Wednesday, February 3, 2016

Pups at high tide


Plenty of pups squirm on the beach in January, under the watchful eyes of their mothers. The bulls are less concerned, with their attention focused on mating. This year’s high tides and storms have added to the chaos.
Elephant seal pups can’t swim when they are born. That inability must be a holdover from their evolutionary past, when their ancestors were land mammals. As helpless pups, they are at risk of drowning as waves inundate the beach.

At Piedras Blancas this year, there’s almost no beach above high tide line at the north end of the boardwalk. Seals have crowded up next to the fence to stay above the water. Visitors are thrilled to get such a close look. But bulls battling each other and mothers shoving each other for space can separate mothers and pups, and make it difficult for them to reconnect. One docent counted 21 pups in a group that included only 14 possible mothers last week.
In the limited space left to mothers and pups, they crowded together to stay out of the waves. Look for mothers surrounded by three or four pups. Elephant seals give birth only to a single pup. Twins are unknown. Mothers don’t eat for that month while they are nursing the pup. They create milk by metabolizing their blubber. Each seal is plump enough to feed one pup, but not more. Any extra drains her resources further. 

Losing track of each other is serious, the single most common cause of pup death. Some mothers will nurse other pups, but other chase them away. Inexperienced mothers may learn from mothering other pups, but the milk they drink may deprive her own pup of the food he needs to grow. Some mothers are willing to foster a pup for a few days. Mothers whose pups die may adopt a stray, or even attempt to steal a pup from another mother.

Last week, one mother searched for her pup as the tide receded. Mothers and pups identify each other by sound and scent. She sniffed around, and barked occasionally. Pups around her slept on, but she likely reconnected with her little one before the tide returned. About 95 percent of the pups at Piedras Blancas survive to weaning.

The south end of the beach has more dry land for pups, so there’s less confusion there. Watch for the dominant bulls, beachmasters, to defend their harems. That big seal with a long nose may appear to be asleep, but he knows is some younger interloper tries to approach a female. He’ll warn the intruder off with a look and a bellow. If that’s doesn’t work, he’ll rise up and wave his nose. He’ll charge and attack the younger bull, who may escape or turn to fight.

Read the column in The Cambrian.

Tuesday, December 15, 2015

Pup season

Two more pups had been born as of December 14. The tides are very high, putting them in danger. Even higher 'king' tides are forecast for December 21, 22 and 23 next week. It's good that the pup season is only beginning and the beach is not yet too crowded.
Fortunately, this mother was staying on the ocean side of her pup. This is the first pup born. He's already very fat, so in less danger than a newborn.
There are three pups in this group, with several other mothers-to-be awaiting birth. This group is on the south section, about halfway out on the boardwalk. The senior male is a calm influence. No less dominant males dared to harass the mothers under his protection.

Tuesday, December 8, 2015

Seals eat hagfish


From this month's column in The Cambrian:


Elephant seals hunt at 1,000 feet and deeper. Digital tracking devices make it possible for us to know this, but much of their feeding behavior remains unknown. It’s too dark down that far for a critter cam to function. One seal was tracked over 17 hours of her day. Most of her dives were 20 to 30 minutes long, down to between 1,500 and 2,500 feet. One dive of over an hour brought her to around 4,000 feet.

Knowing where they go lets us infer that they are eating the fish and squid that live there. One remarkable video did catch a female elephant seal eating a hagfish. It was part of a study by Ocean Networks Canada, which placed a pod at about 3,000 feet deep. The lights and camera went on to record video for 15 minutes in every two-hour period.

It recorded a huge amount of video, so the word went out to citizen scientists worldwide to watch the video and report interesting events recorded. A dedicated 14-year-old boy in the Ukraine watched long enough to see a female elephant seal slurp up a hagfish

Hagfish are living fossils, unchanged over 300 million years. They are primitive fish, with no jaw. Instead, their teeth flex out from inside their lips. They travel in schools, feeding on the ocean bottom, eating worms and carcasses of dead animals that float down.

Eating a hagfish is more difficult than she makes it look. When they are threatened, hagfish nearly instantaneously cover themselves with sticky, gooey slime. [Do the Ghostbusters know about this?] It’s so thick and viscous that sharks have to spit them out. The slime clogs their mouths, making it impossible for them to breathe in water. Elephant seals, even if they took longer to eat a hagfish and it bloomed its slime protection, could eat them anyway. They breathe at the surface, so no problem for them.

Improvements in digital technology will undoubtedly advance so that we can know more about what and how elephant seals eat. For now, we can be confident that those huge seals resting on the beach represent lots of food consumed.

Adult males will arrive in December, preparing for the breeding season to come in January.

Friday, December 4, 2015

First pup!

