The northern elephant seal is the largest of the northern hemisphere's pinnipeds. The adult male, with his pendulous snout, averages 2 t (2.2 tn.) and is about 4 m long (13 ft.). The females are smaller, about 2.8 to 3 m long (11 to 12 ft.) and decidedly more svelte, weighing around 700 kg (1,500 lb.).

Much sought-after by commercial sealers for their fat, these animals were driven to the brink of extinction; by the early 1900s, only about 100 were left. After years of complete protection the northern elephant seal is a conservation success story. There are more than 100 000 now, and many of the former breeding sites have been repopulated.

Elephant seals are renowned for their deep dives. Their main food, squid and bottom-dwelling fish, is usually found at depth. They are sometimes preyed upon by killer whales.