Gray Seal - Oceana

Marine Mammals

Gray Seal

Halichoerus grypus


North Atlantic Ocean and Baltic Sea


Coastal Waters

Feeding Habits

Foraging Predator


Order Carnivora, Family Phocidae


The gray seal lives in North Atlantic waters and is divided into three distinct stocks — the North Atlantic stock, the Baltic Sea stock and the eastern North Atlantic stock. In these waters, gray seals experience cold temperatures and sub-arctic environments. Males will come ashore, including onto ice, to mate, often competing with each other for access to females. Females remain on land at pupping sites called rookeries to nurse newborn pups. These pups, which are born with stark white fur, look unrecognizable next to the parents but will quickly shed this fur for the mottled brown and silver fur that adults have. From birth to three weeks old, a gray seal pup may gain up to three pounds a day feeding on the mother’s nutrient-rich milk. A pup can survive off blubber reserves for several weeks as it waits to shed its lighter fur before going to sea and dispersing across large areas. Male gray seals can reach 10 feet long and more than 850 pounds, while females are slightly smaller at 7.5 feet long and 550 pounds.

When not on land, adult gray seals visit the water to hunt for food, like fish, crustaceans, squid and octopus, gobbling up between four to six percent of their body weight every day. A gray seal can dive to depths of up to 230 feet on average to swallow fish and other creatures, or to bring larger food to the surface to break up in pieces for eating. A gray seal can hold its breath for more than an hour at a time. Groups of gray seals will sometimes engage in “social feeding,” in which several individuals work together to better prevent prey from swimming away. Gray seals can fall prey to killer whales and sharks as they rest on the water’s surface, keeping their head and neck above the water to breathe.

Gray seals are considered of least concern by the IUCN Red List. However, these marine mammals are known to get caught up in fishing nets and are even targeted by fishermen in certain areas. Some countries allow gray seals to be legally killed to control populations and reduce the seal’s impact on commercially important fish stocks that may make up the seal’s diet. Gray seals are protected in the United States by the Marine Mammal Protection Act (MMPA), but continue to be threatened by boat strikes, dangerous fishing gear and marine debris.

Fun Facts About Gray Seals

1. Gray seals grow to a maximum length of 10 feet (3 m) and weight of 880 pounds (400 kg).

2. Gray seals live for 25 to 35 years.

3. Female gray seals are gray with black spots while males are black with gray spots.

4. The gray seal’s scientific name, Halichoerus grypus, translates to “hooked-nosed pig of the sea,” in reference to the male’s distinct, horse-shaped nose.1

5. Gray seals dive underwater for a maximum time of 30 minutes.

6. Gray seals typically dive in shallow waters but have been recorded diving down to 1,352 feet (412 m) in some areas.

7. Gray seals can spend more than two days out at sea foraging for food.2

Engage Youth with Sailors for the Sea

Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.

Kids Environmental Lesson Plans


1 NOAA Fisheries

2 IUCN Red List