Weaning

Pups fill the beach

All stages: newborn, nursing, and weaned

There’s a lot to see at the Piedras Blancas elephant seal viewpoint in January and February, the breeding season. Pregnant females arrive at the Piedras Blancas viewpoint beaches daily. They join the mothers already there, nursing the pups born in the past month. The females congregate in groups, harems, presided over by a beachmaster, who is vigilant about defending his rights. Other bulls challenge him. Lots of activity, constant movement and drama.

Two male elephant seal take the battle into the ocean

 at Piedras Blancas tookery. The one on the right began the fight with bleeding wounds on his chest shield. 

Pups

The first ones born, in December, are already being weaned, and their mothers leave on their short migration. Gingerbread, the first pup born December 12, is a fat weanling.

Weaned pups congregate in groups called pods, out of the main breeding areas, along the base of the cliffs. Look for rotund seals shedding black fur. They shed the black coat they were born with after they are weaned. They grow their first countershaded coat, darker brown on the back and lighter on the belly.

As the mothers wean their pups, after nursing for about a month, they come into estrus, heat, and are receptive to breeding. That’s when the beachmaster’s wait, since arriving on the beach in November or December, is rewarded.

This mother is ready to wean her pup.

Females mate with bulls before they leave the beach. Mating can be noisy, with the female barking and flapping around. Other bulls may take interest and chase the bull attempting to breed. Fights break out. One vicious battle last weekend went from beach to the ocean, with both bulls eventually returning to the beach, although with more separation between them.

The seals mate on the beach, X-rated. The most dominant bulls get to breed, but they are regularly challenged by other bulls. That’s when they may come to battle.

Beachmasters at the top

They fight for dominance. The most dominant bulls, the beachmasters, have breeding rights with the females, usually a harem of about 30 at Piedras Blancas. Researchers estimate that only about one percent of males born ever get to breed. So there’s a lot at stake.

Each bull has a unique call. Bulls recognize each other by call much more readily than by sight.

Bulls approaching one another bellow to show the other who they are. If dominance has been

established, watch one bull back away. If the bulls are strangers they will continue to

approach. They may rear up to show their size, but if neither backs off it will get physical until dominance is determined.

That helps them avoid battling bulls they have fought before. Once a match is settled, the bulls accept that result and avoid each other in future. If they’ve fought before, no need to fight again. They establish themselves in the dominance hierarchy. A bull may remember as many as 50 opponents. They can remember who beat who for years.

Dominance interactions are clear to see from the bluff. The dominance hierarchy actually helps reduce conflict on the beach, by settling conflicts before they come to a fight. One bull challenges another, and one of them backs down.

Fighting uses a lot of energy. These seals need to be able to survive, and fight and mate, for 100 days or longer, relying only on their blubber, without food. Having a lot of blubber helps, but eventually any seal will be depleted. Conserving energy extends the range of a seal’s vitality during the breeding season.

Sneaking into the harem

It’s a tough time for the bulls. Dominant beachmasters have to be vigilant. Look for “sneaker” bulls, who hang around the fringes of the harem. They seem to camouflage themselves among the mothers, who are busy with their pups. They are attuned to the beachmaster, waiting for his attention to be diverted by a direct challenge. As he galumphs across the beach in battle, the sneaker bull moves forward among the females and tries to mate.

Females typically bellow and complain, but the beachmaster may be too deeply involved in the battle to respond. 

This female looks back at the bull who is approaching her. 

Less dominant bulls may leave the breeding beach entirely. In past years, they have come to rest on other local beaches, but this year some are taking refuge on the north beach at the rookery. It’s been fully inundated during high tides, so few pups are born there. It’s a beach these defeated bulls can have to themselves. When a beachmaster is defeated, he loses all status, and drops to the bottom of the hierarchy.

Pups carry on

In the midst of this conflict, pups need to nurse to gain weight and grow. They may get separated from their mothers. They may starve if they can’t find each other and reunite. Pups separated from their mothers may find another mother willing to let them nurse. About 80 percent of pups nurse on more than one mother before they are weaned.

Last weekend, we watched one pup search for his mother, dragging himself along the beach. One mother turned and bit him on the head, then the body, as he squealed in fright and pain. He moved on, and another mother bit him. He called and called, and eventually a female recognized his bark, and came thundering up the beach. They touched noses and settled down together.

