Recently weaned elephant seal pups rough-housing.
Natural History of the Northern Elephant Seal
The natural history of the pinnipeds is not an open and shut book. Several theories have been put forth, but this is the most widely accepted one:
The elephant seal (both northern and southern) is a member of the pinniped family, a large order of marine mammals, which of course means they are warm blooded and breath air. The origin of the word "pinniped" should tell you something about this order of animals. It is a combination of the Latin words for "feather" and "foot", literally meaning "feather-footed one". Another large order of marine mammals everybody is familiar with are the cetaceans, or whales and porpoise.
What's interesting about this is the land mammals that returned to the sea and later became pinnipeds were animals like bears, otters, dogs, etc. This evolution is very evident in the seal's skeletal and flipper structure. On the other hand, it was the hoofed animals (deer, pigs, cows, etc.) that returned to the sea and evolved into the whales and porpoise. Interesting, hunh? If you let your mind wander really far, this might even make sense.
How many "flipernails" does that guy in the background have?
What about those Pinnipeds?
Pinnipeds are further broken down into three families: Odobenidae, Otariidae, and Pocidae. The elephant seal is a member of the Phocid (pronounced "f-oh-sid") family. The Phocids are also known as "true seals" or "earless seals" and are thought to have evolved from an otter-like creature that returned to the sea about 25 million years ago. Phocids swim by expanding their powerful rear flippers and swimming like a fish. Their front flippers are not as strong and merely provide directional stability while swimming. These characteristics make them not all that well adapted to moving around on land. They have to sort of drag themselves around like oversized inchworms (very oversized).
Earless seals do have ears but they are internal. There are just a couple tiny holes on top of the head. Internal ears and sex organs, and a thick layer of blubber make elephant seals very streamlined which probably helps them fall through the water column with ease while doing their deep diving routine.
Spread out rear flippers, looking like a tail of a fish.
Elephant seals are the largest of the Pinnipeds. For that matter, Pinnipeds are a sub group of the order Carnivora (meat-eating mammals), of which elephant seals also are the largest member. They exhibit extreme sexual dimorphism (the male is much larger than the female). Their highly competitive and polygamous breeding behavior is probably what contributed to the males evolving to the size they are. Through the millennia the largest and most aggressive males were the ones passing on their genes.
What about that nose?
How the males developed that giant nose is subject to debate. It's primary purpose appears to be sexual. I would assume that most often it's other males who are aware of the size of their surrounding buddies' noses rather than the females being attracted to the dude with the biggest shnoz, but who can tell? So it too is perhaps the result of the biggest males passing on their genes.
The nose also has a lot of blood capillaries throughout, perhaps lending itself to heat and moisture retention. This could aid a large male in making it through the long fast during the breeding season. And it could help during long and deep dives, but the females can dive long and deep as well so... You make the call.
This bull's tired of all this discussion about his big nose.
What about the other pinnipeds?