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.

 

TMMC team rescues entangled elephant seal

Cutting the packing strap off freed the seal 

At 8 am the morning of May 8, with the sun lighting the sky but not yet over the hills, a team of marine mammal rescuers climbed down on to the beach among the Piedras Blancas elephant seals. Within the hour, the seal, a plastic packing strap tight around its neck, was freed from his entanglement.

He turned to argue with a neighboring seal, and they sparred.

“Our entangled seal – we called him Rabble -- ended up squabbling with another male as we left the beach,” said team leader Aliah Meza, operations manager of The Marine Mammal Center’s San Luis Obispo Operations site in Morro Bay.

Rabble couldn't resist starting a fight. Photo by Laurie Miller © The Marine Mammal Center, NOAA permit #24359

Docents see him on the beach

The entangled seal was first reported by Friends of the Elephant Seal docents on April 27. The seal was on the north beach at the Piedras Blancas elephant seal viewpoint, crowded among other seals.

Docents saw him and reported the problem. (Christine Heinrichs photo)

“These situations are life-threatening to the animals,” she said. “If we did not intervene, that animal would not survive.”

As soon as she had reports and photos of the seal, Meza began planning how to rescue it. Photos help her determine what the seal is entangled in, the size and condition of the seal, what’s on the surrounding beach.

"We have experience from the last few years of going on to beaches with active rookeries,” she said. “We felt pretty prepared.”

The plastic packing strap is a common entanglement. Meza has removed packing straps from other seals, using a clipper.  This one looked especially tight, though. Difficult to get a clipper between the skin and the strap.

“We have a lot of natural history with the Piedras Blancas rookery,” she said. “We knew he was going to be on the beach for a while, molting.”

Planning to get among the seals

The beach is crowded with seals in May, more than even during the breeding season. Around 5,000 adult females are in the rookery, which extends from north of the Piedras Blancas light station to about a mile south of the viewpoint. Thousands of juvenile seals, both males and females are also on the beach at this time.

They are there to molt, the skin peeling off in pieces. The seals need to be out of the water, on the sand, to allow their new skin to emerge. Visitors can handle pieces of skin from FES docents, identified by their blue jackets, at the viewpoint.

Meza decided that it would be best to sedate him, to give the team the best chance of success. Associate Veterinarian Heather Harris would inject the seal with sedative to immobilize him.

Rabble resists the efforts of the team to corral him. Photo by Laurie Miller © The Marine Mammal Center, NOAA permit #24359

Dr. Harris and Meza estimated the seal’s weight from the photos, to determine the proper drug dosage: enough to settle him, without drugging him too long. Every rescue is a balancing act between too little and too much.

This seal weighed about 190-200 kg, 420-440 lbs. Sedating him also meant they would have to bring a team to prevent him from escaping to the ocean before the drug took effect.

With the seal sedated, they could cut the strap off and then examine the wound, to see how deep it was, and whether it needed further treatment.

Finding one seal among thousands

As she made those plans in April, the seal slipped away. Docents searched for him, but no sign. Until Friday, May 2. There he was, this time on the south beach. He was still there on Wednesday, May 7, shifting around, moving toward the cool edge of the water on a warm day.

Meza got the plan ready and assembled the team of staff and volunteers to go on Thursday morning.

She had cleared it with National Oceanic and Atmospheric Administration, which has jurisdiction over the beach, within the Monterey Bay National Marine Sanctuary. She notified State Parks, which handles the viewpoint and the docent program.

“If we’re going to go down on the beach and disturb other seals to help one with a life-threatening injury, we want to have the highest chance of success,” she said.

The team goes into action

The team left the Morro Bay site at 6 am, and arrived at the viewpoint by 7. By 8, they were climbing down onto the beach.

“Being on the south beach worked in our favor,” she said. “There’s more beach there, to give us more space between us and the animals on the beach.”

Early morning means fewer visitors and less potential for disruption. The team included safety officers and communications people to take photos and video, write notes, and speak to the public.

“We have someone to communicate what’s going on,” she said. “It’s a public viewing area.”

Four team members with boards stood between the seal and the water, to prevent the seal from escaping. Others with boards pressed the seals around the target seal to move away. They complained, but weren’t aggressive. During this part of their year, they have no reason to be.

“There was no risk to mom-pup pairs, and no dominant adult males on beach,” she said. “Generally, they didn’t mind us.”

