According to article on wikipedia ;
Star-nose mole lives in wet lowland areas and eats small invertebrates, aquatic insects, worms and molluscs. It is a good swimmer and can forage along the bottoms of streams and ponds. Like other moles, this animal digs shallow surface tunnels for foraging; often, these tunnels exit underwater. It is active day and night and remains active in winter, when it has been observed tunnelling through the snow and swimming in ice-covered streams. Little is known about the social behavior of the species, but it is suspected that it is colonial.