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.

Bulls communicate

June is a month of transition, when seals of a wide range of ages mix on the beach. Adult bulls are starting to arrive to join the juvenile seals and adult females that have dominated the beach since April. The bulls, fat from feeding in the north, now take over the beach for the summer.

Molting is the annual peel-off of their hair and top layer of skin. It makes them look ratty, but it’s normal. The old hair is brown and tattered. The new skin, with newly emerging hair, is pearly gray.

Males are returning, with some of their hefty blubber restored after the 100 days they spent without food during the breeding season. Males feed along the coast of Alaska. They swim north from Piedras Blancas, covering 60 to 75 miles a day, after the winter breeding season is over. They mostly forage for bottom-dwelling prey along the continental slope of Alaska. They return swimming across the ocean, directly to the California coast.

Adult bulls are among the largest seals, at up to 5,000 pounds. They are surely dramatic, showing off their prominent noses and pink chest shields. Their guttural bellows echo against the bluffs.

New research on what their bellowing means shows that their calls have changed since the 1960s. Pioneering elephant seal researcher Burney Le Boeuf found the seals at different locations bellowed at different pulse rates. In effect, they were communicating in different dialects. That was the first time dialects had been identified in non-human mammal communication. When UCSC researcher Carolyn Casey re-analyzed Le Boeuf’s recordings and compared them to new recordings, she found the dialects had disappeared, but more individual variations had developed.

Geographical dialect may have disappeared as the population expanded and seals mixed more among beach sites. But their calls got more complex. Those individualized vocalizations help the seals know who is who.

Each individual male has his own unique vocal signature. Each bull knows his adversaries as individuals. They recognize each other by their calls, and remember who won the battle the last time. That simplifies seal life, in which dominance is important: No need to fight again. They’ve settled who won.

Bulls can keep track of 25 to 30 other bulls that way.

Without these new signatures, “it would be really difficult to distinguish everyone,” Casey said in an interview with The Atlantic magazine.

No need to fight during the summer molting months anyway. As important as it is for bulls to reign as dominant, to breed with as many females as possible, conserving energy is important, too. During the breeding season, a bull may go as long as 100 days without food. The bulls on the beach now are saving the blubber they’ve regained since the breeding season. They’ll rest on the beach for a few weeks, then return to the ocean to forage and bulk up even more, for the breeding season that begins in December.

Look for big, resting bulls on the beach. That 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. Females can live into their 20s.

Ask a Friends of the Elephant Seal docent, a guide in a blue jacket to touch some of the shed skin. They carry samples to share with the public. Most enjoy handling it, but some prefer only a cautious touch.