointed snout and very thick underfur, which may be of considerable commercial value. The pelage of newborn otariids is silky, never woolly.
Females usually have two pairs of mammae.
In males the testes are scrotal and the baculum is well-developed. The otariid skull is somewhat elongate and rounded, though rather bearlike in overall appearance. For example, the otariid skull has supraorbital processes and only slightly inflated tympanic bullae, the Odobenidae lack supraorbital processes and have moderately inflated bullae, and the Phocidae lack supraorbital processes and have well-inflated bullae. The number of upper molars varies within and among genera. Eared seals inhabit arctic, temperate, and subtropical waters.