The connection seemed a bit uncertain, and those of us watching hoped that the pair would stay together.

One pup at a time

Elephant seal mothers have only a single pup. Since they don’t eat while they are nursing, they don’t have adequate reserves to feed multiple pups. It’s common for pups to nurse on mothers other than their own, though. Some mothers tolerate it better than others. Often mothers have several pups around them. Only one is hers.

She can't be mother to both, but she seems accepting. 

Mothers whose pups don’t survive may adopt a pup, or at least be willing to let a hungry one nurse. The experience may help inexperienced mothers become better mothers.

Not all pups survive, and mothers sometimes fight over a pup. Mothers without a living pup still have milk, so there’s a net surplus of milk on the beach. The milk changes as the pup develops, so mothers and orphan pups may be mismatched. Pups and mothers need to find each other despite the confusion.

Drama on the beach

Although conflict and chaos churn across the beach, the seals find enough peace to accomplish their birth and mating season. It’s a time of unfolding drama, from one crisis to the next.

One foggy morning, I met up with a Facebook photography group, The Nature Photography Group of the Central Coast, to learn how to take better photos and provide the photographers with pointers about what the seals are doing. Check out their Facebook page for more photos.

Several visitors from the Morro Bay Bird Festival also visited the bluff. One pointed out an Ancient Murrelet floating over and under the waves, so named for the white feathers circling its head, like the laurel wreath of ancient Roman statemen. This tiny bird dives underwater to catch fish.

Always something new to see along the coast, part of the Monterey Bay National Marine Sanctuary. Take lots of pictures, and bring home those stories to tell.

Christine Heinrichs is the Monterey Bay National Marine Sanctuary Advisory Council SLO At-Large member. Her elephant seal column won first place from the National Society of Newspaper Columnists in 2024. Follow her on Facebook, Bluesky, LinkedIn, and Substack.

 

First pup Gingerbread is now on the beach!

The Piedras Blancas elephant seal breeding season hasofficially started

The air crackled with excitement all week. Docents messaged each other, watching over a pregnant seal squirming on the beach. Soon, soon, the first pup would arrive.

Tis the season! After a long day on Thursday, December 12, Gingerbread was born overnight. Sex undetermined, but mother and pup are resting well.

FES Docent Jim Mentgen was the first to see and photograph the pup, so it was his privilege to name the pup. Gingerbread has the whiff of the season, along with a playful image of sugarplums dancing in our heads. Nineteen other docents shared honors for guessing the date of the first pup arrival. It’s an informal lottery among FES docents.

Gingerbread greets his mother.

Welcome, mothers and pups!

Gingerbread is the first of over 5,000 pups that will be born between now and February along the beaches of the Piedras Blancas rookery. The rookery includes the boardwalks of the viewpoint, and extends from north at the light station to about a mile south of the viewpoint.

Pregnant females will continue to arrive, one by one. They settle on the beach for a few days and then give birth to their pups.

This is the time of year when visitors may witness a pup being born. Although many pups, like Gingerbread, are born at night, pups can be born at any time. It’s a breathtaking experience for anyone. It never gets old for experienced docents, and it’s thrilling for visitors who are fortunate to be in place when a pup is born. An experience to take home and tell their friends!

Looking through my records last week, I found that the first time I saw a birth was in 2009. Every birth is unique, always exciting.

When will a pup be born?

It’s hard to predict – experienced docents held their breath all day Thursday, and the pup was born later. Look for a female seal digging out a “saddle” by tossing a lot of sand on both sides. That sometimes indicates that she will soon give birth.

Or not. Nothing is certain in wildlife viewing. As soon as you’re paying attention to one seal, another down the beach will squirt out a pup.

Bring a chair. Be patient. The weather is warm and pleasant. No restrooms at the viewpoint, but at the Hearst Memorial Beach at San Simeon Cove. Plan to take a break. The Monterey Bay National Marine Sanctuary Discovery Center at the cove is now open, 10 am – 4 pm, Thursday through Sunday. New interactive exhibits, listen to whale sounds and view live plankton collected from the San Simeon Pier. Get the full coastal experience!

A gull hangs around a nursing pup to steal milk.