Sedating the seal

With the target seal isolated from the others, Meza and Dr. Harris had space to inject the seal. They used a pole syringe, to keep some distance from the seal, who had raised up and was waving his head around and vocalizing.

The syringe worked on the first try. He was soon overcome by the drug, and they could go to work.

First, they cut the strap off. It wasn’t as tight as it was two weeks before. The seal had lost some weight. Seals don’t eat while they are on the beach. Molting seals lose about a quarter of their weight during the four weeks or so they are on the beach molting.

In Rabble’s case, that 2 cm, less than an inch, made removing the packing strap easier.

The strap hadn’t yet cut into any vital organs. The cut was superficial, through the skin and into blubber, but will heal on its own. Rabble will have the scar forever, though.

They took blood and rectal samples, and gave him two orange flipper tags. Pups born on Piedras Blancas get white flipper tags, but seals that are rehabbed get orange tags.

Tracking Rabble

Docents will continue to watch for Rabble and his two orange tags. He was at the beginning of his molt, so will be on the beach for several more weeks. Those tags will identify him in the future as well.

“It will be great to track this animal,” Meza said. “Unfortunately, these packing straps are common entanglements. While I was on the beach, I saw another seal with a scar. We might see that one again and be able to identify it.”

After The Tribune published the story of Necklace, who was also entangled in a packing strap, in May 2024, a Cambria restaurant owner approached me and said that he gets a lot of supplies with packing straps, and that he would never again throw one away without cutting it.   

“The impact of plastic and ocean trash on these animals is severe,” Meza said. “That’s why NOAA gives us permission for these special responses. We can all make an impact. The more we know, the more we can do to help.”

Christine Heinrichs is SLO At Large Member of the Monterey Bay National Marine Sanctuary Advisory Council. Her elephant seal column won first place from the National Society of Newspaper Columnists in 2024. Learn more at her elephant seal Substack at (5) Elephant Seals | Christine Heinrichs | Substack

Spring Break for Seals!

Resting seals molt their skin

The spring months bring more seals to Piedras Blancas than even the winter breeding season. All 5,000 or so adult females return, along with five thousand or so non-breeding juveniles. It’s the busiest beach season for these migratory seals.

The seals look ragged, like something is wrong with them. Their skin is peeling off.  For northern elephant seals, it’s normal, the annual molt. They will be on the beach through June.

Raggedy old brown skin peels off.

Berney LeBoeuf, in his book Elephant Seals: Pushing the Limits on Land and at Sea, recounts an incident from the 1960s, when elephant seals were unfamiliar to local residents. A woman called police to investigate the scruffy-looking seal on the beach near her house. The policeman who responded agreed that the seal was suffering, and shot it to relieve its misery. “Of course, the seal was fine,” he writes, “it was just molting, as residents came to learn with the increasing influx of seals in the following years.”

Molting

Elephant seals, like only one other seal (the Hawaiian monk seal), molt their skin annually in a few weeks. All other seals molt, but gradually, one hair at a time, like dogs, so it isn’t as noticeable.

Elephant seals form a new skin layer under the old skin. Blood stops supplying the old skin. It dies and peels off in pieces. Scraps of it skitter across the beach. Friends of the Elephant Seal docents have samples of it to show visitors. Children enjoy handling it. Adults are more dubious, extending a cautious finger for a touch.

The seals stop eating when they are on the beach at the rookery, fasting for that four weeks it takes for them to complete their molt. Female seals lose about a quarter of their body weight while they lie on the beach and let their skin 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.

Silvery gray among last year's brown skin and fur.

The skin begins to molt off around eyes and ears, old scars, and other body orifices. Then the belly and sides and back peel off.

Old scars remain, but temporary marks peel off with the skin. That’s one of the challenges of identifying seals for research study. Numbers bleached or dyed on the fur peel off when the skin molts. Resighting seals with dyed numbers before their skin peels off rarely happens. It depends on the luck of the seal being at a place and time when someone sees the mark and reports it.

If you see a marked seal, report it to a docent or contact elephantseal.org.

Seals can also be identified with small plastic flipper tags, but those numbers are difficult to read from a distance.

Pup embryo development

Unseen, next year’s pups are starting to develop. The females mated after they weaned their pups in February and March. That fertilized egg entered a state of embryonic diapause, or delayed implantation. Development was suspended, allowing the mother to regain blubber and condition after the weight loss of nursing her pup. Embryonic diapause times all births to happen around the same time.

These slightly pregnant females spent the next ten weeks feeding freely. Now, in April and May, their bodies prepare for the embryo to begin gestation.

