Muskrats are semi-aquatic mammals that inhabit areas abundant in water like wetlands, ponds, lakes and marshes. For shelter, muskrats will either dig tunnels or construct lodges, depending on the immediate habitat. In areas with steep banks or dams, muskrats will dig tunnels that begin underwater and lead up above the water level, where the chamber can remain dry.
In other areas without steep walls or dams, muskrats build dome-shaped lodges out of nearby vegetation and mud. What Does a Muskrat Look Like? How to Identify a Muskrat Muskrats are semi-aquatic and live near waterways, building their dens along the banks. Denning and Feeding Habits Due to their need for ready access to bodies of water, muskrats are usually found in wetlands, swamps, and coastal areas with abundant vegetation. Problems Caused by Muskrats Their denning and feeding habitats are the main causes of conflict between muskrats and humans.
Quicklinks Muskrat vs. Nutria Muskrat vs. This ability is greatly facilitated by the buoyant qualities of the thick waterproof fur. When swimming on the surface, the muskrat tucks its front feet slightly forward against the upper chest while using the back feet in alternate strokes to propel the body. The tail is used at most as a rudder. When the muskrat is swimming under water, however, the sculling action of the tail probably provides as much propulsive force as do the hind feet.
In the late evening during ice-free periods of the year, muskrats can be seen swimming, sitting at feeding stations such as logs or points of land, and busily improving lodges. Although the muskrat builds lodges near the water and is an accomplished swimmer, it is not a close relative of the beaver, as is sometimes thought.
Nor is it a true rat. Instead, it is basically a large field mouse that has adapted to life in and around water. Unique characteristics The muskrat, together with the beaver and several other mammals, is capable of remaining submerged up to 15 minutes if in a relaxed state. Non-aquatic mammals cannot do this because they need a constant supply of oxygen and must continually expel carbon dioxide. The muskrat is able to partially overcome this problem by reducing its heart rate and relaxing its muscles when submerged; this reduces the rate at which oxygen is used.
Also, it stores a supply of oxygen in its muscles for use during a dive and is less sensitive to high carbon dioxide levels in the blood than are non-diving mammals. This ability for extended dives is important in escaping enemies, digging channels and burrows, cutting submerged stems and roots, and travelling long distances under the ice.
Non-aquatic mammals such as dogs or humans would have great difficulty in trying to chew on a large object under water, because water would enter the mouth, throat, and nasal passages. This problem has been overcome in the muskrat through the evolution of incisors, or cutting teeth, that protrude ahead of the cheeks and of lips that can close behind the teeth. This adaptation permits the muskrat and the beaver to chew on stems and roots under water "with its mouth closed.
The muskrat is more widely distributed in North America than almost any other mammal and in this respect is a very successful species. It is found from the Arctic Ocean in the north to the Gulf of Mexico in the south and from the Pacific Ocean in the west to the Atlantic Ocean in the east.
Human activities in North America during the last two centuries have not significantly affected the distribution of muskrats. In some cases, however, the draining of marshes or swamps for agricultural or other purposes has completely exterminated local populations. In others, the building of irrigation ditches and canals has increased populations.
Until the early part of this century, muskrats occurred only in North America. In about , they were introduced to Europe, where they quickly established themselves as permanent residents. They spread northward and eastward, and today are common in Europe and northern Asia. Of all plants available in marshes, cattails are most preferred as a food item.
However, muskrats appear to thrive equally well on a diet of bulrushes, horsetails, or pondweeds, the last two constituting the basis of the diet in northern latitudes. They also eat a variety of other plants, including sedges, wild rice, and willows. During the winter a thick layer of ice restricts the muskrat to the interior of the lodge or burrow and the watery environment beneath the ice. It covers considerable distances under the ice searching for food. When the muskrat reaches a feeding area it chews off portions of plants and carries them to the nearest push-up, where it eats.
This foraging activity under perhaps a metre of ice and snow, in ice-cold water and almost total darkness, is truly a remarkable feat. When their normal food items are scarce or unavailable, and food of animal origin is abundant, muskrats are known to be highly carnivorous, or meat-eating.
Under these circumstances muskrats most commonly consume animals such as fish, frogs, and clams. However, muskrats rarely do well on this type of diet and consuming such foods is generally taken to be evidence of hard times.
Mating activity occurs immediately following spring break-up in March, April, or May. Mating pairs do not form lasting family ties; instead, the muskrat appears to be promiscuous, or have many mates.
Males compete fiercely for females. The birth of the litter, containing five to 10 young, occurs less than a month after the female has been mated. The same female normally has another litter a month after the first, and sometimes yet another a month after the second. The young at birth are blind, hairless, and almost completely helpless, but they develop rapidly.
They are covered with thin fur at the end of the first week, their eyes open at the end of the second week, and they normally begin leaving the lodge on short trips at about two to three weeks of age. Breeding continues throughout the summer, with the last litters born about August. Food is plentiful during the summer and the young grow rapidly.
