Sea otters are famous for using tools - specifically using rocks to break open shellfish and other prey. This behavior is rare among non-primate animals in the wild. Sea otters float on their backs, place rocks on their chests, and smash shellfish against them to access the meat inside. The other options are incorrect: sea otters don't swim entire oceans, they're adapted to cold coastal waters (not any climate), and while they can come ashore, they're primarily marine mammals.