The British Isles are home to two species of the Pinnipedia order, and both are members of the Phocidae (or earless seal) family. They occupy an almost unique place in the human psyche; we may be astounded by whales, impressed by dolphins, excited by badgers and childlike about rabbits, but there seems to be genuine affection for the blubbery pinnipeds. They have become perfectly adapted to the marine environment at the expense of mobility on land. Their bodies are a wonderfully-streamlined torpedo shape, the hindlimbs are short to act as rudders, and the forelimbs have become perfect flippers for swimming with. Skin between the digits of hands and feet is stretched to make swimming more efficient. These adaptions have made movement on land difficult, however. The short hindlimbs do not give much traction, and the forelimbs are unable to move forward far enough to properly support the body. It is little surprise that they spend most of their lives in the water, even sleeping in it!
Seals have, however, often had a fraught relationship with fishermen, with whom they have to compete for food sources. They are often caught in nets (one study in the year 2000 suggesting that the Cornish grey seal was dying in monkfish nets more quickly than it could reproduce) and, though it may be hard to believe, occasional culls were only stopped in 1983 in response to public outcry. It is legal to kill a seal if it is found near a fishery.
Common or Harbour seal Phoca vitulina
The common seal is not an endangered species and is believed to be the most widespread of all pinnipeds. It is found around most of the north and east of the country from East Anglia and the Wash right around the Scottish Islands to Northern Ireland – and occasionally turns up in larger estuaries, even being recorded in the Thames every now and then.
It spends most of its time in the shallows and is at its most active in the daytime, making the common seal's regular appearances around human habitations popular events. In June and July, it forms breeding colonies. Although common seals are believed to be monogamous, it seems that they are not territorial and there is no particular social structure. While the colony rests, the bulls will take turns to keep a look-out for predators.
Grey or Atlantic seal Halichoerus grypus
This species is rather different in behaviour to its common cousin. It is endangered, and it has been estimated that the British Isles are the breeding ground for around two-thirds of the world's population. It can be found anywhere from the south Devon coast, through Cornwall, the Scillies, Lundy, south Wales and western Ireland and as far round the Scottish coast as the Orkneys and Hebrides. Their activity is variable depending on factors such as weather and tide, and with no apparent preference for day or night. It is only occasionally found in estuaries, and even then only in those that are free of any pollution.
The grey seal breeds in October and also forms colonies, usually on rocky shores, and in this species a bull will take control of a territory with breeding rights over a number of female 'cows'. Colonies may take over some smaller islands completely, and stray further from the sea than common seals – the highest altitude recorded is a mighty 85 metres!
Other seals have been recorded around the British Isles. All are polar species who have on rare occasions made it to the north of Scotland, and are not considered to be 'native'. They are:
- Harp seal, Phoca groenlandica - has been spotted on ice floes out to sea.
- Ringed seal, Phoca hispida - the world’s smallest seal, usually found off Greenland and in the Baltics.
- Bearded seal, Erignathus barbatus - occurs all around the Arctic Circle and has occasionally been found on Scottish islands.
- Hooded seal, Cystophora cristata - a North American species that very rarely arrives on British coasts.