The Muskrat (Ondatra zibethicus)

Sep 26, 2021 Interesting Creatures in Guyana, News

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Kaieteur News – The muskrat (Ondatra zibethicus) is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over a wide range of climates and habitats. It has important effects on the ecology of wetlands, and is a resource of food and fur for humans.
Adult muskrats weigh 0.6–2 kg. (1.3–4.4 lb.), with a body length of 20–35 cm. (8–10 in.). They are covered with short, thick fur of medium to dark brown colour. Their long tails, covered with scales rather than hair, are their main means of propulsion. Muskrats spend most of their time in the water, and can swim under water for 12 to 17 minutes. They live in families, consisting of a male and female pair and their young. To protect themselves from the cold and from predators, they build nests that are often burrowed into the bank with an underwater entrance. Muskrats feed mostly on cattail and other aquatic vegetation, but also eat small animals.
Ondatra zibethicus is the only species in the genus Ondatra and tribe Ondatrini. It is the largest species in the subfamily Arvicolinae, which includes 142 other species of rodents, mostly voles and lemmings. Muskrats are referred to as “rats” in a general sense because they are medium-sized rodents with an adaptable lifestyle and an omnivorous diet. They are not, however, members of the genus Rattus. They are not closely related to beavers, with which they share habitat and general appearance.
The muskrat’s name probably comes from a word of Algonquian (possibly Powhatan) origin, muscascus (literally “it is red,” so called for its colourings), or from the Abenaki native word mòskwas, as seen in the archaic English name for the animal, musquash. Because of the association with the “musky” odour, which the muskrat uses to mark its territory, and its flattened tail, the name became altered to musk-beaver; later it became “muskrat” due to its resemblance to rats.
Description
An adult muskrat is about 40–70 cm. (16–28 in.) long, half of that length being the tail, and weighs 0.6–2 kg. (1.3–4.4 lb.). That is about four times the weight of the brown rat (Rattus norvegicus); though an adult muskrat is only slightly longer. It is almost certainly the largest and heaviest member of the diverse family Cricetidae, which includes all voles, lemmings, and most mice native to the Americas. The muskrat is much smaller than a beaver (Castor canadensis), with which they often share habitat.
Distribution and ecology
While much wetland habitat has been eliminated due to human activity, new muskrat habitat has been created by the construction of canals or irrigation channels, and the muskrat remains common and widespread. They are able to live alongside streams, which contain the sulfurous water that drains away from coal mines. Fish and frogs perish in such streams, yet muskrats may thrive and occupy the wetlands. Muskrats also benefit from human persecution of some of their predators.
The muskrat is classed as a “prohibited new organism” under New Zealand’s Hazardous Substances and New Organisms Act 1996, preventing it from being imported into the country.
The trematode Metorchis conjunctus can also infect muskrats.
Invasiveness status
In Europe, the muskrat is included since 2017 in the list of Invasive Alien Species of Union concern (the Union list). This implies that this species cannot be imported, bred, transported, commercialised, or intentionally released into the environment in the whole of the European Union. (Source: Wikipedia)