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Nutria

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Nutria
Nutria-899115 1920.jpg
Scientific Classification
Binomial Name

Myocastor coypus

The nutria (Myocastor coypus) is a large semi-aquatic rodent. In most of the world the animal is called coypu, but in North America the animal is called nutria. However, in the rest of the world, nutria is the name of the fur of the animal. Nutrias are native to South America, and have been introduced to Europe, Asia and North America in the previous century because of their luxurious fur and potentially profitable business associated with them. They can survive in all ecosystems that provide enough water.

The nutria looks like a small beaver with long whiskers, short legs and and a fine-haired tail. It also has long incisors that are yellow to orange or orange to red in color. The nutria has a large appetite, and can eat 25% of its own weight every day. It is a herbivore, eating grass, roots, rhizomes and all kind of water plants. It will invade plantations of sugarcane, corn and rice whenever possible. Due to high reproduction rate, nutrias act like invasive species that disturb natural balance in ecosystems. Nutrias are not on the list of endangered species.

Body Design

Nutria's orange incisors

Adult nutrias are described as large rodents that are much larger than the muskrat, but much smaller than the beaver. Their average weight is 15-22 pounds and are typically 16-24 inches in body length.[2] Adult males weigh 12-20 pounds and females weigh 10-18 pounds. Nutrias demonstrate sexual dimorphism (distinct difference in size or appearance between the sexes of an animal in addition to difference between the sexual organs themselves) with the males growing to be larger than the females.[3]

Nutrias have bodies that are highly arched and have large heads. They have small eyes, ears, and nostrils that are located in the upper part of their head. Their big incisors (narrow-edged teeth at the front of the mouth, adapted for cutting) have anterior surfaces that vary in shades of yellow, orange, or red. [4]

Their fur consists of two kinds of hair; their dense underfur is dark grey, and is overlaid by long , thick guard hairs that can be colors of dark brown to yellowish brown. The tip of the muzzle, as well the chin, is covered with white hairs.[5]

Nutrias have long tails that are round and fine-haired,[6]as well as short legs. The hind feet, however, are much longer than the forefeet and have five toes; the first four are connected by webbing, and the fifth is free. The forefeet have four toes that are flexible and are unwebbed , as well as a vestigial thumb.[7]

Besides webbed feet, nutrias have several other traits associated with a semiaquatic life. Their mouth and nostrils have valves that block water from entering while diving, swimming, or feeding underwater. Females have four pairs of thoracic mammae (the milk-secreting organ of female mammals) that are located high up on their sides, and can be suckled by the young while in the water. Nutria can also swim great distances underwater while seeing well enough to avoid being captured by predators.[8]

Life Cycle

A family of nutria

The life cycle of the Nutria consists of a few stages. Nutria breed all year round, which greatly impacts their population and activity rate. Nutria reproduce sexually, and males will reach their sexual maturity at 4-9 months, while females reach sexual maturity at 3-9 months. Nutria are viviparous, and the gestation period takes around 135 days. The newly born pups are born in their colony's den. Average litters of nutria are around 4 to 5. However, the largest recorded litter was 13 pups.[9]

Young nutria are born with hair and are fully active. They are look similar to their parents, and will They are able to swim withing 5 days of birth, and will destroy surrounding marshland along with their parents. Along with eating vegetation, newly born Nutria will nurse for 7-8 weeks. [10]

After nursing Nutria will continue to eat surrounding vegetation and marshland. Nutria may live for up to 6 years. Most Nutria will die off in the first, however, some live for 3 years. Like many rodents, they are colonial animals that live in groups of 2-13 members. In these large colonies Nutria live prosperously together. Sometimes males may either stay in the colony or find a mate from another area. Though many of the Nutria do die off, the ability to reproduce year round breeding allows them to stay prosperous. Nutria will live together in colonies repeating their life cycle, while living their daily life processes.[11]

Ecology

Nutria inside water

Nutria's are aquatic species,[12]so they usually live in coastal areas, and freshwater marshes.[13]They live in burrows, or nests, never far from the water. Nutria may inhabit a riverbank or lakeshore, or dwell in the midst of wetlands.[14]Various wetland types can provide a home to nutria. Nutria habitat, in general, is the semiaquatic environment that occurs at the boundary between land and permanent water. This zone usually has an abundance of emergent aquatic vegetation, small trees, and/or shrubs and may be interspersed with small clumps and hillocks of high ground. In the United States, all significant nutria populations are in coastal areas, and freshwater marshes are the preferred habitat.[15]

Nutria's are originally from southern South America, but as they were transferred to America.[15]In the United States, farm ponds and other freshwater impoundments, drainage canals with spoil banks, rivers and bayous, freshwater and brackish marshes, swamps, and combinations of wetland seemed to provide home for them.[15]

Invasive Species

Nutria eating vegetation

Nutria are native to coastal marshes and lakes of Argentina, Bolivia, southern Brazil, Chile, Paraguay, and Uruguay. They have been introduced into other areas, primarily for fur farming, and feral populations can now be found in North America, Europe, the Soviet Union, the Middle East, Africa, and Japan. Accidental and intentional releases have led to the establishment of widespread and localized populations of nutria in various wetlands throughout the United States. Nutria are generally thought to have been first released into the marshes surrounding New Orleans in the 1930s although the U.S. Geological Survey claims that an earlier population was brought to California in 1899.[16] Introduced into the U.S. as an alternative to mink fur, trappers supposedly recaptured the initial Louisiana population. L.A. McIlhenny kept a nutria ranch on Avery Island, LA where between 12 and 20 nutrias escaped in 1938. A hurricane in the late 1940s also aided the dispersal of 150 additional nutria by scattering them over wide areas of coastal southwest Louisiana and southeast Texas.[17]

