91热爆

These Atlantic grey seals are part of a North Sea population totalling 8,000. Their numbers are greatest here in the Farne Islands in late summer when they come to pup. Like the birds here, they are protected and come to feast on the great abundance of food. They are beautiful swimmers: spindle-shaped with no bits sticking out that would increase drag. They swim with their hind flippers and just use the front ones for steering, or for paddling when they're going very slowly, rather like doggy paddling. Not only are they excellent swimmers, but they're brilliant divers too. They can go down at the drop of a hat to 150 metres, maybe more. There's no way a human diver can match that, whatever gear they wear. If a diver goes too deep for too long and comes up too quickly, he or she gets 'the bends'. Seals avoid this by exhaling before they dive. At depth their lungs collapse with no ill effect. When divers get the bends, the gases in their blood bubble just as they do when you open a fizzy drink. In the seal's world it is we who are the clumsy intruders.