The sea lion is the largest member of the Otariidae family, the “eared seals” that includes all sea lions and fur seals. It is the only member of the genus Eumetopias. Eared seals differ from molluscs, the “true seals”, by having external ear flaps, long flipper-like forearms used for propulsion, and rotating rear flippers that allow quadrupedal locomotion on land.
View origin and description
Photo: Sea lion
Sea lions, or eared seals, are one of the three main groups of mammals in the taxonomic group of pinnipeds. Pinnipeds — they are aquatic (mostly marine) mammals, which are characterized by having both forelimbs and hind limbs in the form of fins. In addition to sea lions, other pinnipeds are walruses and fur seals
The sea lions are one of two groups of seals (any pinnipeds except walruses): earless seals, which include the taxonomic family of true seals (Phocidae), and eared seals, including the family of eared seals (Otariidae). Walruses are usually considered a separate family of pinnipeds, Obobenidae, although they are sometimes included in molluscs.
Video: Sea Steller
One way to distinguish between the two main groups of seals is by the presence of the pinna, a small, furry ear bud (outer ear) found in sea lions and absent in true seals. True seals are called “earless seals” because their ears are hard to see, while sea lions are called “eared seals”. The name “otariid” comes from the Greek “otarion” meaning “little ear”, referring to the small but visible outer ears (pinnas).
In addition to the pinna, there are other obvious differences between sea lions and true seals. Sea lions have hind fins that can be flipped under their bodies to aid their movement on the ground, while true seals' hind fins cannot be turned forward under their bodies, resulting in their slow and awkward movement on the ground.
The sea lions also swim using their long front flippers to propel themselves through the water, while true seals swim using their back flippers and lower body in a side to side motion. There are also behavioral differences, including in the breeding system.
Appearance and Features
Photo: What a sea lion looks like
The shiny-skinned sea lion is called the “sea lion” because of the light mane of coarse hair found on the male's neck and chest, resembling a lion's mane. It is sometimes mistaken for a seal, but it is easy to tell the difference. Unlike seals, the external pinnae of the sea lion cover their ears to protect them from water. Sea lions also have a bony structure that allows them to walk on all their fins, supporting their entire weight.
Fun fact: As the world's largest sea lion, an adult sea lion can reach a length of two to three meters. Females weigh between 200 and 300 kilograms, while males have been found to reach up to 800 kilograms. One massive sea lion weighed nearly one ton.
The average sea lion pup weighs around 20 kilograms at birth. At birth, Steller's pups have thick, coarse, almost black fur with a frosty appearance because the tips of the hair are colorless. The color brightens after the first molt at the end of summer. Most adult females are back-colored. Almost all males remain darker on the front of the neck and chest, some even reddish in color. Adult males have prominent foreheads and muscular necks.
Interesting fact: In the water, the sea lion swims with the help of a breaststroke and can reach a maximum speed of about 27 km/h.
The sound of a sea lion — it is a chorus of the low-pitched “roar” of older people mixed with the “lamb” vocalizations of young puppies. California sea lions can often be heard among the sea lions in southeast Alaska, their “barking” sounds are a distinctive clue to finding these smaller, darker sea lions.
Where do sea lions live? ?
Photo: Kamchatka sea lion
Sea lions prefer the colder temperate climate to the subarctic waters of the North Pacific. They need both terrestrial and aquatic habitats. They mate and give birth on land, in traditional places called rookeries. The rookeries usually consist of beaches (gravel, rock or sand), ledges and rocky reefs. In the Bering and Okhotsk seas, sea lions can also pull out sea ice. In the northern part of the Pacific Ocean, the dwelling of the sea lion can be found along the coast of California to the Bering Strait, as well as along the coasts of Asia and Japan.
The world population is divided into two groups:
- eastern;
- western.
Sea lions are distributed mainly along the North Pacific coast from northern Hokkaido, Japan through the Kuril Islands and the Sea of Okhotsk, the Aleutian Islands and the Bering Sea, the southern coast of Alaska and south to central California. Although they are most commonly found in coastal waters on the continental shelf, they also occasionally forage on much deeper continental slopes and in pelagic waters, especially during the non-breeding season.
