Big bulls at rest – or not

Summer on the beach

Summertime, and the living is easy for elephant seal bulls. They are on the beach, molting their skin. That makes July a great time to observe some of the finer points of elephant seal appearance and behavior.

Bulls return from their foraging migration in the summer, plumped up after that 100-day fast during breeding season in the winter. Gaining a ton or so of blubber is a big job. They’ll fast on the beach for six weeks or so, living on that blubber. After they finish molting and have their new skin, they will go back to the ocean to continue foraging until December. Then they’ll be ready for the breeding season, at top form and top weight, as much a two and a half tons.

For bull seals, it's always a good day for a fight.

 They are a palette of camouflage colors, from nearly black, when they emerge wet from the ocean, to light tan on their bellies. The new skin looks pearly gray, because the individual hairs are just emerging. The dark backs and light underside are an example of countershading, a form of camouflage from predators. To predators looking up from below, the light belly blends with the bright light of the surface. To predators looking down from above, the dark back blends into the dark depths.

Ask a blue-jacketed Friends of the Elephant Seal docent to show you a sample of shed skin. You’ll see why elephant seals weren’t hunted for their short, stubbly fur. They don’t have the lush coats of otters and fur seals, which rely on fur to keep them warm in cold water. Seals have their blubber for that.

The resting seals give visitors the opportunity to compare noses and chest shields, important characteristics for bulls. The nose, (technically, proboscis), and the chest shield, grow throughout a male seal’s maturity, starting around age five, so they are rough indicators of his age. Bulls can live to be 13 or 14.

This group of seals shows the differences between noses and chest shields. 

Look for a pendulous nose with a crease across the top. Chest shields can extend from the middle of the chest to above eye level. Younger seals have a smooth nose. The chest shield may be barely visible, just starting to develop on the seal’s front.

Subtle points, but they are indications of older age among the seals.

Summer isn’t all R&R for seals. Some pick fights, and spar across the sand and into the water, but most rest comfortably side by side. They won’t do that during the breeding season, when they have to be wary of any rival.

Without females to fight over during the summer, the only prize is dominance. That may serve them later in the year, when a win will be remembered and future fights avoided during the breeding season. Better to conserve their energy for more important things then.

They have earned a few weeks’ rest on the beach. Whether traveling or feeding, seals are constantly diving. They breathe at the surface for two or three minutes, then head to 2,000 feet or deeper. It’s not a direct swim along the surface. Day in and day out, it’s up and down. No wonder they are snoring in the sand.