The Marten (often called the pine marten or American marten) is a weasel that lives in trees. Males are about two feet long, with an eight-inch tail, and they weigh about 1 1/2 pounds. Females are 10 to 20 percent smaller than the males and weigh only half as much as the male. Martens are brown, right to the tip of the tail, and a pale yellowish-brown beneath. Martens are mostly nocturnal, but when they are hungry they are active day or night. Like other weasels, martens are active year-round. In the coldest weather, they may den in a tree hole or a Chickaree nest. Martens are tolerant of humans and easily adapt to feeding areas. In the old days, a marten was the resident mouser in many a miner’s cabins.
Martens are mammals of coniferous forests in northern and western North America.
In Colorado, favored habitats are old-growth sub-alpine forests of spruce, fir or lodgepole pine.
In these forests is where they pursue their preferred food, the chickaree or pine squirrel; as well as nesting birds. On the ground, they also capture red-backed voles.
Mating occurs in the summer, but embryos don’t implant until early spring. One to five young martens are born in April after about a month of gestation. Typical of weasels, the young are blind and nearly naked, but develop rapidly and are weaned at about two months of age. No species habitually preys on martens; trapping and habitat destruction from clear-cutting trees probably are the most important sources of mortality.