The gray seal is amongst the rarest of seals in the world. It has a rotund torso which tapers to a more slender hind end, and a layer of thick blubber for insulation against cold temperatures in the sea. Adult males feature thick rolls of flesh on their necks and chests and a concave ‘Roman’ type of nose. Gray seals have long, flat faces with big eyes, and they do not have external ears. Their front flippers are relatively blunt and short, and the hind ones are short and thick. Males are dark gray, black and brown with some lighter blotches, while females are usually light gray with darker blotches. When pups are born they have thick, creamy-white fur, called ‘lanugo’, which molts and is replaced by their adult coat when they are about two to four weeks old.
Gray seals live on both coasts of the North Atlantic Ocean, in three separate populations: the western Atlantic group is found around the coast of Canada at north Labrador down as far as New England. Those of the eastern Atlantic population are found around the United Kingdom and Irish coasts and those of northwestern Russia as far north as the White Sea. There is a Baltic population in the Baltic Sea. These seals spend the majority of their lives in coastal waters; when on land, they occur on rocky coasts, islands, and sandbars, as well as on ice shelves and icebergs.
Gray seals are diurnal animals, being active during the day and sleeping at night. They gather in large groups for mating, pupping and molting. They do not eat during the breeding period, drawing from their blubber for nutrition. They also gather together in small groups on land to rest. When foraging, however, they dive alone or with a small group. A behavior that is commonly seen is ‘bottling’ when the seal is in a vertical position in the water with only its head up above the surface. Gray seals can be quite curious about humans and boats, and will approach vessels and divers. Care must be exercised when observing seals on land as they may be aggressive, particularly during the breeding season. These seals do not migrate but they disperse widely after the mating season.
Gray seals tend to be polygynous, with males in competition to mate. Successful males mate with between 2 and 10 females, but in areas such as ice or sand where females are not so close together, one male will often mate with just one female. The mating season of the gray seal occurs from mid-December until October, depending upon where the population is located. After gestation of 11 months, females bear one pup the day after coming to shore at the rookery. Pups are nursed for 3 weeks and will remain on land until molting has taken place, living off its reserves of blubber, and then it will feed out at sea. The young generally disperse in different directions from their rookery and can wander distances of more than 1,000 km. A female gray seal is ready to breed when it is about 4 years old, while males are ready between 3 and 8 years old.
Gray seals can be legally shot as pests, as many fishermen believe that they provide competition for fish, posing a threat to stocks of fish, and that they also damage traps and nets. Illegal shooting also takes place. They are also threatened by chemical and oil pollution and often become entangled in fishing nets, which can be fatal.
According to the IUCN Red List, because of changes in population dynamics, it is difficult to estimate the total global population size of the Gray seal, but the approximate number of this species is 400,000 individuals, with specific estimates of its population in certain regions: the Baltic Sea - 22,000 seals; Canada - around 250,000 seals; UK - 117, 000-171, 000 seals; USA - 7,300 seals; Iceland - 11,600 seals; Norway - 3,100 seals; Ireland - 2,000 seals; Russia - 1,000 - 2,000 seals. Gray seal numbers are increasing today and it is classified as Least Concern (LC).