Gull announcements

As with other placental mammals, a birth is followed by the afterbirth, the placenta. In the case of elephant seals, gulls screetch and swoop around to consume the afterbirth. They are the beach clean-up crew.

It feels anticlimactic, like you have missed the Main Event, but follow the gulls to see the newborn and mother make their first barks and sniffs to each other.

Pups and their mothers recognize each other by their vocalizations and their scent. That gets established within the first couple of days of life. It’s important, because a pup separated from its mother may starve and die. Maternal separation is the most common cause of pup death.

While all pups are vulnerable, most pups nurse on more than one mother at some time. Early in the season, only a few mothers, well separated, occupy the beach. Later, when the beach is crowded with mothers and pups, some mothers may nurse more than one pup.

Not every pup survives, although over 90 percent of the pups at Piedras Blancas do. A mother whose pup dies may let other pups nurse, or may adopt another pup. Or she may stay a few days and leave. Whether she mates or not is not yet established.

With so many mothers and pups on the beach, any mother and pup may get confused.

One pup per mother

Gingerbread is the standard-issue pup. He – or she, hard to tell from a distance – is about three feet long and weighs about 75 pounds. No multiple births. Mothers don’t eat during the month they spend nursing. They don’t have enough blubber reserves to nurse more than one.

During that month, the pup gains weight rapidly, up to about 300 pounds. The mothers stay with the pup the entire time. They don’t leave the pup to feed in the ocean, so they lose a lot of weight, about a third of their body weight.

Gingerbread’s mother is nice and fat. She’ll need it.

Pus can't swim well, so they need to sstay above the high tide line.

Above high tide line

Gingerbread is in a good position on the beach, above high tide line. That’s an important consideration, because King Tides, the highest tides of the year, will return January 2 and 3, and there will be other high tides. Gingerbread’s timing is good, with three weeks to nurse and gain blubber before the tide comes crashing up the beach again.

Gingerbread can’t swim much yet. Without blubber to stay warm, and able only to paddle a little in the water, pups can drown.

Gingerbread’s mother appears to be mature, probably an experienced mother who has raised other pups. She may even be among the Supermoms, one of the six percent of the females who eventually give birth to 10 or more pups during their lifetimes. Supermoms account for more than half (55 percent) of the total pups born. Supermoms live longer, breed more frequently, and raise bigger pups.

Bernie LeBoeuf, now professor emeritus at UC Santa Cruz, led a research team that identified Supermoms in a 2019 scientific paper. 

Gingerbread’s mother chose a nice dry spot on the south beach. Mothers who give birth at low tide don’t realize that their pups may be at risk later, when the tide comes in. Most of the north beach at the Piedras Blancas viewpoint was inundated with waves during December’s King Tide. Some pups born in the few areas behind rocks could be safe, but any born on the open sand may be washed away.

Share King Tide photos

You can take photos and submit them to the California King Tides Project. Think about taking photos in areas that are subject to flooding and erosion, and of places where high water levels can be gauged against familiar landmarks such as cliffs, rocks, roads, buildings, bridge supports, sea walls, staircases, and piers.

Taking and sharing photos documents the changes in ocean level and how those changes are affecting the coastline.

Christine Heinrichs is the Monterey Bay national Marine Sanctuary Advisory Council SLO At-Large member. Her elephant seal column won first place from the National Society of Newspaper Columnists in 2024. Follow her on Facebook, Bluesky, LinkedIn, and Substack.

Bulls ready to roar

Biggest bulls return for the breeding season

Mature bull elephant seals, foraging at sea for the past ten or twelve weeks, will start arriving at Piedras Blancas any day. They are at their biggest and loudest now. They are ready for action. The bulls will be on the beach until March. Great holiday viewing for visitors!

They are preparing for the breeding season, the high point of the year. The bulls are ready for battle when they arrive. They are in prime condition, with enough blubber to carry them through. They may not eat again until March, as long as 120 days.

This mature bull annunces his arrival on the beach at Piedras Blancas.

Arrival

The first bull usually arrives around Thanksgiving. It may look quiet at first.

Look for a big seal surfing in, arising from the waves as a monster from the deep. After a few galumphs up the beach, he stops. Without the buoyancy of water supporting all that blubber, he feels his full weight under gravity. He’s making the transition from life underwater to life on land.

