Grey seal bulls fighting (Halichoerus grypus) in shallow water. Grey seals can be aggressive and fights are usually between bulls over mating rights after the pups have been born. The grey seal gives birth after a gestation of just under a year. A pup is nursed for up to two months before becoming independent. The grey seal lives in large groups in coastal waters in the North Atlantic Ocean. It feeds almost exclusively on fish. Photographed in November, in Lincolnshire, UK.