California sea lions and northern elephant seals are two examples of pinnipeds. Although both belong to the family pinnipedia they are very different. Below you will find a comparison and contrast of these two different animals.
Northern Elephant Seals
Northern elephant seals, also known as Mirounga angustirostris are one of the largest pinnipeds, second only to the southern elephant seal ( M. leonina). This species belongs to the "true seals" category, meaning that they do not have external ear flaps and can not walk on all fours, but must drag themselves around on their stomachs. These remarkable creatures are found off the coast of Baja, Mexico to Point Reyes, California (although during their time at sea the males venture to Alaska). They only come ashore twice a year, once to molt and once to breed. Females and juveniles are on land molting during April and May, the sub-adult males are molting between May and June, and the adult males molt between July and August. The males then come ashore again in late November to set up breeding territories and the females arrive on the beach to give birth in December and they remain on the beach until March. After the females give birth they stay with their pup for about 4 weeks and fast, losing a great deal of their body weight and energy supply. Males also fast during this time period.
This picture is a great illustration of the sexual dimorphisim of this species (picture from friends of the elephant seal). The males range from 14-16 feet and can weigh up to 2.5 tons. The females range from 10-12 feet and weigh between 1200 and 2000 pounds. Pups are born weighing around 70 pounds. Males are easily distinguished from their females not only by their larger size but also by their more pronounced nose (probuscis) which is absent on the females.
Northern elephant seals are amazing divers. They typically dive up to 20 minutes and down to a depth ranging from 1,000 to 2,000 feet with a maximum depth recorded at 5,015 feet (parks). During these dives they are known to feed on squid and small sharks. They also feed on rat fish, rays, skates, and small sharks.
California Sea Lion
California Sea Lion also known as Zalophus californianus is a pinniped that is found in the North Pacific from Southern British Columbia to Northern Mexico. This is also a sexually dimorphic species but to a lesser extent then the northern elephant seal. The picture illustrates the sexual dimorphisim (picture is from picture). Females are around 6 feet and 200 pounds while the males range from 6 to 8 feet and 440 to 880 pounds. The pups are born 2.6 feet long.
This species congrigates on rocky and sandy beaches of coastal islands and mainland shorelines, breeding from May to July. While on land this animal walks on all fours unlike the northern elephant seal who must slide around on its stomach. California sea lions and all other sea lions belong to the eared seals category, meaning they have external ear flaps and are able to walk on all fours. In water these seals move their pectoral flippers in an up and down motion to swim and have been found to reach a speed of 25mph in short bursts (whaletimes and seaworld).
When they are on land this creature forms groups called colonies and they form smaller groups called rafts while they are in the water. This is different then the northern elephant seal who wander alone when they are in the water and only socialize while they are on land. The picture is a great example of how social these animals are in the water and how they swim (picture from earth window).
Another difference between the California sea lion and the northern elephant seal is how far they are from the mainland when they are in the water. California sea lions are rarely found more than 10 miles offshore and typically dive to 1200 feet. Female northern elephant seals are open water creatures while the males typically stay next to the continental shelf, and they typically dive deeper then 1200 feet. They also have different diets then the northern elephant seal. Both species feed on squid, but the California sea lion is also know to feed on octopus, hake, herring, and anchovy
A huge difference lies in the way the females take care of their pups. California sea lions unlike northern elephant seals do not have a fasting time. After they give birth, they leave their pup in the harem in search of food, calling and sniffing for her pup when she returns. This behavior allows the mother to have more time with her pup then northern elephant seal females are able to.
K. West - 5/25/00