(Phoca leonina)
Photo by Jo Anne Basinger
Which mammal is most closely related to the elephant seal?
An elephant? A bear? An otter? A wolverine?
Why winter?
It’s baby season!!!!!!!!!! Who doesn’t love babies? It’s also an incredible opportunity to watch the intricate social structure of elephant seal life.
Weathering the storm
Elephant seals are used to storms. They’ve evolved with them. They may have suffered some minimal losses due to this season’s storm surge, but not as badly as you might think. Those storms came at the beginning of the season, and there weren’t many females and babies on the shore. Those that were there had space to move up and most did. Last year ~2,000 pups were born at Piedras Blancas, this year they expect a similar number.
Family Life
Harem- 10-60 females (usually the larger the male the larger the harem)
Female elephant seals spend almost all of their adult life pregnant or nursing. They experience an 11 month gestation period followed by 28 days of nursing.
At birth, mother and baby bond. They communicate with one another and sniff each other so that they know each other’s voice and smell.
While they are on the beach during the birthing season, a mother elephant seal will lose about a third of their body weight due to giving birth, nursing her baby (50% milkfat) and evading males.
Pups are about 300 lbs when they head out to sea. When mom leaves, pups are on their own! Young elephant seals are prey for other ocean life like sharks and orcas.
Only about half make it through their first year of life!
Superweaners
Superweaners are babies who have learned they can nurse from more than one mom! These pups can be more than 600 lbs when they head out to sea!
Sexually dimorphic–
Males can be up to 3 times the size of females. (Females at about 2,000 lbs and males around 6,000.) Males sport a giant proboscis that aids in creating the sexiest vocalizations known to female elephant seal kind. The proboscis is specially designed to reabsorb moisture- so he can toot all he wants and not dehydrate even though he’s not eating during the time he’s beached.
Most of the births are in January and most of the mating is in February. Nov-Feb, males battle for dominance on the beach while females are giving birth. During this time you can hear them vocalize and chest bump. It is mostly display, but it can be bloody.
Numbers
There are roughly 150,000- 200,000 northern elephant seals at this time. Although each year scientists are discovering new haul out spots and they are anticipating a growth in population.
They are considered to be a species of Least Concern right now.
Travels and Adaptations
Elephant seals spend months out at sea. Twice a year, the males go north and the females go west..Males swim up to 10,000 miles per year! They can stay underwater for almost 2 hours!
A typical dive is 20-30 minutes.
From the Friends of the Elephant Seal, on diving: “When diving to hunt, the northern elephant seal first exhales, emptying its lungs of almost all air. This reduces buoyancy and protects the seal from the bends (decompression sickness). All of the oxygen used to provide the energy needed during the remainder of the dive is stored in the red blood cells and the muscles. At the beginning of the dive the seal swims with its tail fins, however during the rest of the descent, almost 90% of the time the seal simply glides.”
“To enable the long period without breathing and the rapid recharge at the surface, the northern elephant seal has a very different surface and underwater metabolism. At the surface the seals have a heart rate of between 80 and 110 beats per minute. When diving, the heart rate drops typically to one-third the surface rate and occasionally as low as 3 beats per minute. Circulation becomes limited almost completely to the heart and the brain so that oxygen consumption is minimized.”
Elephant seals have blubber- this helps keep them warm and also reduces drag while swimming or gliding.
Annual Cycle and Molting
Twice a year, they haul out onto the shore: birthing season and molting season. While they are onshore, they are generally not eating. Most of the births are in January and most of the mating is in February.
Nov-Feb, males battle for dominance on the beach while females are giving birth. During this time you can hear them vocalize and chest bump. It is mostly display, but it can be bloody.
Future
Ocean pollution (entanglement), acidification, climate change and all things that affect the ocean also affect these magnificent beings. Minimize waste when possible, recycle and keep trash in the trash can.
What can you do?
Car discussion: what can you do to help elephant seals from where you are in Los Angeles?
Terms To Know
Marine Mammal– Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears.
Molting– Elephant seals molt each year between April and August, shedding not only their hair but also the top layer of their skin. This is known as a catastrophic molt. They return to rookery beaches for a few weeks while molting. Females molt in the spring, juveniles in the early summer and males in the late summer.
Rookery Beach– A beach where large numbers of rooks or certain seabirds or marine animals, such as penguins or seals, nest or breed.
Species of Least Concern– A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of species conservation because the specific species is still plentiful in the wild.
Vibrissae– helps an animal locate prey and navigate their environment. Vibrissae are connected to blood vessels, nerves, and muscles. They are an important sensing tool.
Pinniped- “ fin-footed” Pinnipeds are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae, Otariidae, and Phocidae
The answer to the question at the top is “bears”! They share a relatively recent common ancestor.