An elephant seal's giant nose works as a water-recycling rebreather
A bull elephant seal can weigh 4,000 kilograms, ten times a female, and sports a drooping trunk-like nose. That nose was long thought to amplify threats. It actually recaptures moisture from each breath, letting males survive weeks on the breeding beach without eating or drinking.
Two species make up the genus Mirounga. The northern elephant seal ranges along the Pacific coasts of Mexico, the United States and Canada, breeding as far north as Race Rocks off Vancouver Island. The larger southern elephant seal lives on sub-Antarctic islands such as South Georgia and Macquarie and on coasts from New Zealand and Tasmania to South Africa and Argentina's Peninsula Valdés. Both were hunted almost to extinction for lamp oil by the late 1800s, and both have since recovered.
They are the biggest seals of all. Southern bulls typically reach 5 metres and 3,000 kilograms, while cows are about 3 metres and 900 kilograms. Northern bulls are somewhat smaller, though they tend to have a bigger proboscis and a thick, reddish chest. Pups can weigh 36 kilograms at birth. Elephant seals spend around 90 percent of their lives underwater hunting and can cover 100 kilometres a day at sea.
As true seals, they lack external ears and have reduced limbs, which streamlines them in water but makes land travel awkward, since unlike sea lions they cannot swing their hind flippers forward to walk. Their broad hind flippers do the propulsion instead. The male's nose is a secondary sexual trait, but its internal cavities also reabsorb moisture from exhaled air, crucial during a mating season spent fasting on shore.
John Edward Gray named the genus in 1827, reportedly from an Australian Aboriginal word, though which language it came from is unknown. The group evolved in the Pacific during the Pliocene. The oldest undisputed fossils come from New Zealand's Hawke's Bay; supposed older teeth from South Africa are now thought to belong to a toothed whale.
Source: Elephant seal
