Welcome back, Bulls!

It’s their turn on the beach

Hefty bulls take over the beach during the summer months, to molt their skin. The younger bulls stage battles, but mostly bulls rest and let their skin peel off. Unusual scars attest to the dangers of seal life in the open sea. Cookie cutter shark scars, not fatal, are common. I comfort myself with the thought that blubber doesn’t have many nerve endings.

It’s their turn to take over the beach, from the females and juveniles who occupied it during the spring for their molt. The juveniles will return in the fall, but the females won’t come back on land again until January, when they come back to have their pups.

During the summer molt, the bulls fast, taking no food and living instead off their blubber. Their sex organs regress, and stop producing sperm and sex hormones. They have no urge to dominate and fight.

It’s good viewing for visitors, who always enjoy seeing the big males. Adult elephant seal bulls may weigh over two tons, and be more than fifteen feet long. Bulls, with their floppy noses and pink chest shields, are always crowd pleasers to the influx of summer visitors on a classic Highway 1 road trip.

When he lies down, you can see the San Luis Obispo county elephant seal’s pink chest shield, a sign his skin has starting molting. The young seals around him are almost finished getting new skin.

Foraging                                                                                                                                                                   The bulls have been at sea, foraging and regaining blubber, for about four months. They were at their lowest weight when they left the beach after the breeding season. They don’t eat much while they are traveling to and from their destination feeding areas, along the Oregon and Washington coast, or as far north as the Gulf of Alaska and the Aleutians.  It may take a month or longer each way.

Thin at the end of breeding season. 

They travel sixty to seventy miles a day. Like females, they travel forward by diving down and returning to the surface, transit dives, always moving forward. It’s not a straight line through the water. Transit dives may cover three quarters of a mile. On very deep dives, three thousand feet, the seal may be exploring for prey. He’ll eat whatever he finds.

That leaves them about sixty-six days at the foraging destination to feed and gain weight. They make up for it by non-stop gorge feeding. Bulls actually feed for only about a quarter of the days in a year.

“They alternate between extreme feasting and extreme fasting,” Bernie LeBoeuf writes in Elephant Seals: Pushing the Limits on Land and at Sea.

Bulls seek the continental shelf to feed. They eat bigger fish such as skates, rays, ratfish, small sharks, hagfish, and cusk eels.

Each male forages in a single area that is relatively small, near the continental shelf break.

Molting

Bulls molt similarly to females: the new skin layer has formed under the old skin. As the new skin develops, the blood supply to the old skin gradually declines. The outer skin, the cornified layer, dies and peels off. It starts peeling off around the eyes and ears, old scars, and other body orifices. Then the belly and sides and back peel off.

The new skin and hair underneath is gray. The hairs are short, but soon stand up and grow longer. Look for pearly gray seals next to brown and tan seals.

Ask a blue-jacketed Friends of the Elephant Seal docent to see and handle some of the shed skin.

The seals are aware of the viewers, but don't seem to mind. 

Male development

Subadult males join the adults. Young males adjust their molting migration as they mature, from May and June with the juveniles to the later summer months. They are growing into their eventual breeding migration.

For the summer, males at all stages of subadult development are on the beach along with the mature bulls. Subadult males, from puberty at around age four to eight years old, are more mature than juveniles, from one year old until they enter puberty. They may be sexually mature, but are not likely to mate successfully because they are not yet dominant over more mature bulls.

Subadult seals are classified by the size and development of their nose. That nose, technically proboscis, starts growing at around age four, Subadult 1. As the nose develops, at age five they are Subadult 2, age six, Subadult 3, age seven, Subadult 4. Any bull older than eight is an adult.

The chest shield, crinkled calloused skin that protects the area where bulls rip and tear at each other, starts developing around age six.

Adults, age eight and older, have fully developed noses with a deep notch across them. It droops and curls under on the sand as the seal rests. Because it continues to grow throughout the seal’s life, it may be very long.

The chest shield gets progressively more gnarly. By age eight, it may encompass the seal’s neck from one side of the body to the other, as far up as level with the eyes when the seal is lying down. That large chest shield is considered a mark of being fully adult.

Both nose and chest shield continue to grow throughout the seal’s life. They are a rough gauge of age after the males are four years old.

Scars

Over the years, these senior seals have accumulated the scars that give silent witness to the drama of their undersea life. I saw a couple of white shark bite scars, and lots of cookie cutter shark scars. Cookie cutter sharks are small sharks, 18 inches or so, that bite into the blubber, twirl around to take a plug, and leave behind that distinctive circular scar.

Some seals have multiple cookie cutter shark scars. Maybe the sharks swim in schools. 

Tags

Some elephant seals have colored flipper tags. Typically, they are tagged as weaned pups. Only a small percentage of pups are tagged. The colors correspond to the rookery where the pup was born. Piedras Blancas tags are white, and that’s the color most frequently seen on the beach. Elephant seals are inclined to return to the beach where they were born.

Not always, though. Seals with green tags, from Ano Nuevo, and other colors show up. Take a photo, enlarge the tag to read the number, and report the seal to FES. It’s always interesting to know who is here and where they have been.

Seals that have been rescued and rehabilitated get orange tags. No one has seen Rabble, the entangled seal who was released from the plastic packing strap around his neck in May, since that day. He has two orange tags now, where ever he is.