The Southern Elephant Seal Bull (Mirounga leonina).

Or – Big Bad Blubbery Bulls.

Big fat blubbery elephant seal bull

A huge fat angry looking Elephant Seal Bull (Mirounga leonina) at Macquarie Island

These enormous mammals are a sight to behold. I recall the first time I came across a male Elephant Seal bull on one of the islands off Casey in Antarctica, I was impressed at the size, and that was only a young bull, not yet his full size.

Later I was to spend a full year living amongst these incredible mammals, and to witness their seasonal cycle. It’s incredible that one can become so attached to something as big, fat, loud, ugly and smelly, however it does happen. I was truly blown away when I saw just how big these seals are! (See the YouTube video below)

One way to tell whether an Elephant Seal is young or old is by the size of their proboscis (nose) and their scarring from fighting, particularly around the neck area. A fully grown male has a very large bulbous nose and usually a lot of scarring; as seen in the photo below.

Old elephant seal bull on the beach with large proboscis

This Elephant Seal Bull has a large proboscis and a lot of scarring from fighting.

The unusual proboscis is used to blow air into the throat which resonates and creates loud vocalisations. These roars are used to intimidate the other males and to state their size and strength to his opponents. This is usually enough to deter another male from encroaching on the harem or territory, however at times the disputes are resolved by body blows to each other, sometimes to the death.

Elephant seals rely on their blubber, or fat, for warmth. The fatter these seals are the happier they are. The southern elephant seal is the fattest or largest of all the worlds seals, with the males averaging 3000 – 4500 kg.

For a male, being big and fat increases his chances of mating. Elephant seals are highly polygamous, the bulls mate with as many females (cows) as possible. The larger or fatter males maintain territory on the beach. The females which come ashore in those territories make up his harem. He is the Beachmaster, and he will defend that territory against rival males. They also displays an unusual sexual dimorphism where the males are up to ten times larger than the females, which average 400 to 700 kg in weight.

Males, come ashore twice a year; to molt and to breed. During both periods they fast, loosing considerable proportions of their fat or blubber mass, which they will replace when they return to the sea for feeding.

Information from Steve Wall @ Macquarie island

© 2011, Haich. All rights reserved.

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