By digging its underground galleries, the muskrat weakens the banks to the point of increasing the risk offlood. Fond of vegetable and cereal crops, rodents are also carriers of diseases transmissible to humans. So many arguments that have placed the mammal in the category of species harmful.
Presentation of the muskrat
The muskrat (Ondatra zibethicus) is a rodent semi-aquatic herbivore belonging to the Rodentian order and the cricetidae family. Native to North America, the mammal was introduced to Europe in the XIXe century for the exploitation of its fur. Individuals from farms escaped or were released by ruined breeders during the 1929 crisis, allowing the species to colonize the natural environment. The animal owes its name to glands musk (called preputial glands), which produce an odorous substance aimed at marking its territory.
Description of the muskrat
With its massive body extended by a broad head, a short muzzle, long vibrissae and small ears, the muskrat looks like a big countrysidel. Its long tail flattened laterally, blackish and scaly, as well as its five-toed paws fringed with hair, make it a very good swimmer. The herbivore has 16 teeth including 4 long incisors yellow. Its very thick fur and raincoat displays a dark brown color on the back and lighter on the belly. The muskrat measures between 30 to 40 cm to which must be added 20 to 30 cm of tail length. It weighs between 1kg and 2kg.
The muskrat is found in much of western and northern Europe as well as in France except in the extreme South East. The permanent proximity of shallow, stagnant or running water low marked by the presence of aquatic vegetation and molluscs constitute favorable conditions for the installation of the rodent. In fact, the mammal chooses its habitat near ponds, lakes, rivers, marshes or wet meadows. It digs its burrow along the banks, providing it with at least one opening underwater to reach his gallery without having to go through dry land.
This species vegetarian feeds mainly on aquatic plants (cattails, rushes, water lilies) and other shore plants but also various grasses found on the ground. In winter, when the vegetation becomes scarce, the muskrat does not disdain the mollusks such as freshwater mussels, crustaceans such as crayfish or even fish, amphibians and other insects. Essentially nocturnal, he goes in search of food as soon as night falls.
Animal solitary lives alone or in small family groups composed of male, female and young of the year. After having spent the night feeding, the muskrat spends the day deep in its burrow, sheltered from predators. In winter, when temperatures drop below freezing, family members huddle together in their den. Excellent swimmer, thanks to its semi-webbed hind legs, the mammal evolves most of the time in water. Its long scaly tail flattened at the sides is a great asset for swimming amphibious : the rodent can indeed practice apnea for up to 15 minutes, either by swimming, or by hiding in case of danger.
Reproduction of muskrat
Very species prolific, muskrat reaches sexual maturity at one year of age. Both males and females secrete a strong or musky odor to warn their partner of their availability to mating that occurs in spring and summer. After a gestation of one month, the female gives birth 6 to 7 young. At the rate of 2 to 3 annual litters, these are between 12 and 21 small that may be born each year and that the mother will breastfeed for 20 to 30 days.
Muskrats adults have few predators. Among these are the fox, marten, buzzard, otter, mink and some snakes. In case of danger, his first defense remains the escape in water. If it is on the ground, the rodent can use its two pairs ofincisors to inflict serious injury on his enemies. The lifespan of the muskrat is 4 to 5 years in the wild.
By digging its underground galleries, the muskrat causes considerable damage: it weakens the land, causeserosion banks, deteriorates the dikes of ponds and hydraulic structures, thus increasing the risk offloods. In the event of food shortage, the animal can also attack cultures vegetable crops, corn, rapeseed, cereals, potatoes or beets. Finally, the rodent is vector of diseases (leptospirosis, Lyme) transmissible to humans and animals.
The muskrat is classified harmful in France and belongs to the so-called species invasive in Europe. Considering the impact of the rodent on the ecosystem and the environment, the risks sanitary and the spread of disease, orders prefectural set the periods and methods for destroying the muskrat. The authorized control methods are mainly the trapping and shooting.