Juvenile seals are still on the beach, lingering from their fall haul-out. They’ll soon get the message: It’s time for the Big Boys to take over. Some may find places on the beach to continue resting for a while. They may benefit from observing the adult social order. In a few years, they will be part of it.

Preparing for breeding season

The bulls have been feeding on fish and squid along North America’s continental shelf since August. They gained as much as 28 pounds a day. Leaving their feeding grounds, the bulls stopped eating and swam directly from as far north as the Aleutian Islands to return to southern beaches.

This is the long fast of their year. They can’t leave the beach to feed. The good feeding areas are hundreds of miles north. Besides, they need to stay on the beach to defend a harem until the females are ready to breed, a month after they give birth. That can extend into March, as females give birth in January and February.

It’s all worth it to them. Beachmasters, 12 or 13 years old, have only one or two good years at the top. They fight to take advantage of their power.

This younger bull is wiling to challenge older bulls for dominance.

Dominance hierarchy

On the beach, even before females arrive in December, they threaten and fight each other to establish the beach dominance hierarchy. Although threats and fighting establish the dominance hierarchy, dominance actually helps reduce conflict in the rookery. Bulls recognize each other’s call, and remember who won. They don’t need to fight again.

Viewers can see the dominance hierarchy acting out on the sand. One bull vocalizes a deep, grunting threat to another bull. All the bulls hear, and start clearing away, which is called displacement. One bull may respond by calling back, or by raising up and coming across the beach for the fight.

That’s when the titans clash. Chest to chest, biting with those big, two-inch, canines. The chest shield, torn and battered, drips blood. No quarter is given.

Most fights are brief, less than a minute, but some last half an hour, exhausting both fighters. They may cross the sand and continue the fight into the water.

The fight ends when one gives up and retreats. The winner my continue chasing him, biting his back. Take that!

This senior bull -- note the long proboscis, with a crease -- has seen years of breeding seasons.

Females soon follow

A solitary female or two may arrive in late November, but they will certainly be on the beach in December. They give birth within a few days of arriving on the beach. Look for the first pup in mid- to late-December.

That’s when the important part of the dominance hierarchy kicks in. Bulls guard their harems of females as best they can. It’s always imperfect, with subdominant bulls constantly challenging the beachmaster’s top position, or simply trying to get away with mating with a female on the edges of the harem.

Only the dominant bulls, the beachmasters, will get to breed freely, without threat by more dominant bulls. By the peak of the breeding season in January and February, beachmasters will reign over harems of 30-40 females on Central Coast beaches.

King Tides

Winter brings the highest tides of the year to the West Coast, King Tides. They are predictable, happening when the sun, moon, and Earth align to exert the greatest gravitational pull on the ocean. This year they will occur on the mornings of November 6, December 4-6, and January 2-3.

High tides may affect pups born within that high tide zone. Females who choose higher ground are more likely to raise their pups successfully to weaning. The most dominant bulls also stake their claim over these sections of beach.

California Coastal Commission invites the public to submit photos that illustrate how far the water 

First Bull Arrival contest

Friends of the Elephant Seal holds a contest every year, to guess when the first bull will arrive for the breeding season. Enter the First Bull contest here!

The winner gets an FES baseball cap, and praise from FES members and elephant seal admirers. Which is the main point, and the most fun!

Visiting the Viewpoint

A visit to see the elephant seals is good holiday entertainment. Look for long noses and big pink chest shields on massive bodies. The nose, technically proboscis, and chest shield continue to grow throughout the seal’s life. Bigger is older.

Friends of the Elephant Seal docents in blue jackets are available every day to answer questions.

Check the live webcam to see what’s happening on the beach. Highway 1 remains closed to the north, at Lucia Lodge, due to the Regent Slide between the lodge and Esalen Institute.

Bring your camera.  Always open, always free. The viewpoint is located within the Monterey Bay National Marine Sanctuary, federally protected and held in trust for the world.

 

Marine Mammal Center tests HPAI vaccine

Cow vaccine could help protect rare Hawaiian monk seal

The Marine Mammal Center is testing Highly Pathogenic Avian Influenza vaccine on elephant seals at its Sausalito hospital. If it is effective in producing antibodies, TMMC plans to vaccinate Hawaiian monk seals. TMMC’s Ke Kai Ola monk seal hospital is on the island of Hawaii.

