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Gregory R. Mann, Ph.D. {ret.}

Galápagos Sea Lion

“Zalophus wollebaeki”

The Galápagos Sea Lion is very large pinniped, with the males averaging about 900 pounds when they are full grown. The females average about 244 pounds at maturity. Both of them feature very thick necks but the males also have a thickness in the chest and shoulder regions as well. Females tend to be longer and more slender in form than the males. The males also have a crest that forms on the top of their heads. One physical characteristic that is different from other species is their long pointy nose. You will only find the Galápagos Sea Lion in 2 places. They are the Galápagos Islands and Isla de la Plata. When they aren’t in the water, they can be found on the sandy shores or rocky areas that connect to the waters. They are fun to watch because they have such a playful nature to them. They are very social and the sound you will heard from them the most is similar to the barking of a dog. There are large sub groups of bachelor males out there as well. These are the ones that aren’t strong enough to maintain an area of their own to attract females to mate with. The males are very curious which is part of the reason they may be struck by boats or get caught in fishing nets. Galápagos Sea Lions eat a variety of different kinds of fish found in the water. There seems to always be enough of it to go around as well. The males are known to attack pups as well but it is due to them defending the area more than it is to fulfill their need for food. The males known as “bulls” are the head of the colonies. They are larger than the females and can grow to measure 7 feet (2 meters) in length and weigh up to 800 pounds (363 kilograms). As the males grow larger, they begin to fight for dominance over territories including a “harem” which may contain between 5-25 females. Galápagos Sea Lions are very territorial and will fight off any intruders that may enter their territory. Each female (cow) in a harem, gives birth to a single pup a year after mating. Galápagos Sea Lion pups have a very strong bond with their mother. A single pup will be nurtured by its mother for up to 3 years following its birth. During the development of the bond, the cow & pup will learn to recognize each others bark and be able to distinguish it from the rest of the colony. While the cow is nursing her pup, she will take it with her into the waters. When the pup is 2–3 weeks old, the cow will mate again. Within the colony, Galápagos Sea Lion Pups live together in a “rookery” or nursery. Pups can be seen together napping, feeding and playing together. It is common to see one cow caring for a group of pups while the other cows go off into the waters to feed.

Galápagos Sea Lions are especially vulnerable to human activity. Their inquisitive and social nature makes them more likely to approach areas inhabited by humans and to come in contact with human waste, fishing nets and hooks. Galápagos Sea Lions consume a large amount of food each day. They tend to hunt for food within a few miles of the shore however, they have been known to go further out when they need to. The further from the shore that they are, the more likely it is that they will end up being eaten by sharks and Killer Whales. Fishermen in the area do tend to get upset over the amount of fish that these animals consume. They feel it makes it harder for them to get enough to make a decent living from. However, researchers don’t believe that the Galápagos Sea Lion is able to consume enough to be a huge problem for fishermen in the area. The males are always very competitive with each other, but even more so during the mating season. They will take presence over an area and fight other bulls to keep it. Then when the females arrive they will create harems with 5 to 20 females in it. They will breed with each of them. They will also protect them but can be aggressive towards the pups. These young pups are born soon after the females arrive to mate. Then they will mate again with the new male they are with about two weeks later. The mating season runs from May until January, which is a very long breeding period. The number of Galápagos Sea Lions out there is about 50,000 and they are very heavily protected.  One of the biggest threats to the Galápagos Sea Lions is due to El Niño. This weather event can result in large numbers of them being killed, the females may not want to mate or they will abandon their offspring. The islands where they live are very common tourist attractions. They offer a great place to observe these animals in their natural habitat. The safety of the Galápagos Sea Lions is always a priority though. Any visitors that violate the guidelines can be arrested or required to pay fines.

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