Seals are a diverse group of semi-aquatic mammals in the Order Carnivora. The size of seals ranges from 3 feet 3 inches for the Balkan seal to 16 feet for the southern elephant seal which ranks as the largest carnivoran. The streamlined bodies of seals feature four limbs which have been modified to function as flippers. When compared to dolphins, seals are more agile and flexible. Most seal species inhabit the cold waters of the Southern and Northern Hemispheres. The animals mate and give birth on the shores and also escape to the beaches from predators such as killer whales and sharks.
Mediterranean monk seal
The Mediterranean monk seal is classified in the Phocidae family. It grows from about 2.6 feet in length at birth to an average of 7.9 feet in adults. Reproductive maturity for the seal is reached at roughly age four while the average lifespan falls between 20 to 25 years. The animal formerly had a wide range of habitat which included all of the Mediterranean offshore islands, the Black Sea, and the Atlantic and its islands. Its current habitat range has reduced, and it now includes the Cabo Blanco region in the northeastern Atlantic Ocean, the Aegean Sea, and the Madeira archipelago. It is estimated that fewer than 700 individuals continue to survive.
Hawaiian monk seal
The Hawaiian monk seal mainly inhabits the northwestern Hawaiian Islands including the Laysan and Lisianski Islands, Kure Atoll, Peral and Hermes Reef, and the Midway Islands. The animal has a preference for warm subtropical waters. It moves to land to breed as well as haul-out on the sand, volcanic rock, and corals. The seal feeds on fish, crustaceans, eels, and cephalopods, and other benthic organisms. The seal was almost rendered extinct by large-scale hunting in the 19th century and it still recognized as endangered.
Northern elephant seal
The northern elephant seal is categorized in the Phocidae family and it one of the elephant seal's two species. The animal is named for its great size as well as the large proboscis sported by males that are used in making loud roaring noises, particularly during the mating competition. The females can reach 11 feet compared to the male's 14 feet, and a successful male can impregnate a maximum of 50 females in a single season. The seal is commonly sighted in the eastern Pacific Ocean with important breeding sites existing at the Farallon Islands, Channel Islands, Piedras Blancas Light, and the Año Nuevo State Reserve in the US and Mexico's Isla Cedros and Isla Benito del Este.
Southern elephant seal
The southern elephant seal is the other species of the elephant seal. The animal ranks as the largest aquatic mammal after the bigger cetaceans, and it is the largest seal as well as the largest carnivoran. The seal has a shorter proboscis and a larger body mass than the northern elephant seal. The male measures 14 to 19 feet and 8.5 to 9.8 feet for the females. The seal's breeding colonies are distributed in the Atlantic, Indian, and Pacific Oceans. Elephant seals can live on land for long stretches of time unlike other seals, and they can remain dry for some consecutive weeks annually. The seal's prey includes krill, mollusks, cephalopods, nothothens, and crustaceans.
The Ross seal inhabits ice packs around the Antarctic. It is characterized by long fore and hind flippers, very short fur, and a fairly small head with a wide and short blunt-ended snout. After its yearly molt, the seal's fur coat becomes silver on the belly and dark greyish/black on the back with brown to reddish streaks extending from the lower jaw to the chest. The coat may then fade to a brownish color throughout the year. The animal is mostly solitary, and it does not form big colonies like other seals to breed. Mating occurs in late December following which a single pup is born the following year.
The crabeater seal is recognized as the world's most abundant seal species with possibly as numerous as 75 million individuals. The abundance is attributed to its specialized predation of the Southern Ocean's abundant Antarctic krill by the use of its sieve-like tooth structure. Adult seals have an average length of 7.5 feet and an average weight of 440 lb. Females are 2.4 inches longer than males. The animal's body is fairly slender with long snouts and skulls in comparison to other phocids. The seals have a circumpolar distribution around the Antarctica although they may wander to the extreme southern coasts of New Zealand, Africa, South America, and Australia.
The leopard seal appears large and muscular. Its stomach is light grey while its back is dark grey. The seal's throat is whitish, and it features black spots which give the animal its name. The leopard seal's size falls between 7.9 to 11.5 feet and 440 to 1,310 lbs for its weight. The seal's molars are fashioned like those of the crabeater seal in that they can lock together to sieve krill from the water. The leopard seal occupies the cold waters around the Antarctic, and it is ranked second to the killer whale among the main predators of Antarctica.
The Weddell Seal has a spindle-shaped body which appears dark-silver gray and is lighter below and which is mottled with white, black, and grey blotches. The seal's coat can fade to brownish during summer. The Weddell Seal lives on pack ice and the shorelines of Antarctica. The animal is an excellent diver and can reach depths of more than 600 meters and stay underwater for up to 82 minutes. The seal also boasts excellent underwater vision, and it has a nictitating membrane which shields its eyes from blowing snow and salt water.
