The limbs are short and bear five digits each. The claws are compressed, curved, and nonretractile. The claws of badgers are large and heavy for burrowing. The digits of otters are usually webbed for swimming. Well-developed anal scent glands are present in most genera.
Males have a baculum.
The skull is usually sturdy and has a short facial region. Enhydra is the only genus with 2 lower incisors. The incisors of mustelids are not specialized, the canines are elongate, the premolars are small and sometimes reduced in number, and a constriction is usually present between the lateral and medial halves of the upper molar. The carnassials are developed. The second lower molar, if present, is reduced to a simple peg.