Embryonic diapause happens in other mammals. In some, it’s a response to conditions. In elephant seals, all pregnancies start this way.

Juveniles

Juveniles, male and female seals not yet ready to breed, have been foraging and growing at sea while the adults dominated the beach during the winter breeding season. The beach, although crowded, is calmer now. No bulls fighting for dominance.

Seals of various sizes and ages molt together, except for the largest bulls, which are migrating. 

Bulls are on their northern migration. They will return to the beach in July and August, time for them to molt their skin.

Mercury bioaccumulation

 

The molted skin takes with it some of the mercury that the seals have accumulated from the mercury in the ocean. The mercury got there from coal-burning plants, discharged into the atmosphere and rained down on the oceans. Top predators such as elephant seals bioaccumulate it as it goes up the food chain.

 

Shed skin and other excretions from the elephant seals at Ano Nuevo are a major source of methylmercury contamination there, influencing the bottom of the food web.

 

Methyl mercury is a human neurotoxin. Mercury affects the seals’ hormone levels, immune system and the ability to reproduce successfully, which may affect the population. Research continues on how mercury may be affecting the seals.

 

Their peaceful spring rest on the beach belies the drama of their lives, within their pregnant bodies, and in the effects of human activities on their habitat.

 

 

Ellie Season for Rescuers

Stranded pups wash up on area beaches 

The pups born this season at Piedras Blancas have been weaned. They’ve developed skills to survive, and many have left the beach on their first migration. Some can’t quite make it in the ocean. They wash up on local beaches, underweight and exhausted.

“They are coming in at 30 to 40 kg (65-90 lbs), below their birth weight,” said Shayla Zink, operations manager for The Marine Mammal Center’s Morro Bay facility.

Stranded weaners may still have their black birth fur, or they may have molted that to their Silver Bullet skin, brown on their backs and silver on their bellies.

 

Three of these weaners are fat, but the one in the middle is thin. This one also hasn't fully shed its black natal coat, still peeling off. 

Growing up Weaner

Weaned pups stay on the beach for six to eight weeks after their mothers leave them. Successful pups have gained enough weight to keep warm in a comfortable coat of blubber. That blubber also supports them during the time they remain on the beach, when they have finished nursing but aren’t yet hunting and eating fish.

They also grow a second set of teeth, molt their baby fur, and develop their oxygen capacity. They practice swimming and holding their breath, so that they will be able to dive and hunt for prey out in the ocean.

Most of the pups get that far, but some don’t. They are the ones lying on local public beaches, among driftwood and rocks that camouflage them, or unprotected on the sand. Most frequent locations for stranded weaners include Morro Bay, Avila Beach, Oceano, Pismo Beach, and San Simeon Cove.

What to do?

It’s never advisable to approach a stranded seal on the beach. You or your dog could catch something, or get bitten. From the seal’s perspective, humans, even well intentioned, are threatening. Stranded weaners are especially vulnerable.

“They are so malnourished and dehydrated that they are very lethargic on beach,” said Giancarlo Rulli, associate director of TMMC public relations. “It’s easy for an off-leash dog or someone concerned to get within a few feet of them, to poke it with a stick to see if it’s alive.”

Finding a weak pup on the beach can be a highlight of a Central Coast visit. Visitors want to do the right thing, but don’t know what to do. Shooing an exhausted pup back into the ocean adds stress to its already weakened condition. It can scare the pup, making the rescue team’s job more difficult.

“Any extra energy they have to use defending themselves from dogs or people detracts from their ability to develop the skills they need to survive in the ocean,” Zink said.

Call for help, The Marine Mammal Center 24-hour hotline, 415-289-7325 (SEAL). Take photos. Find out what the location is. Find beach staff members of other agencies and ask for advice.

“It’s Spring Break. People are heading to the beaches,” said Zink. “Whoever you report it to, State Parks or Friends of the Elephant Seal, they will report it to us.”  

TMMC will send out a team to evaluate the animal and rescue it if necessary. It may just be resting on the beach, not in need of any intervention. Or it may have other injuries that need attention. The goal is to return all marine mammals to their ocean home, strong enough to survive there.

The Marine Mammal Center’s hospital in Sausalito is currently dominated by elephant seal pup patients.

Getting the word out

Finding a stranded seal isn’t something that beachgoers are prepared for. Rulli wants to change that, so that they’ll have the tools they need to report a stranded marine mammal “in their back pocket, on their beach checklist like a towel or sunscreen.”