Hawaiian monk seals are classified as Endangered, with only 1,600 seals surviving. They are “one of the rarest seal species in the world, and conservation efforts are critical to their survival,” according to the TMMC website.

HPAI infects birds and mammals

HPAI, caused by the H5N1 virus, is highly contagious and deadly to several species. It has now infected species from wild birds to domesticated birds and even to mammals. That species-to-species transmission makes a threat to global biodiversity.

Monk seals may be vulnerable to HPAI, as may the Central Coast’s herd of Northern Elephant Seals. In 2023, HPAI wiped out Southern Elephant Seals in Argentina, killing more than 96 percent of the pups, 17,500, born there, and an undetermined number of adult seals. Scientists studying the colony say it may take 100 years for the colony to recover to the numbers it had in 2022, 18,000. 

Elephant seals try the vaccine

Veterinarians advised testing the vaccine on elephant seals first, to avoid risk to the already precarious status of monk seals. National Oceanic and Atmospheric Administration officials, which have jurisdiction over National Marine Sanctuaries, also consulted on the trial.

“Northern elephant seal research has taken tremendous steps forward over the past decade within our shared network of west coast research partners,” says Dr. Sophie Whoriskey, Associate Director, Hawai’i Conservation Medicine at The Marine Mammal Center. “This vaccine trial on six in-care elephant seal pups at our Sausalito based hospital is especially significant given the great risk that Avian Influenza actively poses for marine mammals.”

1. The Marine Mammal Center’s Dr. Dane Whitaker (left), Associate Veterinarian, and Sarah Pattison (right), Director of Hospital Operations, collect a blood sample from a northern elephant seal patient during an Avian Influenza vaccine trial at the Center’s Sausalito, California, based hospital on July 14, 2025. Photo by Bill Hunnewell © The Marine Mammal Center

The six young elephant seals who were in the vaccine trial had been rescued and were already at the hospital for treatment. The vaccine is one that was reformulated by Zoetis, a veterinary pharmaceutical company, from the HPAI poultry vaccine for use on cows. HPAI in California dairy herds has caused milk production to decline more than 10 percent, and caused other costly herd problems. HPAI has been found in poultry flocks and dairy herds in other states and countries.  

HPAI has also affected egg production across the country. The only strategy for controlling HPAI in poultry flocks is to depopulate, kill, all the birds in the infected flock. The reduced production of eggs and milk has had uneven effects on consumer prices. 

Vaccinated and Placebo groups

The vaccine trial started in July, when three of the seals got the vaccine, and three got a placebo. Some briefly developed hives, including one who got the placebo, but the hives lasted only a few hours. One of the seals in the placebo group died. That seal’s death is under investigation. The seals were already at risk, hospitalized for other reasons.

All else proceeded well, with no other symptoms in either group. In late August, the researchers collected blood samples from the five seals, who had all recovered from the problems that caused them to strand and be treated at the hospital.

Healthy and able to survive in their wild home, they were released to resume their elephant seal lives.

1. Veterinary experts at The Marine Mammal Center’s hospital and visitor center in Sausalito, California, carefully place a post-release tracking tag on the head of a northern elephant seal pup as part of an Avian Influenza vaccine trial on August 27, 2025. Photo by Bill Hunnewell © The Marine Mammal Center

The blood samples they left behind will be evaluated for HPAI antibodies. With those results in hand, the TMMC team will decide whether vaccinating wild monk seals is worthwhile.

“These individual elephant seal patients are providing valuable information to inform any future vaccination efforts to a related species, Hawaiian monk seals, that are endangered and at heightened risk due to their current population size,” Dr. Whoriskey said. “This initial pilot study has showed us encouraging signs that this vaccine is safe and we are in the early stages of measuring the antibody response produced to determine whether it is also effective. As more information is gathered post-release on these seals, consultation and discussions with study partners will be key in finalizing any future vaccination plans.”

If they decide to vaccinate the monk seals, the veterinarian will use a pole syringe to inject seals on the beach, to keep distance between the veterinarian and the seal.

