- A-Z Animals
Seals are a semi-aquatic species, also commonly referred to as pinnipeds. There are three general categories of seals, classified as Phocidae, consisting of the true seals, Otariidae, consisting of fur seals and sea lions, and Odobenidae, which currently includes only walruses. They are easily recognized from their finned feet and distinct build, allowing them to thrive in the sea.
These animals have long captured the public consciousness due to their striking appearance and playful nature and are prominently featured in exhibits worldwide.
There are 34 known species of seals in the world. These consist of 18 true or earless seals, 15 eared seals, which include fur seals and sea lions, and the walrus.
Size: Length: 3 -16 ft (1 – 5 m)
Weight: 99 – 7100 lb (45 – 3200 kg)
The Baikal seal is the smallest at 3ft and 99lbs, while the male Southern Elephant seal is the largest, measuring 16ft and 7100lbs.
Flippers: All seals have four fin-like appendages called flippers, which help them move on land and sea. Seals and walruses have shorter flippers, while sea lions have longer ones.
Ears: Only the otariids have external ears, as evident from their name eared seals. On the other hand, the phoecids and walruses lack external ear flaps and have only ear holes.
Teeth: They have fewer teeth than most carnivores, especially incisors and molars, but have pointed, sharp canines. Walruses have two very easily identifiable protruding tusks.
Body and Coloration: Males are generally larger than females, except for some like crabeater and leopard seals. They have a streamlined and spindle-shaped body, alongside rounded heads, short snouts, and small tails. Most of them are covered with dense fur and have whiskers.
While colors widely vary from white to brown to gray to black, a general characteristic among all seals is that the dorsal region is darker while the ventral area has a lighter shade.
They are found in seas and oceans worldwide, mostly preferring the colder waters of the Arctic and Antarctic regions. Some are also found in inland lakes in Finland, Russia, and Siberia. The exceptions are the monk seals, which live in tropical waters, and the Baikal seal, which is exclusive to the freshwater lake Baikal.
Though they spend long periods in water, they will come on land for short periods to rest, breed, or shed. Those living in polar regions can be spotted on ice floes or large floating ice sheets, while those in more temperate climes are seen on boulders or rocky outcrops close to the sea.
Seals have high longevity and can live up to 25-30 years. The longest living seal recorded is a female Gray seal off the coast of the Shetland Isles in Scotland who lived up to 46 years.
Some pinnipeds have more specific tastes, such as the crabeater seal, which, contrary to its name, is a filter feeder sustaining on krill. The walrus uses its teeth to feed on clams.
Seals mate annually and are generally promiscuous, though monogamy has been observed in certain species. Breeding can take place both on land and sea after forming a colony. Both sexes build up extra blubber reserves – the males need additional energy for courting a mate and warding off competitors, while the females need it to nurse and take care of their newborns.
Courtship varies from species to species, as some, like the California sea lions, use a lek system while others, like the male northern fur seal, maintain entire territories between which the females can freely move.
After breeding, the females will give birth to a single pup. They then have to take care of the baby seals independently as males do not generally help raise the offspring. The mother will haul on land to nurture and feed the young, fasting during lactation, with walruses being the only exception as they wean their pups at sea. Once the weaning period is over, she abandons the pup, leaving it to fend for itself.
Baby seals reach up to three times their weight during feeding and use the excess fat to strengthen themselves to survive. This is a precarious period for them, as they become easy prey for killer whales, polar bears, and other seals. During this time, pups do not eat or drink, surviving off the body fat provided to them while weaning.
Males reach sexual maturity at around 3 – 4 years of age, while females do so at 3 – 6 years.
According to the IUCN’s classifications, seven seal species are “Endangered” or “EN” including the Hawaiian fur seal, the Galapagos fur seal, and the Australian sea lion. Three are categorized as “Vulnerable” or “VU” – the northern fur seal, the hooded seal, and the walrus. There are several threats to them, including getting caught in fishing nets, global warming causing habitat loss, marine pollution, and indiscriminate hunting for their blubber, fur, and meat.
There have been several acts passed to protect seals. These include the Marine Mammal Protection Act of 1972 (MMPA) in the United States and the Convention for the Conservation of Antarctic Seals.
A baby seal is called a pup.
Not in particular, but they are wild animals and should be avoided.
No, they are entirely separate species.
There are several differences between the two. Seals are less mobile on land, make less noise, and have longer hind flippers. On the other hand, sea lions have better terrestrial mobility, bark to communicate, and have smaller hind limbs.
Due to their high intelligence, seals will appear friendly and sometimes, out of curiosity, will approach humans. However, this behavior should not be encouraged as they may act in an unpredictable manner that harms both parties.
They are commonly called a colony or a rookery, but other terms include a bob, a harem, or a herd.
Seals have several predators, including sharks, polar bears, killer whales, and other seals.
Though rare, attacks on humans have been recorded, with a single recorded incidence of fatality in 2003. Researcher Kirsty Brown was dragged underwater by a leopard seal, drowning as a result.
Yes, seals can bite if they feel threatened.
No, the oxygen from their lungs gets compressed and is sent to the muscles and blood.
Yes, in fact, penguins form the greater part of the diet of seals, like the leopard seal and the fur seal.