The leopard seal (Hydrurga leptonyx), also referred to as the sea leopard, is the second largest species of seal in the Antarctic(after the southern elephant seal). Along with all of the other earless seals, it belongs to the family Phocidae, and is the only species in the genus Hydrurga. The name hydrurga means “water worker” and leptonyx is the Greek for “small clawed”.
The leopard seal is large and muscular, with a dark grey back and light grey on its stomach. Its throat is whitish with the black spots that give the seal its common name. Females are slightly larger than the males. The overall length of this seal is 2.4–3.5 m (7.9–11.5 ft) and weight is from 200 to 600 kilograms (440 to 1,320 lb). They are about the same length as the northern walrus, but usually less than half the weight.
Its front teeth are sharp like those of other carnivores, but its molars lock together in a way that allows them to sieve krill from the water, in the manner of the crabeater seal.