Canadian residents are part of the eastern population. In Canada, on the offshore islands of British Columbia, there are three main breeding areas for sea lions, located on the Scott Islands, on Cape St. James and offshore from the Banks Islands. In 2002, about 3,400 puppies were born in British Columbia. During the breeding season, the total population of animals living in these coastal waters is approximately 19,000, with about 7,600 of them at breeding age. This is the most powerful breed of males with several females.
Sea lions breed along the North Pacific from Agno Nuevo Island in central California to the Kuril Islands north of Japan, with the highest concentration of rookeries in the Gulf of Alaska and the Aleutian Islands.
Now you know where the sea lion lives. Let's see what this seal eats.
What does a sea lion eat?
Photo: Sea Steller
Sea Stellers are carnivores with sharp teeth and strong jaws that eat their prey. They catch their own fish and eat what is most available in their area. In British Columbia, the sea lion eats mostly schooling fish such as herring, hake, salmon, and sardines. Sometimes they dive deeper to catch sea bass, flounder, as well as squid and octopus.
Fun Fact: Sea lions are excellent swimmers who sometimes dive to depths of over 350 meters in search of food and usually stay submerged for no more than five minutes at a time.
Adult sea lions feed on a variety of fish, including Pacific herring, gerbil, Atku mackerel, pollock, salmon, cod, and stonefish. They also eat octopus and some squid. On average, an adult sea lion requires about 6% of its body weight per day. Young sea lions require twice as much food.
Sea lions also kill fur seals and other animals. On the Pribilof Islands, young male sea lions have been observed killing and eating northern fur seal pups, while elsewhere they have occasionally eaten ringed seals. Due to their diet, sea lions can influence the populations of fish, bivalves, gastropods and cephalopods.
Character and lifestyle features
Photo: Sea lion in nature
Sea lions are mammals, so they need to come to the surface to breathe air. They spend part of their time on land and go out into the water to hunt for food. Sea lions prefer the coastal shelf area within 45 km from the coast, although they can be found more than 100 km from the coast in waters over 2000 m deep. They do not migrate like some seals, but move seasonally to different feeding and resting places.
Sea lions are usually sociable and are found in large groups on beaches or rookeries. They usually live in groups of two to twelve, but sometimes up to a hundred individuals are found together. At sea, they are solitary or move in small groups. They forage at night offshore and in pelagic waters. Sea lions can travel long distances during the season and can dive to depths of up to 400 m. They use the ground as places to rest, molt, mate, and give birth. Sea lions produce a powerful vocalization, accompanied by a vertical shaking of the head in males.
Breeding sea lions is one of the most massive spectacles of nature. When these giants crash on the shore, their favorite beaches, called rookeries, disappear under their bodies. Young puppies are sometimes crushed by the crowd and not listened to by powerful males for the sole purpose. Males must establish and maintain a rookery territory in order to breed. Most of them don't do this until they are nine or ten years old.
Social structure and reproduction
Photo: Sea lions in water
Sea lions are colonial breeders. They have a polygynous mating system in which only a small proportion of mature males father most of the puppies at certain times of the year.
The mating season for the sea lion is from late May to early July. At this time, the female returns to her home rookery — an isolated rock where adults gather to mate and give birth to a child – to give birth to one puppy. During the mating season, sea lions congregate in dense colonies for safety, away from terrestrial predators. The sounds of adults and the bleating of newborn puppies create a loud protective noise. This collective and constant noise deters possible predators.
A female sea lion takes care of her pup for one to three years. The mother stays on land with her pups for one day and then goes to sea to collect food the next day. She follows this model to feed her pups while continuing to support her own nutrition.
A newborn sea lion is a nimble little creature. He can crawl from birth and learns to swim at about four weeks of age. While this is somewhat difficult to estimate, it appears that the mortality rate for puppies is quite high and may be the result of older animals being forced out or, in cases where they are forced to leave the rookery, they find themselves unable to swim and drown.
Puppies develop immunity to most diseases while they are breastfed. As puppies mature and wean, they can become sick due to internal parasites (such as roundworms and tapeworms) that affect growth and lifespan. A female sea lion is keenly aware of her pup's needs, never leaving her for more than a day at a time, during the critical first month of her life.
