The island is one of the best places in Gwynedd to see grey seals. In mid summer over 200 can be seen, lying in the sun on the rocks or swimming in the sea. About 15 pups are born each autumn. Their sharp teeth and strong jaws are perfect for breaking the shells of lobsters and crabs which live in the waters. It is also possible to see bottlenose and Risso's dolphins, and porpoises. The currents around the island carry food-rich water. The Whale and Dolphin Conservation Society has been carrying out surveys since 1999 to find out which areas are important for feeding and nursing calves.