Few rodents live to old age; they are usually killed by other animals while still quite young, or they die accidentally. The limited information available suggests that muskrats become old at three or four years of age. When they reach this age, they lose much of their natural alertness and fall easy prey to mink, foxes, and other predators.
The muskrat is a vicious fighter when provoked. It stands its ground courageously if an escape route to deep water is not available and can inflict considerable damage on an attacker with its long incisors, or cutting teeth.
In spite of this, it is often preyed upon by other species. The mink occupies much of the same habitat as muskrats and can be the cause of heavy mortality among juveniles under certain conditions. Mink use the same burrow systems, dig into muskrat lodges, and may enter lodges through plunge holes.
The snapping turtle and the northern pike also inhabit marshes and prey on the muskrat. When muskrats wander on dry land in search of new habitat, they are subject to predation by members of the dog family—wolves, coyotes, foxes, and domestic dogs—as well as by typical predators such as badgers, wolverines, fishers, racoons, and lynx. The muskrat has long been hunted by humans, probably the major enemy or predator of this species.
Prior to the colonization of North America by Europeans, it was hunted occasionally for food. With the coming of the early settlers and the introduction of guns and traps, the muskrat was hunted intensively for its fur. This activity has persisted to the present day—muskrat fur is still in demand. Also, the muskrat is still used as food by people in some parts of North America. Muskrats, like many other wildlife species, show large fluctuations in numbers that follow what appears to be a regular pattern.
In the case of the muskrat, numbers decrease drastically about every seven to 10 years. At such times, few or no muskrats can be found where two or three years earlier there had been thousands. These catastrophes are often blamed on predators or on over-trapping. However, scientists do not believe that these are the real causes.
Instead, for some as-yet-unknown reason, the health of individuals deteriorates, causing widespread death and reproductive failure. Reproductive and death rates return to normal one or two years following such a population decline, leading to an increase in muskrat numbers once more. The muskrat contributes more to the total combined income of North American trappers than any other mammal.
Because of its important role in the trapping industry, it has been studied extensively. The first major studies were conducted by the Canadian Wildlife Service on the Mackenzie River Delta in the far north and the Athabasca—Peace Delta in northern Alberta during the late s.
A thorough understanding of habitat requirements, food habits, reproduction, longevity, causes of mortality, long-term changes in numbers, and the effect of weather on all these factors is essential to put management procedures on a sound scientific basis. More recent studies in eastern Canada and central and eastern United States have augmented what is now a comprehensive body of knowledge on the dynamics and management of muskrat populations.
There are two major methods of managing muskrat populations: the first is to improve habitat, and the second is to regulate the commercial harvest by trappers. The most common method of improving habitat is to regulate water levels between about 1 and 2 m of depth over large areas by building dams at strategic points in lake outlets and streams.
Sometimes this occurs as a natural side effect of beaver dams. Regulation of commercial harvest is based on current population sizes and future population trends. Usually the harvest is maintained at the highest possible level that will not adversely affect population sizes and harvests in future years. The future of the muskrat in Canada is bright. In spite of heavy trapping pressure, the draining of marshes for agricultural purposes, and unprecedented industrial activity, the species has never been endangered in Canada.
Indeed, population numbers today are probably almost as high as they were a thousand years ago. Boutin, S. Novak, J. Baker, M. Obbard, and B. Malloch, editors. Wild furbearer management and conservation in North America. Ontario Ministry of Natural Resources, Toronto.
Parker, G. Characteristics of a population of muskrats Ondatra zibethicus in New Brunswick. Canadian Field-Naturalist 1—8. Perry, H. Muskrats Ondatra zibethicus and Neofiber alleni. Chapman, and G. Feldhamer, editors. Wild mammals of North America. Johns Hopkins University Press, Baltimore. Proulx, G. The ecology of the muskrat Ondatra zibethicus at Luther Marsh, Ontario. Canadian Field-Naturalist — All rights reserved. Aleksiuk Revision: G. Parker, Photo: Corel Photo Studio.
The Northern Leopard Frog Lithobates pipiens is named for its leopard-like spots across its back and sides. Historically, these frogs were harvested for food frog legs and are still used today for dissection practice in biology class.
Mostly though, they tend to prefer vegetation like cattails, waterlilies, roots and pondweed. They also eat snails, mussels, salamanders, crustaceans, fish and young birds.
These small animals are very big eaters. Muskrats eat one-third of their weight every day, according to the ADW. Though they need a large supply of food, muskrats usually don't travel any farther than feet 46 meters away from their homes.
Muskrats make their nests on tree stumps sticking out of 15 to 40 inches 38 to cm of water using vegetation. Females have a gestation period of three to four weeks and give birth to three to eight young, according to Encyclopedia Britannica. They can have up to three litters each year. Baby muskrats are called kits. At 30 days old, kits can swim, dive and feed themselves. Kits are fully grown at six weeks and typically stay with their family, unless there is overcrowding.
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