Natural enemies of sea lions
Photo: Sea Lion Steller
For many years, human activities such as hunting and killing have posed the greatest threat to sea lions. Fortunately, these are also the most avoidable risks. This large creature is also prone to accidental entanglement in fishing gear and can be suffocated by debris around their necks. A entangled sea lion can potentially drown before it can escape or free itself.
Pollution, oil spills, and environmental pollution such as heavy metals threaten sea lion habitats. This preventable harm can lead to the displacement of inhabitants from their vital habitats and, ultimately, to a reduction in their numbers.
The sea lion also faces natural threats such as reduced food availability. In addition, killer whales prey on them. As with all animals, the disease poses a potential risk to the sea lion population.
Scientists are currently investigating why sea lion populations are declining. Possible reasons for this include an increase in parasites, disease, predation by killer whales, food quality and distribution, environmental factors, and nutrient deficiencies caused by natural changes in the abundance of key prey species or competition with other species or humans for food.
Population and species status
Photo: What a sea lion looks like
The two sea lion populations represent different genetic, morphological, ecological, and population trends. The population trends of eastern and western populations differ for complex reasons. Simply put, the difference is likely a result of the different types and magnitudes of threats faced by the species throughout its range.
The western population includes all sea lions originating from rookeries west of Cape Saklinga. The sea lion population has declined from about 220,000 to 265,000 animals in the late 1970s to less than 50,000 in 2000. While the population of the west as a whole has grown slowly since about 2003, it is still rapidly declining over large areas of its range.
The eastern population includes sea lions originating from rookeries east of Suckling Point. Between 1989 and 2015, numbers in the east increased at a rate of 4.76% per year, based on analysis of pup numbers in California, Oregon, British Columbia, and southeast Alaska. More than 80% of the sea lion population disappeared from Russia and most Alaskan waters (the Gulf of Alaska and the Bering Sea) from 1980 to 2000, leaving fewer than 55,000 individuals. Sea lions are listed in the Red Book as endangered in the near future.
Threats to sea lions include:
- strike from a boat or ship;
- pollution;
- habitat degradation;
- illegal hunting or shooting;
- offshore oil and gas exploration;
- interaction ( direct and indirect) with fishing.
The direct impact on the fishery is largely due to fishing gear (drift and gillnets, longlines, trawls, etc.) that can entangle, hook, injure or kill sea lions. They were seen entangled in fishing equipment, in what are believed to be “serious injuries”. The indirect impacts of fishing include the need to compete for food resources and possible modification of critical habitat as a result of fishing activities.
Historically, threats have included:
- hunting for their meat, hides, butter and various other products (in the 1800s);
- bounty killing (in the early 1900s);
- killing to restrict their predation on fish in aquaculture establishments (fish farms). But the intentional killing of sea lions was not allowed, as they were protected under the Marine Mammal Protection Act.
Sea lion conservation
Photo: Sea lion from the Red Book
To continue to grow their population, sea lions need constant protection of their habitat. Although sea lions in Canada have suffered from many years of hunting, since 1970 they have been protected under the Federal Fisheries Act, which prohibits commercial hunting of sea lions. There have been cases where permits have been issued to kill sea lions in an attempt to protect the fish farms that the animals prey on.
The Oceans Law, founded in 1996, protects the habitat of marine mammals. Special breeding rookeries have additional protection under the National Parks Act of Canada and as part of a provincial ecological reserve.
Protection zones, catch limits, various procedures and other measures have been put in place around large catches and haulouts of sea lions to protect their critical habitat. A critical habitat has been designated for sea lions as a 32 km buffer around all major catches and rookeries, as well as their associated land, air and water zones and three major offshore foraging areas. The National Marine Fisheries Service has also designated exclusion zones around haulouts and implemented a complex set of fishery management measures designed to minimize competition between the fishery and the endangered population of sea lions in critical habitats.
The sea lion is considered «king« #187; sea lions. This hefty mammal usually travels alone or in small groups, but joins others for protection during mating and birth. Little is known about its oceanic lifestyle, however, the good news is that since the sea lion was first protected in 1970, the adult population has more than doubled.
