Which ocean animal is famous for using rocks to open shellfish?

The sea otter is famous for using rocks to open shellfish. It may place a stone on its chest and repeatedly smash a clam, mussel, or other hard-shelled prey against it while floating on its back.

Sea otters have exceptionally dense fur rather than a thick layer of blubber. Their fur traps air and helps insulate them in cold Pacific waters, but it must be kept clean and water-repellent. Grooming therefore takes a large part of an otter’s daily routine.

Sea otters are important predators of sea urchins. By reducing urchin numbers, they can help kelp forests survive, making them a classic example of a keystone species. They also use their forepaws to handle food, and some individuals carry a favorite stone in a loose fold of skin beneath the forearm.