Wednesday, March 14, 2018

Juanita's First Day


Starving elephant seal weaners have to learn to catch and eat fish before they can be released into the ocean. The Marine Mammal Center has Fish School, to teach them. Elephant seal weaners may not take to it right away. Here's Juanita, on her first day of Fish School.

https://www.youtube.com/watch?v=Fvo-poD2uz4

Friday, March 2, 2018

Breeding season winds down



The crowds of seals have thinned, leaving pods of weaners gathering along the bluff edges. Some mothers remain, still nursing their pups. Beachmaster bulls keep an eye on those last few, ready to mate one more time.

Typical weaners have nursed their way from their birth weight of about 70 pounds to around 300. They vary – it’s easy to see the difference. Some are much bigger than others. Most are plump and filled out. They don’t have to be fat to survive.

The really big ones are superweaners, They’ve been able to steal milk from other mothers and gain a couple hundred pounds more, achieving superweaner status. Some are so fat, they can hardly move. Being a fatter weaner isn’t a plus. The additional blubber may make it more difficult for them to dive to hunt fish and squid.

Docents sometimes call them Pop Tarts for sharks. Pups make such attractive food for sharks that the increase in elephant seal pups may be responsible for the increase in shark attacks on otters. Sharks may mistake the otters for seal pups, and take a bite. They don’t eat the otter, but the otter is already dead.

The weaners will all lose some weight before they depart on their first migration in March and April. Their metabolism changes. Nursing pups gain weight as blubber. As fasting weaners, they convert the blubber to muscle and energy. Their blubber will have to support them until they leave the beach and embark on their first migration, when they start finding their own food.

The mothers lose about a third of their body weight nursing their pups. The few remaining on the beech are thin and depleted. The other mothers have already left on their short migration, for two months, after they wean their pups. They will be back in May.

A few adult bulls sleep on the beach, hanging around to mate with the last few females. The males are thin, too. They’ve been on the beach without food for nearly 100 days. They are still big, but lack the bulk they brought with them in December.

Sleeping takes the edge off that long fast.  

The Marine Mammal Center rescued its first starving pup of the season February 20.

The volunteers who collected him from Moonstone Beach named him Kickoff, for kicking off the elephant seal pup season. He was taken to the Morro Bay facility for supportive care before being sent north to the main hospital in Sausalito. They bulk him up with seal food and teach him how to eat fish on his own.

If you see a pup stranded on the beach, call The Marine Mammal Center to report it, on the rescue line, 805-771-8300. Don’t go near it or touch it. They are wild animals and even a starving pup has teeth and can bite. Some carry diseases that humans can catch. Your report is important and you may be asked to help. The person reporting the stranded animal is usually allowed to name it. Helping save one of these unusual animals is rewarding.


Wednesday, February 21, 2018

NOT Ella

The Marine Mammal Center rescued the first elephant seal pup of the season. The MMC volunteers named the pup Kickoff, for kicking off the season.

He (or she, sex not yet determined) is far too thin. He appears to have molted his black natal pelage, so he's had some nursing experience.

Diana Kramer, site manager for the San Luis Obispo facility in Morro Bay, notes that Kickoff shows the “peanut head” (dip between head and shoulders), prominent hip bone area, and loose baggy skin that are typical of starving pups. "This indicated to us Kickoff was significantly underweight and needed rescue," she said. 

These mothers are showing some indications of the loss of blubber in their necks. They are all thin after nursing their pups.
Kickoff will get the supportive care he needs and be released when he is able to manage on his own. 

Monday, February 19, 2018

Beach changes

Ella is one of many weaned seals on the beach now. They are collecting themselves into pods.

Some have not completed their first molt yet. Others have, and look like young seals, like the one on the right.


The few mothers who remain on the beach are thin from nursing their pups.


They will soon join their sisters back in the ocean, feeding and gaining blubber.

