The grey seal (Halichoerus grypus) is one of the UK's most charismatic marine mammals. The UK hosts approximately 40% of the world's grey seal population, making it one of the most significant global conservation responsibilities for any British wildlife species. Grey seal populations have recovered strongly since protection began in 1914.
Grey seals come ashore to breed in large colonies (rookeries) on remote beaches and islands, primarily in October-December. Pups are born with white coats (lanugo), weaning rapidly over 3 weeks during which mothers fast completely. Pups triple their birth weight during suckling. After weaning, pups moult to adult pelage and disperse — they must learn to hunt entirely independently. Adult males (bulls) can weigh up to 300kg and engage in intense competition for breeding access to females (cows).
Grey seals are generalist predators feeding on fish (including commercially important species like sandeels, gadoids, and flatfish), cephalopods, and crustaceans. They can dive to 300m and remain submerged for up to 30 minutes. Foraging ranges can extend hundreds of kilometres from haul-out sites.
Grey seals are fully protected under the Conservation of Seals Act 1970. Disturbance of breeding colonies causes significant welfare harm — flushed mothers abandon pups, leading to starvation. Key guidance for wildlife watchers: