Pinnipeds (“flipper-footed”) are marine mammals possessing both front and rear flippers that although they live in the ocean are able to come onto land for significant periods of time. Members of this group include seals, sea lions and walruses. The ancestors of our current day pinnipeds were land dwellers that over time began to spend increasingly greater amounts of time in the ocean. As time passed, they developed adaptations for success in a marine environment.
True seals (phocids) are easily identifiable by their ears and flippers. Their ears are holes with no external ear flaps. They have small front flippers that are not of much use for moving on land. They have to move with a caterpillar like motion called galumphing which is essentially flopping along on their bellies. When swimming they use their rear flippers in a side to side motion like a fish tail to propel them forward.
Sea lions (otariids) are sometimes referred to as eared seals. They possess external ear flaps. In contrast to the true seals, they have large front flippers and are able to use all four flippers to “walk” on land. In the water, they propel themselves by using their front flippers like oars. I can almost always find sea lions to watch in Newport Bay.
Walruses (odobenids) are easily identifiable by their tusks. I have never seen a walrus in the wild.
Harbor Seals
Harbor seals are the most commonly encountered seals on both the east and west coasts of the United States. I can usually count on finding them at Quarry Cove in the Yaquina Head Outstanding Natural Area where they haul themselves up onto the rocks to rest.
Adults can be up to 6′ long and weigh up to 285 pounds with males being slightly larger than females. Fur color is variable but most commonly light colored with dark spots or dark colored with light rings. These seals have fairly short snouts which are a bit dog-like.
The diets of harbor seals consist primarily of fish, shellfish and crustaceans like crabs. These seals hunt by both shallow diving and deep diving depending on the nature of their prey. They are also able to sleep for up to 30 minutes underwater.
Harbor seals are mainly non-migratory typically traveling no more than 15-30 miles from where they were born. Birthing is done in nurseries where females congregate for protection from predators. I recently had the opportunity to visit one of these nurseries, the Carpinteria Harbor Seal Preserve and Rookery near Ventura, California where I saw a nice group of momma seals and their pups.
The pups weigh about 25 pounds at birth and are able to swim within minutes. After 2-3 days, they can dive for up to 2 minutes. By one month of age, they can swim for long distances. They nurse for 4-6 weeks on milk that contains about 50% fat. The photo to the left shows a mom and pup returning from a swim.
Northern Elephant Seals
Northern elephant seals are another type of real seal. They are the largest of the phocids and were hunted nearly to extinction for their blubber during the 19th Century. Populations are difficult to estimate because these animals spend most of their lives living solitarily out at sea. It is believed that there might be 250,000 of them.
I have never seen an elephant seal on the Oregon coast but have had the privilege of observing them two places on the California coast, at Point Reyes National Seashore (north of San Francisco) and at the Piedras Blancas Northern Elephant Seal Rookery (San Simeon, CA) where I recently visited during the birthing period.
Adult male elephant seals can be as large as 16 feet long and weigh up to 5,000 pounds. When they reach puberty at 5-7 years of age, they grow an inflatable proboscis, reminiscent of an elephant’s trunk, not present in young males or females. You might ask the question: what is the purpose of such a ridiculous looking facial feature?
It is believed that this appendage is used by high rank males to assert dominance. The male rears back his head, inflates his nose like a balloon, points the tip into his mouth, and uses it like a megaphone to make rhythmic, loud grunting sounds which ward off lesser males. Each male has a unique grunt that identifies him to other seals.
Males live most of their lives solitarily in the ocean foraging for food off the continental shelf, diving 24-hours a day from 500-3,000 feet where they dine on bottom-feeders. They come to land December-March for breeding and in the summer to molt. When on shore, they are social either sleeping or sparing. They will neither eat nor drink until they return to the ocean. Males threaten, intimidate and fight other males attempting to rise in social status. Only the strongest and most aggressive reach the rank of alpha.
Females can be as large as 12 feet in length and weigh up to 1,700 pounds. Elephant seals birth and mate in harems on the beach. The females give birth during January and February arriving on the beach only a few days before birthing. Pups typically weigh 60-80 pounds at birth and are 3-4 feet long. They will nurse on one of mom’s two nipples for about one month drinking milk that is up to 60% fat which allows them to grow to 250-300 pounds. At about three months, they leave the rookery beach not to return to land until the following fall. For the month she nurses her pup, a mother does not eat or drink losing about 40% of her body weight.
Alpha males become harem masters of 20-50 females. After weaning her pup, the female will be bred and leave the beach pregnant. She will return in May to molt and then spend the next 7-8 months at sea before returning to the beach to give birth. Females are essentially breeding machines.
This is a very good video about elephant seal pups:
Use this link to learn more about elephant seals: https://elephantseal.org/.