He’s spreading the word to watersport businesses such as kayak and surf shops and nonprofit organizations engaged with the coast. Restaurants and hotels are other possible locations to support public education on dealing with marine mammals on the beaches, here along the Blue Serengeti.

“It’s a message of hope,” Rulli said, “keeping marine mammals safe.” 

TMMC rescued more than 400 marine mammals in SLO County in 2024.

Successful weaners

 

This pile of elephant seal weaners includes some that still have their birth blackcoats and some that have molted to Silver Bullets.

Even for the strong, healthy weaners, it’s a tough ocean. Only half will survive that first migration. Those that do will return in the fall, then officially considered Young of the Year.

Follow satellite tagged pups at Team Ellie, Cal Poly’s elephant seal research team, led by Associate Professor of Biological Sciences Heather Liwanag.

TMMC Needs a New Site

After 20 years at the Morro Bay site, behind the power plant, TMMC needs to find a new location for its SLO operations. Vistra Corp has other plans for the site. TMMC is asking the public to send any leads on possible commercial properties that could be TMMC’s new SLO County home.

They need enough space for the office and fish kitchen indoors, and outdoors, cages for rescued animals. Storage for various supplies and gear. Convenient access for rescue trucks and vans. Parking for volunteers and staff.

With changing ocean conditions, more marine mammals may need TMMC’s rescue in the future. Currently, warm ocean conditions are fueling a bloom of toxic algae in Southern California, with some sea lions affected by domoic acid toxicity along the Central Coast. During 2024’s DA outbreak, TMMC rescued more than 200 animals within a two-month period.

DA typically affects sea lions rather than elephant seals, due to differences in what they eat. Sea lions feed on the fish that eat the algae and bioaccumulate the toxin.

“We have to change as the ocean is changing,” he said.

TMMC is tapping every agency and real estate broker in the area. If you have an idea, send it directly to the email set up for property suggestions, slo@tmmc.org.

“Our eyes and ears are open,” Rulli said. “We will take any leads.”

Christine Heinrichs is SLO At Large Member of the Monterey Bay National Marine Sanctuary Advisory Council. Her elephant seal column won first place from the National Society of Newspaper Columnists in 2024.

 

 

 

Tribune elephant seal coverage

 The Tribune used AI to compile a list of stories about elephant seals over the past year or so. It's posted here. 

Just Animals on YouTube

 I recorded a YouTube video with Elle and Guy Schwartz. Fun, and another way to tell the world about elephant seals. 

Weaned pups are fat!

 Growing up Elephant Seal

Elephant seal pups are only a month or two old, but they are being weaned, their first big step to independence. They go from birth weight of around 70 pounds to 200 pounds – or more – in that first month.

They are loud! Visitors hear them as soon as they get out of their cars at the Piedras Blancas viewpoint parking lot. Listen for all three distinct calls: the squawking of the pups, the barking of their mothers, and the bellowing of the bulls.

These fat pups are molting their black neonatal coats. They are ready to wean. Their mothers are thin compared to their fat pups. (Chrisine Heinrichs photo)

Weaner pods

Look for them in groups, called pods, on the beach. Weaner pups are easy to recognize. They are fat, even roly-poly. They were born all black, but they shed that black coat in their first molt. Now they are countershaded, light on the belly and dark on the back. Many marine animals have that color pattern, helping camouflage them from their predators.

Weaning is a major transition in elephant seal life. Pups go from gaining weight fast, 200 pounds or more of blubber in a month, to metabolizing that blubber to sustain them for eight to 12 weeks.

No food now

Long fasts, periods of not eating, are a feature of elephant seal life. Their mothers didn’t eat for the month they nursed the pups. Bulls on the beach may not eat for 100 days. This is the pups’ first fast.

As the mothers come to the end of lactation, they are at their thinnest. Their blubber has been metabolized into milk, feeding those chubby weaners. Neither they nor the bulls have had anything to eat since they arrived on the beach.

Females come into estrus as they wean their pups. They are then ready to mate with the bulls. That’s when the bulls get competitive. Earlier battles were over territory. Now, they battle over breeding. 

Look for bulls raising their heads to stare at each other. One or the other will make a move, and one may back off from a fight. It’s called dominance interaction, displacement. From the viewing area, visitors can see which bull is dominant. 

If neither backs down, they’ll battle. The loser may leave the beach entirely, finding another beach to recover. Deaths are rare. Both live to fight, and breed, another day.

