Suited to the sea: seal natural history

Seals are intelligent, warm-blooded creatures that spend most of their lives at sea, coming ashore only to bask, breed and moult. Seals may look slow and clumsy on land, but in the vast ocean they are swift and graceful swimmers. Their streamlined bodies slice through the water with ease as they catch fish. Their thick layer of fat (blubber) and a covering of dense fur ensures they keep warm in the cold sea.

Seal are well adapted to life at sea and their flippers are perfectly shaped to propel and steer. When you see a seal 'flying' through the water, it becomes clear why the group of animals to which the seal belongs are known as ‘pinnipeds’, which means winged feet.

Seals breathe air, but can dive for up to an hour, reaching depths of up to 500m. They carry three times as much oxygen in their blood as a similarly sized land mammal.

Seals are formidable hunters, perfectly adapted to their marine environment. Their large eyes ensure superb vision under water, even in poor light.

Acute hearing allows them to pinpoint prey and their ears have adapted to allow them to hear well under water. Sensitive whiskers detect vibrations of moving prey in the water, so that even blind seals have been known to survive in the wild. When diving, a seal shuts its nostrils, and strong throat muscles prevent water from entering their wind- pipe, this allows them to feed underwater.

Among seals' favourite foods are sand eels, cod and smiths. Both grey and common seals eat a variety of prey including shellfish, squid and octopus. Their diet is determined by the availability of prey species in any given area. During mating and pepping seasons, grey seal bulls and cows do not feed, losing up to 25% of their body weight.

What is the difference between a grey and a common seal?

Grey and common seals can be difficult to tell apart, especially in the water. Grey seals are much bigger than common and are Britain's largest carnivore.

Grey seal characteristics

‘Roman nose' parallel nostrils

Male = 3m Female = 1.8m

Male = 220g Female = 15Okg

Colouring:' grey with blotches of black & darker grey

Pups born Sept - Nov. Birth weight = 14kg.

Pup's coat = white & silky. Dependent on mother, staying on shore till weaning. Suckles for 4 weeds. Weight at weaning = 45kg.

Lifespan up to 45 years