The gray seal is a large species of earless seal belonging to the Phocidae family of so-called true seals. Its scientific name is Halichoerus grypus, and it is the only member in the genus Halichoerus. The species inhabits both sides of the Atlantic Ocean. The species is also known as the Atlantic seal or the horsehead seal.
The Atlantic seal is a relatively large earless seal. Bulls can reach lengths of up to 3.3 meters and weigh up to 300 kg. In the western part of the Atlantic Ocean, males are known to reach even 4 meters. Females are smaller, reaching 2 meters and weighing up to 200 kg. While similar in appearance with the harbor seal, there are differences in the shape of the head, which has a straight profile, the nostrils are further apart, and there are also fewer spots on the body.
The Atlantic seal breeds on many coasts in the Eastern part of the Atlantic, and especially on the coasts of the UK and Ireland. There are colonies numbering up to 6,000 individuals in islands such as the Farne Islands. These seals can also be found on the German Bight or German Bay. In the western Atlantic, seal populations exist from the northern waters of Canada to the south, reaching the New Jersey state in the US. There are also some isolated populations in the Baltic sea, with specimens being allocated to a distinct subspecies, H. grypus balticus.
The gray seal feeds on many species of fish, as well as crustaceans. They mostly hunt for benthic fish such as rays, with a preference towards the sand eel fish, Ammodytes sp. Atlantic seals also feed on cod and herring, yet they have been observed to feed on whatever species are available at a particular time. These seals have been seen eating lobsters and octopuses as well as hunting larger animals such as harbor porpoises and harbor seals.
The Atlantic seals breed mostly on sandy beaches. Females give birth to a single pup from September to November in the eastern part of the Atlantic and from January to February in the western part. Gray seal pups weigh 14 kg when born, and they will quickly grow in size and store fat, thanks to the fat-rich content of cow milk, which can have as much as 60 percent fat.