“We may decide to go forward even if we’re not seeing a very strong antibody response,” said Dr. Whoriskey, noting that the seals did not have any pre-existing immunity to the virus. “Something is probably better than nothing in this case.”

Immunizing wildlife

Vaccinating wildlife sounds impossible, but Ventana Wildlife Society has done it for the Central Coast condor flock. The research team captures every condor at least once a year, to check for lead poisoning, so they have the birds in hand to vaccinate.

California Condor Photo Ventana Wildlife Society

Ninety-eight condors of the Central Coast flock, 89 percent, have received at least one dose of the HPAI vaccine, and 72 of those 98 have received the second, booster, shot, and are fully vaccinated. 

In Arizona in 2023, an HPAI outbreak affected 25 California condors, killing 21 of them. California condors are also classified as Endangered.

The main threat to condor survival as a species is lead poisoning from consuming lead ammunition in carcasses shot by hunters. HPAI is another threat to the condor species’ tentative recovery from near-extinction in the 1980s.

Juvenile seals take a break

Young seals rest, tussle, on the beach

Elephant Seal class of 2025 is arriving on the beach. The young seals, not yet in the breeding population, take over the beach. Adult females are out at sea, foraging, growing the pup that will be born in winter. Bossy bulls are away north, eating, putting on weight to dominate the breeding season. The young seals have the beach to themselves. It’s Juvenile Haul-Out.

This one hauled out over the Labor Day weekend, with a necklace of shark teeth marks scraped across the back of his neck. (Christine Heinrichs photo)

Last season’s pups, now the young of the year, left the beach after learning to swim and dive, in April. After practicing near the beach, at sea they had to master holding their breath longer and diving deeper, to 1,000 feet and more, to hunt for food. Fat weaned pups are buoyant at the start, and have to power down to find the fish and squid that are their prey. As they swim, their blubber becomes muscle.

Every migration they survive, they improve their diving and hunting skills. Two-year-old seals, veterans of four migrations, dive and forage as well as mature seals.

Young seals will fill the beach until late November, when the bulls start arriving for the breeding season. Not all the seals are on the beach the entire time. They come and go. It’s a good time to see seals of various sizes and levels of development. The males are too young to have a full trunk-like nose, but some have the beginnings of one. They are all elephant seals, on their way to maturity.

First migration

About half the young of the year survive this first migration. It’s not an easy journey. They could swim and dive when they left, but they had to navigate to feeding grounds on their own. They had to rely on instinct to hunt for food.

The young seals may have hauled out on other beaches along the way, as they migrated. Islands and remote peninsulas attached to the mainland present attractive new possibilities. Tagged females who later chose different beaches to give birth had stopped at those beaches as juveniles. They are “prospecting” for new, less crowded, locations, to have their pups. Young females are less likely to wean a pup successfully on a crowded beach, and those who fail at raising their  pups are likely to look for a different place the following year.

“The juveniles know what is available from their migrations,” Burney LeBoeuf wrote in The Quest for Darwinian Fitness: A Case Study of Elephant Seals. 

Juvenile Haul-Out

Juveniles were on the beach in spring to molt their skin, then lolled around until May or June, when they slipped away into the waves again. Since then, they have been growing and maturing. They are fat now, their smooth skins filled out.

The last bull left the beach over the Labor Day weekend. He and his brothers will be back in November for the breeding season. Bulls need to gain more blubber, to return at their biggest for the winter breeding season. They head straight for their feeding grounds.

 

In September and October, juveniles are arriving one by one. The immature seals take over the beach for six or eight weeks of rest. It’s a time of relative quiet, although thousands of seals will be on the beach. They sleep. Young males practice sparring, rehearsing for the serious fights of future breeding seasons.

 

These young males take each other on, but the other seals ignore them. (Christine Heinrichs photo)

On the beach, they pile on top of each other. Mostly it’s like a mound of puppies. Occasionally one takes offense, snapping his head around and roaring at the neighbor who rolled over on him. The disruption ripples through the assembled seal pile, then everyone settles back to sleeping again.

Elephant seals aren’t very playful. On rare occasions, I’ve seen one toss a piece of kelp around in a playful way. The young males spar with each other. The fighting isn’t as serious as when mature bulls battle over females during the breeding season, but it’s serious enough to them. Fighting is important to elephant seals – as adults, it determines who gets to breed and who doesn’t.

