The grey seal is among 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.
Read Pritish Kumar Halder illustration of Grey Seal, its distribution, lifestyles and threats.
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.
Habits and Lifestyle
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. This seals 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.
Diet and Nutrition
Gray seals feed on a wide variety of crustaceans such as shrimp, as well as fish, squid and octopus.
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 become entangled in fishing gear and other types of marine debris resulting in seals swimming off with the gear attached or becoming anchored. They can become entangled in many different fishing gear types including gillnets, trawls, purse seines, and weirs. Once entangled, seals may drown if they cannot reach the surface to breathe, or they may drag and swim with attached gear for long distances. This can ultimately result in fatigue, compromised feeding ability, or severe injury, which may lead to reduced reproductive success and death.
Gray seals are easy to view in the wild, but this puts them at higher risk of harassment and in some cases, even intentional human-related injuries and death. Feeding (or trying to feed) them is harmful and illegal. It changes their natural behaviors and makes them less wary of people and vessels. They learn to associate humans with an easy meal and change their natural hunting practices—for example, they take catch bait directly off fishing gear. Sometimes they fall victim to retaliation (such as shooting) by frustrated boaters and fishermen.
They may also be disturbed or harassed by the presence of humans and watercraft. Harassment is illegal and happens when any act of pursuit, torment, or annoyance might injure them or disrupt their behaviors. Remember to share the shore with gray seals for their safety and yours.
Contaminants enter ocean waters from many sources, including oil and gas development, wastewater discharges, urban runoff, and other industrial processes. Once in the environment, these substances move up the food chain and accumulate in predators near the top of the food chain such as gray seals. These contaminants accumulate in gray seals’ blubber stores, threatening their immune and reproductive systems.
Oil spills and energy exploration
Oil spills can harm gray seals. If exposed to oil, a gray seal’s fur can no longer repel water. This makes it difficult for the seal to swim, float, and keep warm. Inhaling or swallowing oil can also damage a seal’s respiratory, digestive, reproductive, and central nervous systems. Oil can also irritate or burn the seal’s skin.
Vessel and Vehicle Interactions
Gray seals are susceptible to water vessel and land vehicle impacts. Inadvertent vessel strikes can injure or kill gray seals. Gray seals are vulnerable to vessel collisions throughout their range, but the risk is much higher in some coastal areas with heavy vessel traffic. Due to gray seal behavior, seals are also vulnerable to vehicles that drive on beaches, which is common in some areas of high gray seal density. Vehicular strikes are often fatal to seals, particularly pup or young seals that haul out high on the beach.
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.
- The scientific name for the Gray seal comes from the Greek and it means ‘hooked-nose sea-pig’.
- Typically making dives as deep as 70 meters when foraging, Gray seals can also go to depths of about 300 meters.
- Mother and baby seals form a strong bond at birth. A mother recognizes her pup by its call and scent. During its first few weeks of life, the mother feeds it about 6 times per day, up to 10 minutes each time.
- Gray seals have webbed flippers. The strong rear flippers propel them through the water, and they use their tail to steer.
- These seals can stay underwater for as long as 16 minutes. They are unable to breathe underwater but can stay under for this amount of time by slowing their heart beat to conserve oxygen.