The bearded seal inhabits the Arctic Ocean and its shores. Its generic name is inspired by the Greek words eri and gnathos used about its heavy jaws. The seal is called bearded due to its prominent and abundant whiskers. The whiskers curl quite elegantly when they are dry giving the animal a "raffish look." Bearded seals represent an essential food source for the predatory polar bears and also for the Inuit of the Arctic coast. Bearded seals feed on small prey present along the ocean floor including fish, clams, and squid. The animal's whiskers act as feelers in the sediments.
The hooded seal's name is inspired by the inflatable hood present on the forehead of an adult male. The seal inhabits the deep waters in the extreme north of the Atlantic Ocean. The hooded seal has a silver or bluish grey coat with scattered black blotches and spots. Its flippers are heavily clawed while its foreflippers are useful in steerage and not propulsion. The hooded seal is fairly antisocial, and it only congregates during breeding and molting. The pups of the hooded seal are born in a uniquely advanced developmental form and are weaned after four days which is the shortest lactation time acknowledged for any mammal. The pup survives on its fat reserves while on the ice after the mother abandons it.
The harbor seal inhabits the Northern Hemisphere's Arctic and temperate marine coastlines. It ranks as the most distributed among the seals with a presence in the coastal waters of the Pacific Ocean, Baltic Sea, Atlantic Ocean, and the North Sea. The seals appear tan, brown, gray, or silvery white with characteristic V-shaped nostrils. An adult harbor seal can measure 6.1 feet. Harbor seals commonly inhabit rocky areas to avoid predation and extreme weather conditions. The pups can dive and swim a few hours after birth and develop rapidly due to the fat-rich milk given by their mothers.
The spotted seal has a pale underside with the rest of the body having dark silver of grey. Its coat possesses a pattern of dark spots which are evenly distributed throughout the body. Its head is round with a narrow snout and narrow and short flippers. The spotted seal is sighted near the North Pacific Ocean as well as far north the Arctic Ocean. The animal lives on the southern fringes of the pack ice beginning winter to early summer after which it relocates to coastal regions. Although hunting of the seal is acknowledged, it does not appear to affect its population size greatly.
The ringed seal lives in both the Arctic and sub-Arctic regions, and it sighted in the Hudson Bay and the Baltic and Bering Seas. It is the smallest of the Arctic seals, and it has a small head, a plump body, and a short cat-like snout. The animal's coat appears dark with silver rings on the sides and back, and a silver belly. The ringed seal's length is 5 feet on average. The seal commonly rests on an ice floe, and it will relocate farther north in search of denser ice. The ringed seal's prey includes herring, mysids, arctic cod, and shrimp while its predators include the Greenland sharks, polar bears, glaucous gulls, and the Arctic fox.
The Baikal seal is recognized as the only pinniped limited to freshwater habitats. Its torpedo-shaped flexible body makes it a graceful swimmer while its powerful hindquarters propel the seal through the water. Adult Baikal seals dense sports fur which appears dark silver-grey on the upper parts and yellowish-grey on the undersides. A thick layer of blubber resides under the seal's body which provides both buoyancy and insulation. The animal only inhabits Russia's Lake Baikal which is recognized as the world's oldest and deepest lake.
The Caspian Seal is uniquely restricted inland that is the landlocked Caspian Seal. Its upperparts range from greyish-yellow to dark grey with lighter grey sides and belly while the back has irregular dark spots. The seal's pups are born with a white and long woolly coat which is replaced with dark and short grey hair after three weeks. The seal feeds on kilka and crustaceans among other small fish while it is vulnerable to predation from large eagles and wolves. The seal's gestation period is estimated at 11 months. The Caspian seal is listed as endangered, and it is especially vulnerable since the Caspian Seal is a closed habitat.
The harp seal is indigenous to the northernmost regions of the Atlantic Ocean and some areas of the Arctic Ocean. Its body appears silvery-gray with wishbone-shaped or black harp marks on its back. The pup is born with a yellowish-white coat which becomes white after three days for two to three weeks. Adults reach 5 feet 7 inches in length. The seal prefers to stay in the ocean and spends fairly little time on land. Harp seals are very social, and they can be quite noisy. Female harp seals are ready to mate at five or six years after which they bear a single pup yearly mostly in late February. The harp seal's conservation status is listed as least concern.
The gray seal inhabits the shores of the North Atlantic. The gray seal is large, and the eastern Atlantic bulls can reach lengths of 8.2 feet to 10.8 feet with the females being 5.2 to 6.6 feet long. The gray seal preys on fish, majorly demersal or benthic species, obtained at depths down to 230 feet or more. Other prey includes wrasse, sand eels, lobsters, gadids, herring, skates, and flatfish. Its pups sport a silky white fur, and they fatten fast owing to their mother's fat-rich milk. The seals are protected in the US as well as in the UK.