American martens, Martes americana, are found in the northern reaches of North America. The species is present from Newfoundland and Nova Scotia west to Alaska and south into sections of the rocky mountain range and California. Martens are found sporadically in parts of New York state, Michigan, Minnesota, Maine, and Wisconsin. Although populations were greater in the southeastern portion of the species range in Colonial times, loss of forest habitat in these areas has restricted their range. Programs for reintroduction of these animals in Minnesota and Ontario may help populations to recover.
Martes americana is found primarily in mature, northern forests. These animals are closely associated with lodgepole pine, Douglas fir, spruce, and mixed harwood forests. They tend to be found in structurally complex, mature forests, and can occur at all elevations where such habitat exists. They den in hollow trees, crevices, or vacant ground burrows.
Male American martens measure 360 to 450 mm, with the tail adding 150 to 230 mm more. Weights of males range between 470 and 1,300 g. Females are slightly smaller and lighter, with head-body lengths between 320 and 400 mm, and tails measuring 135 to 200 mm. Females weigh betweeen 280 and 850 g.
The 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. Eyes are large and ears are cat-like. Claws are sharp and curved.
Mating has been described as polygynous. During estrus, females use scent marks to advertize their sexual condition. Courtship between males and females can be quite protracted, and involves tumbling, playing and wrestling. In captivity, females reportedly exhibit between 1 and 4 periods of sexual receptivity, each of which lasts from 1 to 4 days. These occur at 6 to 17 day intervals throughout the breeding season.
The breeding season occurs from June to August. Implantation of the fertilized eggs is delayed, and does not take place until February. Although the total period of pregancy is between 220 and 275 days, after implantation in the uterine lining, 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 grow quickly. Eyes open by the age of 39 days. Young martens are weaned after 42 days. Full size is reached very quickly, around 3.5 months after birth. Sexual maturity is reached at 15 to 24 months of age.
Information on the parental behavior of these animals is not readily available. However, as mammals, we know that the female nurses her offspring and provides them with protection and a home for the first part of their lives. Even though the role of males in parental care is not clear,adult males and females have been seen together with immature animals, presumably their offspring. Although American martens are larely solitary, it is still possible that males have some association with their offspring during rearing.
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.
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.
Home ranges of 8.1 square km for males and 2.3 square km for females are reported.
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.
Martes americana is an opportunistic feeder. The diet consists primarily of small mammals, including squirrels and rodents. Occasionally birds, fruit, nuts, insects, and carrion are eaten as well. American martens usually kill their prey with a quick, powerful bite to the back of the prey animal's neck. American martens sometimes have fast-paced chases in trees with a favorite prey item, red squirrels.
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.
As predators, American martens may have significant impact on prey populations, helping to structure the forest community.
Marten pelts are very valuable and are taken in controlled hunts.
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.
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.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
Referring to an animal that lives in trees; tree-climbing.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
flesh of dead animals.
uses smells or other chemicals to communicate
active at dawn and dusk
in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
having more than one female as a mate at one time
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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