The American marten, or pine marten, is a medium-sized member of the weasel family (the mustelids). It is also known as the American sable, and is closely related to fishers, badgers and weasels. Martens were trapped widely in the 1800’s for it’s rich brown fur, and is still trapped in some states for its beautiful coat. In color, the fur is a rich, medium brown with a characteristic orange throat patch.
Pine martens are 21 to 26 inches in length, including the long, bushy tail and weigh 1.5 to 2.75 pounds. Males are 20 to 40% larger than females. Being carnivorous, they feed on primarily on voles, mice, red squirrels, with supplemental feeding on insects, birds, eggs, fruit and nuts. They may live for up to 17 years.
Tracks of the pine marten reveal five toes in a plantigrade foot averaging 1.5 to 2.5 inches in with by 3 to 4 inches in length. The straddle is 3 to 4.5 inches and the stride of a marten averages around 20 inches, with the 2 X 2 bounding pattern typical of the weasel family.
The breeding season for martens is in late March and April. Like most other mustelids, fishers experience delayed implantation of 10 – 11 months. The egg is fertilized at the time of mating, then the embryo stops developing and remains in a dormant state until the female is in good physical condition during late winter, the embryo then implants and develops. The actual gestation lasts approximately 27 days with parturition (birth) occurring in March and April. A typical litter has 2 to 4 kits, with one litter per year. They typically breed again within 10 days of parturition. Females breed at one year and have their first litter of about 3 kits at age 2 years. Males are probably not sexually mature until age 2. Martens are pretty solitary animals except during the breeding season when plantar glands on their hind feet increase secretions and a black, tarry substance of unknown origin signal their intent to mate.
Martens are similar in behavior to their larger cousin the fisher. Martens prefer late successional forests, with mature to old growth trees being especially important for natal and maternal den sites. Martens appear to like to make temporary dens and perches in mistletoe bundles known as ‘witches brooms’. They are distributed circumboreally, found through spruce-fir forests from northern New Mexico to the northern limit of trees in Alaska, and from the West Coast to the Newfoundland Islands, in mountain ranges with suitable habitat. Marten generally require a high canopy cover (up to 70%), although Wild Things researchers have documented marten presence in forests recovering from recent fires. This is due to the high numbers of mice and voles that feed on the rich vegetation that thrives after a burn.
The home range is probably half to one square mile, but ranging up to seven miles. Males have larger home ranges than females, with females often having overlapping territories, but rarely overlapping with males.
Martens are highly inquisitive, and are known for their habit of investigating anything new in their territories. Unfortunately, this makes martens very easy to trap. They are often encountered in the Yellowstone Ecosystem feeding on the carcass of a winter-killed elk or other ungulate.