Pinnipeds

Pinnipeds are fin-footed marine mammals such as seals, sea lions, and walruses.  The Alaska SeaLife Center currently is home to harbor seals (Phoca vitulina) and Steller sea lions (Eumetopias jubatus) of the pinniped family. 

Harbor seals are very playful animals and are extremely interactive!  They love to swim around, and will play games with visitors and chase shiny objects (or pencils) through the glass of their tank.

All animals here at the SeaLife Center are given enrichment activities to stimulate themselves.  In captivity, they are not constantly being hunted, or hunting, as would happen in the wild.  Therefore training sessions are held to keep the animals alert and occupied.  For the seals, this includes target training, learning specific commands, creative food puzzles (like freezing fish in a block of ice, or placing it in a milk crate), and even painting!  I was able to observe a training session, and here is some of what I saw.

Roll over!

Touch

Touch my foot!  (I was a little slow with the camera...)

Bark

Steller sea lions are the largest animals we have at the SeaLife Center.  They exhibit extreme sexual dimorphism, with females ranging from 500-800 lbs, and males reaching up to 2000 or more lbs.  The lifecycle of Steller sea lions is very unique, and a breeding research program is being conducted to learn more about the animals and how they reproduce, specifically looking at maternal energy investment in the birthing and rearing of the pups. 

Males typically gather at the “rookery” in early May.  Here they fight with each other to establish distinct breeding territories.  When the females come later in the month, each male will be ready to mate with and protect his harem of females.  The male will remain in his territory for the entirety of the breeding season, and will not leave to swim or feed.  Therefore the males put on considerable weight in the months beforehand, to prepare for 4-6 weeks without food.  Woody, the dominant breeding male at the Alaska SeaLife Center, weighed 2391.4 lbs at the beginning of the breeding season!  He is over 10 ft. tall, and is best described as “HUGE!!”  He has since lost more than 500 lbs in the matter of a few short weeks as the breeding season progressed.

The females come to the rookery in late May or early June when they are ready to give birth to their pups.  They want to choose a place that is close to the water, so that they can feed, but far enough away so that the pup doesn’t accidentally fall in.  Unlike harbor seal pups, sea lion pups aren’t born knowing how to swim!  Many pups are lost each year due to high surf that swept them off to sea.  The males in this zone of the rookery generally have the most success.  Once the female has chosen her spot (and her male) she will give birth to her pup and begin nursing.  About 8 days after giving birth, the female will enter into estrous and mate with the male.  For the rest of the year, she is then nursing a pup while attempting to carry a full term pregnancy.  This is the area of study for the breeding program at the SeaLife Center.  Just how much energy does this take?  And how does the female maintain that necessary supply of energy?

Marine mammals are fascinating creatures!  Here are some fun facts.

1) Marine mammals lose heat to water 25 times faster than to air.  That is why sea otters hold their flippers out of the water, to preserve heat and energy!

2) Sea otters have fur is so thick that it can actually hold air while under water.  These animals are constantly grooming themselves the keep their hair clean and insulating.

3) The Latin name for walrus is “Odobenus rosmarus” which literally means “toothed-walking sea horse”

4) Walruses can constrict the muscles surrounding their blood vessels in their skin to conserve heat, making them turn white.

5) Male hooded seals have a balloon like sac on their nose that they can inflate (I highly recommend looking up a picture of one).  Most of these seals are right nostril blowers, while some employ the left nostril.