BioKIDS home

Kids' Inquiry of Diverse Species

American marten

Martes americana

What do they look like?

American martens measure 320 to 450 mm, with the tail adding 135 to 230 mm more. These animals weigh between 280 and 1,300 g. Females are slightly smaller and lighter than males.

A marten's fur is long and shiny. The head is gray, legs and tail are very dark brown or black, the chest has a cream colored patch, and the back is light brown.

American martens are long, slender animals. The eyes are large, the ears are cat-like, and the claws are sharp and curved.

  • Sexual Dimorphism
  • male larger
  • Range mass
    280 to 1,300 g
    9.87 to oz
  • Range length
    320 to 450 mm
    12.60 to 17.72 in
  • Average basal metabolic rate
    3.579 W

Where do they live?

American martens, Martes americana, are found in the northern parts of North America. Martens are found from Newfoundland and Nova Scotia to Alaska. They are found sporadically in parts of California and in northern states, although loss of forests in these areas have reduced populations of martens since Colonial times.

What kind of habitat do they need?

American martens are found primarily in mature, northern forests dominated by pines, firs, spruce, birch, and aspen. They like mature forests, which can provide hollow trees, crevices, or vacant ground burrows in which they can make their homes.

How do they reproduce?

One male may mate with many females during a year. When females are ready to breed, they alert males by making scent markings in their territories. Before mating, a pair will wrestle and play together.

Breeding season is in June and August, but American martens have a strange kind of pregnancy. The growing baby martens do not develop right away. They spend about 200 days in a kind of suspended animation before they connect to the uterus of the mother. After this happens, the embryos develop for only 28 days. The 1 to 5 blind young (kits) are born in late March or early April in dens lined with dried plant material.

The young martens grow quickly. Their eyes open by the age of 39 days, and they only drink their mother's milk until they are 42 days old. They are as big as their parents by 3.5 months, although they cannot breed themselved until they are 15 to 24 months of age.

  • How often does reproduction occur?
    Females may breed four times in a season at 6-17 day intervals. Breeding season occurs once per year.
  • Breeding season
    Breeding season is in June to August.
  • Range number of offspring
    1 to 5
  • Average number of offspring
  • Average number of offspring
  • Range gestation period
    220 to 275 days
  • Average weaning age
    42 days
  • Range age at sexual or reproductive maturity (female)
    15 to 24 months
  • Range age at sexual or reproductive maturity (male)
    15 to 24 months

Not much is known about the parental behavior of these animals. Because they are mammals, we know that the female provides her young with milk and with a home for the first part of their lives. It is not clear how much males interact with their offspring.

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

How long do they live?

American martens can live for up to 17 years in captivity. Although martens in the wild probably do not live as long as those in captivity, wild females are still able to breed at the age of 12 years.

How do they behave?

Martes americana is usually solitary and nocturnal. On occasions they have been observed in male/female pairs, and they have also been seen with dependent young.

American martens are somewhat arboreal (tree dwelling) and move with great ease in trees. They mark scent trails from tree to tree with their strong scent glands. In spite of this, they are reported to do most of their hunting on the ground. Most hunting occurs at dusk and dawn, when prey species are most active. In addition, these animals are accomplished swimmers and can even swim under water.

Home range sizes vary considerably with habitat and prey densities. Population densities of 1.7 martens per square km are common in good habitat, but drop to 0.4 martens per square km in poor habitat. Martes americana does not hibernate and is active all winter.

American martens are most active at night. They hunt most at dawn and dusk when prey animals are most active. Males and females are sometimes seen together, but they prefer to spend their time alone.

American martens spend a lot of their time in the trees, but they do most of their hunting on the ground. They mark scent trails from tree to tree with their strong scent glands. They also swim and dive well.

Home range sizes vary considerably with habitat and prey densities. American martens do not hibernate and is active all winter.

  • Average territory size
    2.3 to 8.1 km^2

Home Range

Home ranges of 8.1 square km for males and 2.3 square km for females are reported.

How do they communicate with each other?

American martens have complex means of communication. In addition to the scent marking so common in Mustelidae, they use vocalizations (huffs, chuckles, and screams). Physical contact is important between mates as well as between mothers and their offspring. The role of visual cues in communication has not been reported, but in many Mustelids, body postures play an important role in communication. It is likely that these animals are similar to other members of their family in this respect.

What do they eat?

American martens eat mostly meat. They are willing to eat any animal they can catch. Most of the time, they catch squirrels and micebut can sometimes eat birds, fruit, nuts, insects, and carrion.

American martens kill their prey with a quick, powerful bite to the back of the prey animal's neck. They sometimes have fast-paced chases in trees with red squirrels.

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • eggs
  • carrion
  • insects
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

What eats them and how do they avoid being eaten?

Predators have not been reported for American martens. However, it is likely that young martens may be vulnerable to large carnivores like wolves or owls.

What roles do they have in the ecosystem?

As predators, American martens may have significant impact on prey populations, helping to structure the forest community.

Do they cause problems?

This species could possibly be considered a pest, in that it reduces the population of game species such as squirrels and rabbits. However, they live in areas that are usually sparsely populated by humans and are not likely to impacts humans.

How do they interact with us?

Marten pelts are very valuable and are taken in controlled hunts.

  • Ways that people benefit from these animals:
  • body parts are source of valuable material

Are they endangered?

Collection of pelts has reduced populations in many parts of the species range. The destruction of coniferous forest habitat has also led to decreased numbers. In spite of these threats, American martens are not considered endangered.


Nancy Shefferly (editor), Animal Diversity Web.

Eric J. Ellis (author), University of Michigan-Ann Arbor.


Buskirk, Steven W., Alton S. Harestad, Martin G. Raphael, and Roger A Powell [Editors]. 1994. Martens, Sables, and Fishers. Biology and Conservation. Cornell University Press.

Macdonald, Dr. David. 1984. The Encyclopedia of Mammals. Equinox (Oxford) Ltd. Pgs 118-119.

Nowak, Ronald M. 1991. Walker's Mammals of the World, 5th Edition. The Johns Hopkins University Press. Pg 1117.

Parker, Sybil P. [Editor]. 1990. Grzimek's Encyclopedia of Mammals, Vol. 5. McGraw-Hill Publishing Company. pgs 413-414.

Ulrich, Tom J. 1990. Mammals of the Northern Rockies. Mountain Press Publishing Company, Missoula. Pg 84.

Clark, T. 1999. American marten| Martes americana . Pp. 165-166 in D Wilson, S Ruff, eds. The Smithsonian Book of North American Mammals. Washington D.C.: The Smithsonian Institution Press in Association with the American Society of Mammologists.

University of Michigan Museum of ZoologyNational Science Foundation

BioKIDS home  |  Questions?  |  Animal Diversity Web  |  Cybertracker Tools

Ellis, E. 1999. "Martes americana" (On-line), Animal Diversity Web. Accessed May 19, 2024 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
Copyright © 2002-2024, The Regents of the University of Michigan. All rights reserved.

University of Michigan