Elephant seals take their name from the large proboscis of the adult males (bulls) which resembles an elephant's trunk. The bull's proboscis is used in producing extraordinarily loud roaring noises, especially during the mating season.
More importantly, however, the nose acts as a sort of rebreather, filled with cavities designed to reabsorb moisture from the animals' exhalations. This is important during the mating season when the male seals rarely leave the beach to feed and therefore must conserve body moisture as they have no incoming source of water.
Bulls of both the northern elephant seal and the southern elephant seal reach a length of 16 ft (5 m) and a weight of 6,000 lb (2,700 kg) and are much larger than the cows, which typically measure about 10 ft (3 m) and 2,000 lb (900 kg).
The largest known bull elephant seal weighed 11,000 lb (5,000 kg) and measured 6.9 m (22.5 ft) in length. This makes the elephant seal the largest member of the order Carnivora.