Visitors often remark on how much the tussling reminds them of their own teenage boys. It’s practice for adulthood.

One was sleeping peacefully when the other picked a fight.

It’s also exercise, which strengthens their bones. Because they spend so much time in the ocean, their bones lose density, a phenomenon that has been observed in astronauts when they spend time living in weightless conditions. Taking time on land twice during each annual cycle keeps them strong. As elephant seals return to land, subject to gravity’s greater pull, their bones get stronger. It’s another adaptation to their unusual life cycle.

No feeding time

Visitors expect to see the seals eating, or returning to the ocean for a daily meal, but there’s no Feeding Show at the viewpoint. These youngsters rest on the beach without interruption for a month or more. No need to hunt for food. They meet all their food and water needs from their blubber, fasting for the entire time.

Long fasts are common among marine mammals. Gray whales fast for six months while they are traveling south from the Arctic to their birthing grounds in Baja California. Elephant seals punctuate their months of constant eating with month-long and longer fasts. While they are on the beach, they don’t eat or drink.

They don’t drink at any time – what would they drink, in the ocean? Their large kidneys filter salt from the prey they eat and maintain their normal tissue balance.

Seals and Sharks

Each fall, adult and sub-adult White Sharks frequent the waters of the Greater Farallones National Marine Sanctuary, north of San Francisco, contiguous with the Monterey Bay NMS off the Central Coast.

Adult White Sharks are seen most frequently in the area between Tomales Point, Año Nuevo Island and the Farallon Islands, where there are lots of elephant seals and sea lions.

White Shark young of the year, the baby sharks born during the last breeding season, and juvenile White Sharks occupy the Southern California Bight and the coastal areas of central Baja Mexico, down to Vizcaino Bay. They start out eating fish, and as they mature, transition to eating marine mammals.

As white sharks get older, bigger and more mature, they need the concentrated food of marine mammal blubber. Juvenile elephant seals, migrating back to the Central Coast, make a good blubber meal.

Ranging from a few hundred pounds to well over a thousand, juvenile elephant seals are also easier prey than mature elephant seals. Especially bulls, at more than two tons. Sharks are stealth predators, attacking from behind and below. They take a bite, and then withdraw to give their prey time to bleed out and die.

If the bite isn’t fatal, the seal escapes, with a scar to tell the story.

This seal survived a terrible wound.

After feeding well on elephant seals in the fall, white sharks migrate out to the Shark Cafe. Sharks take a month to reach it, halfway between Hawaii and Baja California.

Officially called the Shared Offshore Foraging Area (SOFA) the White Shark Café it’s the only place so far identified where adult and sub-adult White Sharks from Mexico and California, males and females, intermingle.

Back in California, elephant seals with sharkbite scars are common on the beach. The Ones That Got Away.

 

Marine Mammal Center tests HPAI vaccine

Cow vaccine could help protect rare Hawaiian monk seal

The Marine Mammal Center is testing Highly Pathogenic Avian Influenza vaccine on elephant seals at its Sausalito hospital. If it is effective in producing antibodies, TMMC plans to vaccinate Hawaiian monk seals. TMMC’s Ke Kai Ola monk seal hospital is on the island of Hawaii.

Hawaiian monk seals are classified as Endangered, with only 1,600 seals surviving. They are “one of the rarest seal species in the world, and conservation efforts are critical to their survival,” according to the TMMC website.

HPAI infects birds and mammals

HPAI, caused by the H5N1 virus, is highly contagious and deadly to several species. It has now infected species from wild birds to domesticated birds and even to mammals. That species-to-species transmission makes a threat to global biodiversity.

Monk seals may be vulnerable to HPAI, as may the Central Coast’s herd of Northern Elephant Seals. In 2023, HPAI wiped out Southern Elephant Seals in Argentina, killing more than 96 percent of the pups, 17,500, born there, and an undetermined number of adult seals. Scientists studying the colony say it may take 100 years for the colony to recover to the numbers it had in 2022, 18,000. 

