The Arctic Shrew, Sorex arcticus, is a medium-sized shrew found in Canada and the northern United States. Separate species status has been proposed for the Maritime Shrew , Sorex maritimensis, which is found in New Brunswick and Nova Scotia and has been considered to be a subspecies of the Arctic Shrew. The Tundra Shrew, Sorex tundrensis, was formerly considered to be a subspecies of the Arctic Shrew.

It is dark brown or black on its back, lighter brown on its flanks and lighter underneath. The fur is greyer in winter. Its body is about 11 cm in length including a 4 cm long tail and it weighs about 10 g.

These animals are found in wetlands, especially swamps, or open areas near wetlands. Adults are territorial.

They eat insects, worms and small invertebrates. Predators include hawks and owls.

These animals are active day and night year-round. They are generally solitary except during mating in spring. The female has one litter of 5 to 9 young in a nest made by the female. Males may mate with more than one female.