Monday, February 5, 2018

Weaners

Ella is one of many weaners on the beach now. I can't tell which one she is. She doesn't have any distinctive markings, so one weaner looks pretty much like the next.
She and the other weaners will stay on the beach for two months or so. Right now, they are resting and playing. They won't have anything to eat until they get out into the water and embark on their first migration. This is their first long fast.
As they sleep on the beach and cavort in the surf, their metabolism is changing. They spend the next eight to ten weeks without food, living off that blubber. Their bodies convert some of it into muscle. They also increase the amount of blood and the oxygen-carrying capacity of their muscles, important adaptations to allow them to dive deep. The black coats they were born with are replaced with lighter tan and silver coats.
Weather continues warm and sunny, no rain in the forecast for the next two weeks. So warm that today, the seals moved close to the water to stay cool. As the tide came in, the pups and their mothers barked and flapped around. They were upset, but the pups that were too close to the water were big enough to get themselves up the beach and out of trouble. I think they were all probably okay.  

Tuesday, January 30, 2018

Visiting the seals

My monthly column about the seals appears in The Cambrian in the last issue of the month:
http://www.sanluisobispo.com/news/local/community/cambrian/cambrian-opinion/article196370769.html

You hear them as soon as you get out of the car. It’s pup time at Piedras Blancas. More than 5,000 pups will be born in the rookery, which extends from beyond the light station in the north to about two miles south of the viewpoint.

Most pups are born at night, but you might be fortunate enough to be watching when one is born on the beach.
Each pup is accompanied by a mother, and mature males hover, awaiting the opportunity to mate. It’s one of the busiest months on the beach, and the most active.
Females are still arriving to give birth. Look for seals that are urgently tossing sand on their backs. It doesn’t have much to do with the process, but seals seem to do it when they are stressed.

Gulls scream and flap around new births, so follow them to the newborn. They consume the afterbirth, part of nature’s recycling. The beach would be disgusting without them cleaning it up.

Once born, the pups need to start nursing. The first pup was born on the south end of the beach Dec. 16, so that pup will be the first one weaned. Look for rotund, fat pups. Some will learn to steal milk from other mothers, ballooning up to even more than the usual 300 pounds. Those 500-pounders are superweaners.

Although mothers and pups bond to each other at birth, barking and sniffing at each other, it’s far from a perfect system. Eighty percent of pups nurse on at least one mother other than their own. Not every pup survives, and those bereaved mothers may adopt one or more strays. Some mothers are particular and chase pups other than their own away, but most are tolerant. Elephant seal mothers have never been observed to give birth to more than one pup at a time.
Nursing more than one pup puts the nursing couple in jeopardy. Mothers don’t eat while they are nursing. They produce the milk from their blubber, losing two pounds for every pound the pup gains. Stray pups are nursing from a limited source.
It appears to even out. Around 95 percent of pups at Piedras Blancas survive to be weaned. Younger mothers may gain experience by nursing more than one pup. Pups of experienced mothers are more likely to survive.
As pups are weaned, mothers come into estrus, heat, like dogs. They mate before they return to the ocean, thin and in need of food. They’ll spend three moths feeding before they return to the beach with some of their blubber reserves restored.

Estrus and mating spark battles between males. Most dominance interactions are simple: a challenge and a retreat. But with breeding rights at stake, males are willing to fight. They bump chests and rip at each other’s chest shield, the crinkled skin around the neck, with their teeth. Battles can be bloody. Dominant males take no notice of pups or mothers as they chase each other across the beach. Pups can be separated from their mothers, a serious problem and the single most common cause of pup death. Pups can even be killed as males land on top of them in their determination to be the most dominant, or to mate with the mother.

Watch as two bulls challenge each other, and their conflict ripples through the rest of the seals. With new females arriving, pups born, pups being weaned, mothers mating and departing, the scene is constantly changing.

Thursday, January 25, 2018

Molting

Ella continues to molt her blackcoat. And, from this photo, appears to be a male.

He's staying close to the edge of the bluff. That keeps him out of the way of mating, which is now frequent among the adult seals. As the pups wean, their mothers go into estrus and become receptive to mating. Females mate with more  than one male before they return to the ocean.
Females typically protest, whether they are in estrus or not.