Elephant seals try the vaccine

Veterinarians advised testing the vaccine on elephant seals first, to avoid risk to the already precarious status of monk seals. National Oceanic and Atmospheric Administration officials, which have jurisdiction over National Marine Sanctuaries, also consulted on the trial.

“Northern elephant seal research has taken tremendous steps forward over the past decade within our shared network of west coast research partners,” says Dr. Sophie Whoriskey, Associate Director, Hawai’i Conservation Medicine at The Marine Mammal Center. “This vaccine trial on six in-care elephant seal pups at our Sausalito based hospital is especially significant given the great risk that Avian Influenza actively poses for marine mammals.”

The Marine Mammal Center’s Dr. Dane Whitaker (left), Associate Veterinarian, and Sarah Pattison (right), Director of Hospital Operations, collect a blood sample from a northern elephant seal patient during an Avian Influenza vaccine trial at the Center’s Sausalito, California, based hospital on July 14, 2025. Photo by Bill Hunnewell © The Marine Mammal Center

The six young elephant seals who were in the vaccine trial had been rescued and were already at the hospital for treatment. The vaccine is one that was reformulated by Zoetis, a veterinary pharmaceutical company, from the HPAI poultry vaccine for use on cows. HPAI in California dairy herds has caused milk production to decline more than 10 percent, and caused other costly herd problems. HPAI has been found in poultry flocks and dairy herds in other states and countries.  

HPAI has also affected egg production across the country. The only strategy for controlling HPAI in poultry flocks is to depopulate, kill, all the birds in the infected flock. The reduced production of eggs and milk has had uneven effectson consumer prices. 

Vaccinated and Placebo groups

The vaccine trial started in July, when three of the seals got the vaccine, and three got a placebo. Some briefly developed hives, including one who got the placebo, but the hives lasted only a few hours. One of the seals in the placebo group died. That seal’s death is under investigation. The seals were already at risk, hospitalized for other reasons.

All else proceeded well, with no other symptoms in either group. In late August, the researchers collected blood samples from the five seals, who had all recovered from the problems that caused them to strand and be treated at the hospital.

Healthy and able to survive in their wild home, they were released to resume their elephant seal lives.

Veterinary experts at The Marine Mammal Center’s hospital and visitor center in Sausalito, California, carefully place a post-release tracking tag on the head of a northern elephant seal pup as part of an Avian Influenza vaccine trial on August 27, 2025. Photo by Bill Hunnewell © The Marine Mammal Center

The blood samples they left behind will be evaluated for HPAI antibodies. With those results in hand, the TMMC team will decide whether vaccinating wild monk seals is worthwhile.

“These individual elephant seal patients are providing valuable information to inform any future vaccination efforts to a related species, Hawaiian monk seals, that are endangered and at heightened risk due to their current population size,” Dr. Whoriskey said. “This initial pilot study has showed us encouraging signs that this vaccine is safe and we are in the early stages of measuring the antibody response produced to determine whether it is also effective. As more information is gathered post-release on these seals, consultation and discussions with study partners will be key in finalizing any future vaccination plans.”

If they decide to vaccinate the monk seals, the veterinarian will use a pole syringe to inject seals on the beach, to keep distance between the veterinarian and the seal.

“We may decide to go forward even if we’re not seeing a very strong antibody response,” said Dr. Whoriskey, noting that the seals did not have any pre-existing immunity to the virus. “Something is probably better than nothing in this case.”

Immunizing wildlife

Vaccinating wildlife sounds impossible, but Ventana Wildlife Society has done it for the Central Coast condor flock. The research team captures every condor at least once a year, to check for lead poisoning, so they have the birds in hand to vaccinate.

Andrea Goodnight, DVM, came to Big Sur to vaccinate condors against HPAI. Phoo credit Ventana Widlife Society. 

Ninety-eight condors of the Central Coast flock, 89 percent, have received at least one dose of the HPAI vaccine, and 72 of those 98 have received the second, booster, shot, and are fully vaccinated. 

In Arizona in 2023, an HPAI outbreak affected 25 California condors, killing 21 of them. California condors are also classified as Endangered.

The main threat to condor survival as a species is lead poisoning from consuming lead ammunition in carcasses shot by hunters. HPAI is another threat to the condor species’ tentative recovery from near-extinction in the 1980s.

California condor. Photo credit Tim Huntington

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.