Martens are larger, heavier-bodied animals than weasels, with thick fur and bushy tails. Members of most species are brown above and light-colored below. The American marten, Martes americana, also called American pine marten and American, or Hudson Bay, sable, is from 20 to 25 in. (51–64 cm) long, including the 7- to 8-in. (18- to 20-cm) tail, and has yellow-brown fur. It lives in coniferous forests from Alaska to the extreme N United States, extending south in western mountain ranges. It is mostly nocturnal and spends much of the time in trees, where it leaps from branch to branch, although it also forages on the ground it makes its den in a hollow tree or log. Its diet consists chiefly of small animals, especially red squirrels (Tamiasciurus), but it also eats berries and nuts.