Muskrat
Muskrat
The muskrat or musquash (Ondatra zibethicus ) is a relatively large, amphibious rodent classified in the family Muridae that is native to North America. The northern range of the muskrat reaches as far as the limits of the boreal forest from Alaska to Labrador and Newfoundland. The southern range of the muskrat extends through much of the United States as far south as northern Baja California, although not in the coastal plains of the southern states or coastal California. Muskrats have also been introduced in Europe, where it was hoped they would become a valuable source of fur.
Biology of Muskrats
Muskrats can reach a body length of 12.6 in (32 cm), plus a long tail 11.8 in (30 cm) and a weight of about 3.3 lb (1.5 kg), although most animals are typically about 2.4 lb (1.1 kg) in weight. The waterproof fur (pelage) of muskrats is composed of a dense under-fur, important for insulation, and a lager of longer, usually dark-brown, protective guard hairs.
Muskrats of both sexes have a pair of large glands near their anus, which enlarge during the breeding season, and produce a strongly scented chemical called musk, from which the common name of these animals is derived. Musk is used in the manufacture of perfumes, although it is not commonly harvested from muskrats for this purpose.
Muskrats are excellent swimmers, using their partially webbed feet which are fringed with stiff hairs that broaden the propulsive surface. The hairless, scaly tail is flattened, and is used as a rudder during swimming. Muskrats can remain submerged for as long as seventeen minutes, and they often do this to hide, when they feel threatened by a predator.
Muskrats mostly eat aquatic and riparian plants of various sorts, and they sometimes forage on land, occasionally in farmers’ fields. Muskrats also eat mussels, fish, and other aquatic animals. Most feeding is done at night, dawn, or dusk, but muskrats are sometimes seen during the day.
Muskrats are found in marshes, swamps, and other types of static, open-water wetlands, where they build family houses made of mounds of piled-up reeds and cattails plastered with mud. These structures are typically more than one meter high and several meters broad. Into these mounds the muskrats construct a tunnel with an underwater access hole, leading to an internal den with a grassy bed. Muskrats also live along streams and rivers, where their dens are dug into earthen banks above the high-water level, with the access hole located under low-water and below the limit of freezing in winter. Muskrat houses and diggings are often destroyed during spring floods, and are not usually repaired; the muskrat will instead construct a new accommodation.
In optimal habitats such as reedy marshes, muskrat population densities can reach 85 animals per hectare. Sometimes, excessively large muskrat populations can degrade the local habitat, forcing a population crash until the vegetation recovers.
Muskrats are very fecund, and can produce several litters each year. They live in family units in mud lodges in territories, which they actively defend from incursions by other muskrats. During the spring, dominant females take possession of the best habitat and drive away younger females and males. Much strife occurs at this time, and some animals are killed during the fighting, and those that are driven away are often killed by predators.
Economic Importance
Muskrats are widely trapped for their durable fur, which is prized for the manufacture of warm, fashionable coats and other garments. Where muskrats are abundant, trapping can have a significant economic impact, providing important employment for people living in rural environments. Millions of muskrats are trapped each year, and muskrats are one of the economically most important wild fur-bearing animals in North America. The best furs are obtained during winter, when the pelts are in prime condition. Some rural people also eat muskrats.
Muskrats are sometimes considered to be important pests, especially when they burrow into earthen dams, dikes, irrigation channels, and other structures. The burrows of muskrats weaken these constructed works, and can cause them to fail or erode. Muskrats are also regarded as pests in parts of their introduced range in Europe, where they are not well controlled by natural predators or disease.
The muskrat was introduced to Europe by Prince Colloredo-Mannsfield, who released five individuals in a pond on his estate near Prague, now in the Czech Republic, following a hunting expedition to Alaska. It is likely that all of the millions of muskrats in Europe and northern Asia are the descendants of these animals, which are actively controlled to decrease the damage they cause.
Resources
BOOKS
MacDonald, David, and Sasha Norris, eds. Encyclopedia of Mammals. New York: Facts on File, 2001.
KEY TERMS
Musk —A strong-smelling secretion of the glands of some animals, generally associated with breeding and the marking of territories. Musk is produced by certain species of deer, cats, otter, the muskrat, and other animals. Musk is used to manufacture perfumes. Much of the modern usage involves synthesized musk.
Nowak, Ronald M. Walker’s Mammals of the World. 6th ed. Baltimore: The Johns Hopkins University Press, 1999.
