Skin molt

 All seals, all the time

Molting seals shed their skin

The Piedras Blancas elephant seal beaches are full of seals in May. It’s the busiest time of the year. All the females who had pups during the breeding season are back, along with all the male and female seals who are not yet fully mature.

Of the full herd, only this year’s pups and the mature bulls are not on the beach. They are on their migration, feeding before they return later in the summer and fall.

Feeding during the short migration

The females are looking good, fat from two months of feeding in the open ocean. Recent research showed that these seals, who departed in February thin from not eating during the breeding season, spend almost all their time after they leave the beach feeding. They average less than an hour and a half of sleep every day, diving constantly to devour enough fish to gain the weight they need.

Using electronic technology to measure jaw movements and record video of what the seals were eating, the researchers found the females relied on small fish in the open ocean. They dove to 1,300-2,000 feet, a zone where these small fish, which in total comprise most of the ocean’s fish biomass, are plentiful. The females snap their jaws between 1,000 and 2,000 times a day, to catch fish that weigh less than half an ounce.

These female seals are the only large animals down there, feeding on these fish. The males are simply too big to make a living on small fish, so they stay closer to the coast and hunt bigger prey on the ocean floor.

The downside is that it takes all day, every day, for these half-ton seals to eat enough to make up for the weight they lost during that month or more they spent on the beach, giving birth and nursing their pups.

The research was based on the Ano Nuevo colony. The research team includes Patrick Robinson, director of the Ano Nuevo Reserve, and UC Santa Cruz assistant professor Roxanne Beltran, who will discuss their work in the future at a public event in Cambria.

Molting

They return, with that sleek load of blubber, in May. They molt their skin, which we can see. What we can’t see is that their bodies are changing internally, preparing for the next pup to be born next winter.

This annual event gives them new skin to face the coming year. You can see the difference between the old, brown skin and the pearly gray new skin. As the hairs grow, their appearance will go back to shades of brown.

Young seals

The young males and females on the beach loll in the sun while their skin peels off. Young males spar, in the sand and in the water. They bark their complaints about being shoved around in the crowd.

Look for young males with noses just starting to grow. They are typically more active than their quiet mothers.