The grey seal (Halichoerus grypus), or gray seal in the United States, is a large seal of the family Phocidae, which are commonly referred to as "true seals" or "earless seals". The only species classified in the genus Halichoerus, it is found on both shores of the North Atlantic Ocean. In Latin, Halichoerus grypus means "hook-nosed sea pig". The grey seal is large and heavy, with individuals from the eastern Atlantic being 1.6–2.3 m (5 ft 3 in – 7 ft 7 in) long and weighing 100–310 kg (220–680 lb), while individuals from the western Atlantic are up to 2.7 m (8 ft 10 in) long, and can reach a weight of as much as 400 kg (880 lb). It is found widely across the northern Atlantic, ranging from the US to Russia, and occasionally as far south as Portugal. It can be divided into two subspecies: the Baltic grey seal (Halichoerus grypus grypus), found in the Baltic Sea, and the Atlantic grey seal (Halichoerus grypus atlantica), found everywhere else. The largest populations are in Canada and the UK.
Grey seals have a varied diet, feeding mostly on fish, and occasionally on invertebrates such as octopuses and lobsters. Their main predators are orcas, and they are also prey to sharks. The pups are preyed upon by eagles and gulls. The type specimen of H. g. grypus (Zoological Museum of Copenhagen specimen ZMUC M11-1525, caught in 1788 off the island of Amager, Danish part of the Baltic Sea) was believed lost for many years, but was rediscovered in 2016, and a DNA test showed it belonged to a Baltic Sea specimen rather than from Greenland, as had previously been assumed (because it was first described in Otto Fabricius' book on the animals in Greenland: Fauna Groenlandica). The name H. g. grypus was therefore transferred to the Baltic subspecies (replacing H. g. macrorhynchus), and the name H. g. atlantica resurrected for the Atlantic subspecies.
