The Southern Elephant Seal (Mirounga leonina), one of two species of elephant seal, is not only the most massive pinniped, but also the largest member of the order Carnivora living today. The seal gets its name from its great size and the large proboscis of the adult males, which is used to make extraordinarily loud roaring noises, especially during the mating season.

This info and more at; http://en.wikipedia.org/wiki/Southern_Elephant_Seal