If you ever snowshoe or cross-country ski in Colorado’s high mountain forests, you are likely to see an American marten. The American marten, often called a pine marten, is a medium-sized member of the mustelid family. It is closely related to fishers, badgers, skunks, wolverines and weasels. All mustelids have scent glands under their tails. The American marten also has scent glands on its belly.
During winter, American martens have thick, dark brown fur and an orange throat patch. Their summer coat is lighter in color and texture. They are 21 to 26 inches in length, including the long, bushy tail and weigh one and a half to three pounds. Males are larger than females. They are active throughout the year and are well-adapted for life in a cold and snowy environment. Martens have broad feet with fur-covered soles that act as snowshoes and enable them to travel on top of deep snow.
Martens are perfectly at home in the dense cover of lodgepole pine, Douglas fir, and spruce. These forests provide prey, protection, den and rest sites. Martens are strong and agile climbers. They use their long tails as rudders as they scurry across tree branches. They use sharp, semi-retractable claws to jump from branch to branch pursuing prey or to run down trees head first like a squirrel.
Although martens spend a lot of their time in the trees, they do most of their hunting on the ground. They prefer red-backed voles and red squirrels, but will gobble almost any small rodent, as well as rabbits, reptiles, and birds. They also eat carrion, insects, earthworms, eggs, berries, conifer seeds, and honey.
Most hunting occurs at dusk and dawn, when prey species are most active. Martens investigate every crevice, log, or stump in search of food. They sometimes stalk their prey and pounce on the unwary victim from about. In winter, they will hunt below the surface of the snow for small animals that have taken refuge in downed trees. Martens are excellent swimmers and will even swim in pursuit of a meal.
Martens are solitary and territorial. Both sexes mark scent posts and travel routes on trees by dragging the scent glands on their abdomens over logs and branches. If two martens meet, they bare their teeth and snarl. They huff, pant, chuckle, growl, scream, whine, and eep. The “loser” of the encounter leaves.
During cold weather, martens have a hard time keeping warm, so they tunnel deep under the snow into tangles of tree roots for warmth. They den in hollow trees, crevices, or vacant ground burrows.
Martens give birth to their young in March and April. Like most other mustelids, martens experience delayed implantation. 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. This delay is important because it allows the young to be born during the early spring when there is more food and warmer weather. American martens usually have litters of two to five young.