Friday, March 26, 2010

Sea Lions

The 'unofficial welcoming committee' of the Galapagos Islands is the sea lion. Their playful inquisitive nature, speed, agility on land, and bark quickly make them an island favorite. Sea lions live in large colonies. Adult males known as bulls are the head of the colony. Bulls grow to be up to 7 ft in length and 800 lbs. As males grow larger they fight to win dominance and for a territory including a harem of between 5 and 25 cows. Dominant bulls will fight off any intruders entering the territory.

We were welcomed by sea lions swimming around the boat and 3 or 4 adults taking up residence on our swim platform for the night. They grunted and barked and fought and made whoopee all night long. After viewing the mess and cleaning piles of poop up, we headed off to the ferreteria (hardware store) to see what we could do to discourage all this activity. $14 worth of green plastic netting was procured and installed and (other than being asked if we are now growing tomatoes) it seems to work well…no more sleepovers.

They are still visiting the boat daily and the following video of a baby sea lion swimming with the crew show that they don’t seem too upset that the Emily Grace is no longer accepting boarders.

Each cow in the harem has a single pup born a year after conception. The pups have a strong bond with their mother. The cow will nurture a pup for up to three years. In that time, the cow and the pup will recognize each others bark from the rest of the colony. The mother's will take the young pups with them into the water while nursing. When the pup is 2 - 3 weeks old the cow will mate again.

Within the colony sea lion pups live together in a rookery. Pups can be seen together napping, playing, and feeding. It is common to see one cow 'baby-sitting' a group of pups while the other cows go off to feed.

Sea lions can be seen all over the islands. We routinely see them sleeping on park benches and the local beaches as we walk around the town. Snorkeling with the playful pups has been a highlight of our visit to the Galapagos.

Seals are different from sea lions. They both belong to the scientific order Pinnipedia. The name literally means “fin-footed.” Seals are called earless because they lack the ear flaps that these Galapagos sea lions have. Seals only have tiny openings, which are called pinnae, that serve as ears. Seals hind flippers also angle toward the rear and cannot be rotated forward. This is a hindrance for seals. For a seal to move across dry land, it must balance its weight on to the fore flippers and crawl along using their bellies. Sea lion hind flippers, however, are extremely flexible, and can actually rotate forward and beneath the body. This enables sea lions to move around on land with ease and fairly rapidly when approached quickly. Don’t ask us how we know...


1 comment:

Anonymous said...

Okay - now you've clarified things! In your 3/16 blog you had a picture of a Sea Lion on your transom, but no explanation. Thanks for catching up!
You are observing the extreme cases of adaptation which Darwin explained by "Natural Selection" (some call it "survival of the fittest") which led to his "Theory of Evolution". Oh, yeah, I used to teach biology!
Happy learning -

Uncle Joe