Weaners stay out of the way of the adults, who are still in the drama of breeding. Mid-February is the height of the breeding season, but it will continue through March. X-rated.

Swim School

It’s not all sleeping in the sun. Weaners have developmental tasks to accomplish to prepare for their first migration.

Some of that blubber will become muscle as they tussle around the beach. They lose their baby teeth and get their permanent teeth, so they can hunt their own food. The better to eat fish with!

Pups aren’t born with much ability to swim, so this transition time is when they go from beach to ocean. They venture into the surf to practice diving, swimming and holding their breath. Weaned pups learn to hold their breath for around six minutes, some as long as 12 minutes. That will help them stay underwater and dive deep enough to catch food. They are on their own now.

Weaners may be splashing around during the day when visitors see them, but they do most of their practicing at night. Most will leave the beach on their first migration by the end of April.

Watch a video on the Friends of the Elephant Seals YouTube channel.

How to weigh a weaner

Cal Poly’s Team Ellie, led by Associate Professor of Biological Sciences Heather Liwanag, has been weighing weaners at this stage of their lives since 2018.

It takes a team to weigh a weaner! Team Ellie has the equipment and training to get it done, and collect data to understand the elephant seals. (Kenzie Davidson photo under NMFS permit 27514-01)

They mark potential pups to weigh when the pups are about two weeks old. They mark the pups with a letter-number code, using hair dye.

Pups are still nursing at that point. They stay with their mothers until the mother weans them. Weaning is abrupt: the mother simply leaves the pup on the beach, mates with one or more bulls, and swims back into the ocean.

The team keeps track of the now-weaned pups by the dye-marks. As team members re-sight them after they are weaned, and no longer with their mothers, Team Ellie takes their equipment down to the beach to weigh them.

Weaners are generally mild-mannered, but they are wild animals. Dr. Liwanag and Team Ellie members, who have trained to work with these animals, corral them into a canvas bag they had specially designed to be the right size and shape for weaner weighing. It’s snug enough to safely keep their front flippers next to the body and let the back flippers hang out. Except for a hole to breathe through, the weaner’s head is inside the bag. Keeping the eyes covered helps keep the pup calm for the five to ten minutes while it’s being handled. The pup can’t poke its head out.  

“That's where the bitey bits are!” Dr. Liwanag said. A 300-pound weaner can give a nasty bite.

Once contained, the whole weaner, bag and all, is hooked to an industrial scale suspended beneath a 10-foot tripod. Each seal gets two white flipper tags, one in each rear flipper. White tags designate the Piedras Blancas rookery, and double tags indicate that this seal was weighed. Team members measure how long the seal is, and how fat it is, around the underarm girth. These procedures were approved under NMFS permits 22187 and 27514, a California State Parks Scientific Collections Permit, and by the Institutional Animal Care and Use Committee at Cal Poly.

The weaner on the left has its first countershaded coat. The one on the right is molting its black newborn coat. (Kate Riordan photo under NMFS permit 27514-01)

Weaners typically weigh between 220-330 lbs.

Data analysis can increase understanding of how weaner weights relate to overall population trends at Piedras Blancas.

“The population has been fluctuating at the Piedras Blancas colony in recent years,” Dr. Liwanag said. “Comparing weaner weights between years will give us further insight into the health of the population, which may be approaching its maximum population size at this breeding site.”

The Bill & Linda Frost Summer Undergraduate Research Fellowship will support an undergraduate student next summer to work on the data.

Weaners or Weanlings?

Weaned pups may be called either weaners or weanlings. Weaners is an earlier name, perhaps sounds more comic. Weanling is more formal, sounds more scientific. Weaner seems to me to fit these seals, at a roly-poly stage of life.

“I would definitely still call it weaner weighing!” said Dr. Liwanag.

Docent training

If you love those seals, you could be a docent. Hearst San Simeon State Park is recruiting volunteer docents for spring training. Docents become informal educators and wildlife interpreters to visitors to the viewpoint.

The application deadline is March 2. Apply here Meet the State Parks interpreters who lead the program at in person interviews in San Simeon during the first two weeks of March.

The training is professional, and includes reference materials and mentoring. Training includes independent study assignments, two virtual sessions and two in-person sessions. After training, docents are mentored individually three times on site at the bluff.

The time commitment for docents is three or four, three-hour shifts a month. Docents are asked to commit to at least one year of service. Most stay for years. I’ve been doing it since 2007.

Further information here. Call State Park Interpreter Monica Rutherford at (805) 460-8762 with questions.