Wilson, D. E. and D. Reeder. Mammal Species of the World. 3rd ed. Washington, DC: Smithsonian Institution Press, 2005.
Bill Freedman
Muskrat
Muskrat
The muskrat or musquash (Ondatra zibethicus) is a relatively large, amphibious rodent that is native to North America . The northern range of the muskrat reaches as far as the limits of the boreal forest from Alaska to Labrador and Newfoundland. The southern range of the muskrat extends through much of the United States as far south as northern Baja California, although not in the coastal plains of the southern states or coastal California. Muskrats have also been introduced in Europe , where it was hoped they would become a valuable source of fur.
Biology of muskrats
Muskrats can reach a body length of 12.6 in (32 cm), plus a long tail 11.8 in (30 cm) and a weight of about 3.3 lb (1.5 kg), although most animals are typically about 2.4 lb (1.1 kg) in weight. The waterproof fur (pelage) of muskrats is composed of a dense underfur, important for insulation, and a lager of longer, usually dark-brown, protective guard hairs.
Muskrats of both sexes have a pair of large glands near their anus, which enlarge during the breeding season, and produce a strongly scented chemical called musk, from which the common name of these animals is derived. Musk is used in the manufacture of perfumes, although it is not commonly harvested from muskrats for this purpose.
Muskrats are excellent swimmers, using their partially webbed feet which are fringed with stiff hairs that broaden the propulsive surface. The hairless, scaly tail is flattened, and is used as a rudder during swimming. Muskrats can remain submerged for as long as seventeen minutes, and they often do this to hide, when they feel threatened by a predator .
Muskrats mostly eat aquatic and riparian plants of various sorts, and they sometimes forage on land, occasionally in farmers' fields. Muskrats also eat mussels, fish , and other aquatic animals. Most feeding is done at night, dawn, or dusk, but muskrats are sometimes seen during the day.
Muskrats are found in marshes, swamps, and other types of static, open-water wetlands , where they build family houses made of mounds of piled-up reeds and cattails plastered with mud. These structures are typically more than one meter high and several meters broad. Into these mounds the muskrats construct a tunnel with an underwater access hole, leading to an internal den with a grassy bed. Muskrats also live along streams and rivers , where their dens are dug into earthen banks above the high-water level, with the access hole located under low-water and below the limit of freezing in winter. Muskrat houses and diggings are often destroyed during spring floods, and are not usually repaired; the muskrat will instead construct a new accommodation.
In optimal habitats such as reedy marshes, muskrat population densities can reach 85 animals per hectare. Sometimes, excessively large muskrat populations can degrade the local habitat , forcing a population crash until the vegetation recovers.
Muskrats are very fecund, and can produce several litters each year. They live in family units in mud lodges in territories, which they actively defend from incursions by other muskrats. During the spring, dominant females take possession of the best habitat and drive away younger females and males. Much strife occurs at this time, and some animals are killed during the fighting, and those that are driven away are often killed by predators.
Economic importance
Muskrats are widely trapped for their durable fur, which is prized for the manufacture of warm, fashionable coats and other garments. Where muskrats are abundant, trapping can have a significant economic impact, providing important employment for people living in rural environments. Millions of muskrats are trapped each year, and muskrats are one of the economically most important wild fur-bearing animals in North America. The best furs are obtained during winter, when the pelts are in prime condition. Some rural people also eat muskrats.
Muskrats are sometimes considered to be important pests , especially when they burrow into earthen dams , dikes, irrigation channels, and other structures. The burrows of muskrats weaken these constructed works, and can cause them to fail or erode. Muskrats are also regarded as pests in parts of their introduced range in Europe, where they are not well controlled by natural predators or disease .
The muskrat was introduced to Europe by Prince Colloredo-Mannsfield, who released five individuals in a pond on his estate near Prague, now in the Czech Republic, following a hunting expedition to Alaska. It is likely that all of the millions of muskrats in Europe and northern Asia are the descendants of these animals, which are actively controlled to decrease the damage they cause.
Bill Freedman
KEY TERMS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- Musk
—A strong-smelling secretion of the glands of some animals, generally associated with breeding and the marking of territories. Musk is produced by certain species of deer, cats, otter, the muskrat, and other animals. Musk is used to manufacture perfumes. Much of the modern usage involves synthesized musk.