Characteristics: The Grey seal is a very large seal, with bulls in the eastern Atlantic populations reaching 2.5–3.3 m (8.2–10.8 ft) long and weighing 170–310 kg (370–680 lb); the cows are much smaller, typically 1.6–2.0 m (5.2–6.6 ft) long and 100–190 kg (220–420 lb) in weight. Individuals from the western Atlantic are often much larger, males reaching 400 kg (880 lb) and females weighing up to 250 kg (550 lb). It is distinguished from the harbor seal by its straight head profile, nostrils set well apart, and fewer spots on its body.

Habitat: In Ireland and the UK, the grey seal breeds in several colonies on and around the coasts. Notably large colonies are at Donna Nook in Lincolnshire, the Farne Islands off the Northumberland Coast (about 6,000 animals), Orkney and North Rona, off the north coast of Scotland, Lambay Island off the coast of Dublin and Ramsey Island off the coast of Pembrokeshire.

Habits: During the winter months grey seals can be seen hauled out on rocks, islands, and shoals not far from shore, occasionally coming ashore to rest. In the spring recently weaned pups and yearlings occasionally strand on beaches after becoming separated from their group.