Minnesota Profile: American Marten (Martes americana)

By Bill Berg, DNR wildlife research biologist

Appearance

The American marten, also known as pine marten and American sable, is characterized by its soft golden brown fur and yellowish bib. Martens are medium-sized predators, weighing 1 to 2 pounds, and measuring 1-1/2 to 2 feet long. Like most other members of the family Mustelidae, the marten has an elongate body and small and rounded ears.

The Tube Family

Besides the marten, the family Mustelidae contains many other "tube-shaped" Minnesota relatives, such as the fisher, mink, otter, long-tailed weasel, short-tailed weasel, and least weasel. Skunks and badgers also belong to this family.

Population Downs and Ups

Marten pelts were a fur-trade mainstay during the 1700s and 1800s, but uncontrolled trapping and extensive logging nearly eliminated martens by the early 1900s. In fact, martens were thought to be absent in Minnesota until about 1950. Even without any reintroductions, the tiny remnant population exploded to the point that regulated trapping began in 1985. Today's population of more than 10,000 martens, spread over much of northern Minnesota, supports a harvest of 2,000 to 3,000 annually, likely more than in any single year of the earlier fur-trade era. Once thought to reside in only mature forests, the marten has surprised biologists by also living in cutovers and northwestern Minnesota prairie edges.

Magnificent Mousers

Small mammals dominate the marten's cuisine. Red-backed voles and deer mice are the favorites, but red squirrels and chipmunks are also eaten. Martens also scavenge deer and moose carcasses, love suet at bird feeders, and sometimes even catch and eat the birds themselves.

Prolonged Pregnancy

Delayed implantation is one of the oddities in the animal world, and most Mustelidae species have it. Marten, despite their small size, are "pregnant" for about 9 months! The females breed in summer, but the many-celled pre-embryonic blastocyst does not implant and begin developing into a fetus until late winter. They give birth to two or three kits in spring.