Also known as Atlantic seals, they may be seen off most of the coasts around Britain, particularly the rocky coasts in the north and west. They breed here from September to December and are protected by law during this time.

Usually they only leave the water to breed or to rest and moult their fur. Grey seals actually vary considerably in colour from black to brown and dull grey to bright silver. The males tend to be darker than the females, although both are usually darker on the dorsal surface than on the underside. Both sexes often have a distinguishing pattern of blotches, allowing individuals to be recognised, but it is usually easier to identify the females. The males on the whole are usually darker than the females, and pale markings around their necks are usually old scars sustained in combat with other males.

Often very vocal, grey seals have been known to snarl, bark, hoot, moan and even hiss. They feed mainly on fish and this can bring them into conflict with fisherman.

For the convenience of observers, who make the vast majority of observations of seals swimming or "bottling" (upright and still in the water, often asleep) in the sea, only those markings on the head and neck are used. Two initial "mug-shots" are taken of every individual (where possible) because the two profiles of the seal bear different sets of markings. Subsequently, every sighting of that seal is logged against its name so that, eventually, we will have gathered at least a partial life history of that individual. Only then can we learn hitherto unknown details of their lives:

In the South-West (Cornwall, Devonshire, the Isles of Scilly and Lundy), the grey seal is found only in a number of widely scattered localities. Nowhere is it found in large numbers, although about 300 may dwell in the local "capital", the Isles of Scilly. There, pups are born on remote and uninhabited islets which can be totally submerged by the heavy seas that run in autumn and winter. This can cause the deaths of some or even all pups that are still being suckled by their mothers. Pups are born yellowy white, orange or creamy white in colouring and finish their weaning period from the 18th day of life onward.

On the mainland and on Lundy, most seals are born on small, tidal beaches at the back of sea caves. These caves are some of the wildest and most beautiful of the few really wild places remaining in southern England. Usually, they have a deep water entrance, and often they run into the cliff for 100 metres or sometimes even more. When storm seas run, then caves are filled with boiling, seething water. It is hard to imagine anything surviving in such places. Nevertheless, they do. Here, for 17 days, it was fed by its very caring mother. The milk it drank was so full of fats that it had the consistency of mayonnaise.