The first pup of the 2015-16 breeding season was born November 28. Mother and pup are doing fine.

These photos were taken when he/she was two days old. He looks like he's already filling out.

The first birth is usually in late December, but occasionally pups are born earlier. Sometimes they are not healthy and don't survive, but this one is doing fine.

Monday, August 31, 2015

Birdwatching

A good day for birds at the bluff. California gulls as usual, enjoying the company of Heerman's Gulls.
Heerman's Gulls are pretty, with their dark gray plumage and red bills. They migrate up from Mexico at this time of year.
Elegant Terns accompany them. That crest of feathers gives them a jaunty, almost punk look.  

Friday, August 28, 2015

Sleeping giants



 
Summer vacation draws crowds of visitors to Piedras Blancas to see the elephant seals. In August, adult and subadult male seals are on the beach.

Seals are on the beach year round, but as migratory animals with an annual cycle, they are always coming and going. There are fewer seals on the beach in summer than other times of the year.

The seals come and go individually. They don’t live in a group in the ocean, so they make their way back to Piedras Blancas on their own schedules. A large male may lift his head out to announce himself, perhaps inviting a sparring match. Fighting isn’t serious at this time of year, with no females around. Male seals are usually willing to take on a challenger.

These are the biggest, the grand bull seals, weighing as much as two and a half tons. This is a seal worth seeing. Their pendulous trunk-like noses, technically proboscis, give them their name.

They come to the beach to molt their skin at this time of year. Circulation to the hair follicles of the old skin stops, and it simply peels off. Blood flows to the new skin underneath. Research on harbor seals using thermal images show that the new skin gets much warmer as blood flows to it to help it grow.

The seals’ short, stubbly fur looks nearly black when it’s wet. As the sun dries it, it takes on a lighter brown color. Elephant seals weren’t hunted for their fur, the way otters and fur seals were. They were hunted for their blubber, used for lighting oil and machinery lubricant. The invention of electric lighting and lubrication alternatives from petroleum helped save them.

Sea otters, whose fur has as many as a million strands per square inch, rely on their fur for warmth. Those long, waterproof hairs and soft underfur trap air, keeping their skin dry and insulating them against the cold water. Sea otters are creatures of the surface, diving down to the bottom in shallow waters, as far as they can go in one to four minutes. Elephant seals are creatures of the deep. At 1,000 feet and deeper, the pressure would squeeze any trapped air out of their fur. As in so many other ways, elephant seals are adapted to their environment and the niche they occupy.

Males being naturally competitive, they may spar with each other, on the beach or in the water. Mostly, they sleep. Awake or asleep, they may hold their breath for ten or fifteen minutes, apnea. That’s normal for them. As deep divers, they are accustomed to holding their breath. Typical dives are 20 to 30 minutes, but dives of an hour are typical, and dives over two hours long have been reported. When they are on land, each breath expends moisture and energy. Taking fewer breaths, called sleep apnea, is a problem in humans but for elephant seals on land, it conserves energy.

Watch one or two individual seals to see how long they go between breaths. Ask a blue-jacketed docent to show you a sample of shed skin. They are on duty every day.

Tuesday, August 18, 2015

Humpback whales join the seals

John FitzRandolph reports on a young humpback whale in San Simeon Cove:

This story could develop into the North Coast’s marine mammal mystery of the year, and it could prove to be among the most treasured wildlife encounters witnessed here in many years.
For 24 consecutive days (as of Tuesday, Aug. 4), a juvenile humpback whale has been dining on anchovies, sardines and other small bait fish in the San Simeon Cove.

Why has this whale lingered for so many days in the Cove? If there are ample schools of bait fish in the Cove, why aren’t there other whales feeding there as well — as there have been in recent weeks?

Read the rest of his story here.

So this story about humpback whale songs caught my attention: NPR reports:

Read more here: http://www.sanluisobispo.com/2015/08/04/3749066_humpback-san-simeon-cove-juvenile.html?rh=1#storylink=cpy
 
Humpback whales don't just sing songs — they compose with the whales around them, singing a song that evolves over time. Scientists didn't know that until they started recording whale sounds in the 1960s and spent years listening. The evolution of this "culture of listening" among researchers is the focus of Morning Edition's weekly summer series, Close Listening: Decoding Nature Through Sound.
Katy Payne, a researcher in acoustic biology at the Cornell Lab of Ornithology, and her husband, Roger, were the first scientists to realize that the intricate and eerie calls of some humpback whales are actually songs. At a recent visit with Katy in a Cornell sound studio, we played this archived recording of the first whale they ever heard, and she recognized it right away:
"It's the voice of a male humpback whale off shore of Bermuda, in 1964," Katy explained. "It was recorded by a Navy engineer."

Read or listen to the rest of the story here.