Nutria have a more negative effect on the ecosystem than they're worth. They are a very overwhelming addition to any ecosystem. Nutria easily out-compete other animals in the ecosystem for food. Their strict vegetarian diet makes them eat up any surrounding marshland they can find. Nutria consume very rapidly as well. Even from birth, young Nutria are capable of eating raw vegetation. They are known for leaving "eat outs", which are large holes from digging up root mat and devastation the area. Marshes can be destroyed in mass quantities from being overrun with nutria. Unlike many other small rodents nutria have fewer natural predators. As the surrounding population stays in check from day to day hunting, the nutria find themselves safe and untouched inside their burrows. Another issue that the ecosystem is faced with about the nutria is that they breed year round. While many smaller rodents are able to reproduce in larger masses than the nutria, the nutria is capable of breeding year round. A single colony is may be over 10 members, and is such an overwhelming factor in the ecosystem. Many rodents that eat vegetation as well are taking advantage of and may leave or starve. Water foul such as birds and geese are left to damaged marshes where fish and other prey may have left do to loss of habitat. Breeding and hatching grounds are destroyed by nutria quickly and easily, leaving defenseless organisms vulnerable. Nutria may be damaging the ecosystems across America, however they may be controlled. [18]

Land that is well-drained and free of dense, weedy vegetation is generally disliked by nutria. Use of other good farming practices, such as precision land leveling and weed management, can minimize nutria damage in agricultural areas. Any drainage that holds water can be used by nutria as a travel route or home site. Consequently, eliminating standing water in drainage reduces their nutria's want for them. This may be extremely difficult or impossible to accomplish in low-lying areas near coastal marshes and permanent bodies of water. Higher sites, such as those used for growing sugarcane and other crops, are better suited for this type of management. On poorly drained soils, contour small ditches to eliminate low spots and sills and enhance rapid drainage. Use precision leveling on well-drained soils to eliminate small ditches that are occasionally used by nutria. Grading and bulldozing can destroy active burrows in the banks of steep-sided ditches and waterways. In addition, contour bank slopes at less than 45o to discourage new burrowing. Sculpting rice field levees to make them gently sloping is similarly effective. Continued deep plowing of land undermined by nutria can destroy shallow burrow systems and discourage new burrowing activity. Vegetation Control. Eliminate brush, trees, thickets, and weeds from fence lines and turn rows that are adjacent to ditches, drainages, waterways, and other wetlands to discourage nutria. Burn or remove cleared vegetation from the site. Brush piles left on the ground or in low spots can become ideal summer homes for nutria. Water Level Manipulation. Many low-lying areas along the Gulf Coast are protected by flood control levees and pumps that can be used to manipulate water levels. By dropping water levels during the summer, stressful drought conditions that cause nutria to concentrate in the remaining aquatic habitat can be simulated, thus increasing competition for food and space, exposure to predators, and emigration to other suitable habitat. Raising water levels in winter will force nutria out of their burrows and expose them to the additional stresses of cold weather. Water level manipulation is expensive to implement and has not yet been proven to be effective. Nevertheless, this method should be considered when a comprehensive nutria control program is being developed. Other Cultural Methods, alternate field and garden sites should be considered in areas where nutria damage has occurred on a regular basis. New fields, gardens, and slab-on-grade buildings should be located as far as possible from drainages, waterways, and other water bodies where nutria live. Late-planted bald cypress seedlings are less susceptible to damage by nutria than those planted in the spring. For this reason, plant unprotected seedlings in the early fall when alternative natural foods are readily available. [19]

Video

References

  1. M, Danielle and P, Daniel.[1] "Aquatic Nuisance Species Information System". Web. accessed November 12, 2015
  2. Link, Russell. Nutria Washington Department of Fish & Wildlife. Web. Accessed November 16, 2015.
  3. Myocastor coypus Animal Diversity Web. Web. Accessed November 16, 2015. Unknown Author.
  4. Beaver, Muskrat, and Nutria Identification The City of Portland, Oregon. Web. Accessed November 16, 2015. Unknown Author.
  5. [2] Louisiana Wildlife & Fisheries. Web. Accessed November 20, 2015 Unknown Author.
  6. LeBlanc, Dwight. NUTRIA Internet Center for Wildlife Damage Management. Web. Accessed November 12,2015.
  7. [3] U.S. Fish and Wildlife Service. Web. Last updated October 19, 2011. Unknown Author.
  8. LeBlanc, Dwight. NUTRIA Internet Center for Wildlife Damage Management. Web. Accessed November 12,2015.
  9. Link, Russle.[4] Living with Wildlife. Web. accessed November 12, 2015 .
  10. About Nutria.[5] Marsh Dog LLC. Web. accessed November 16, 2015
  11. Scott E. Hygnstrom; Robert M. Timm; Gary E Larson Scott E Hygnstrom; Robert M Timm; Gary E Larson.[6] Internet Center for Wildlife Damage and Management.Web. accessed November 19, 2015
  12. Unknown Author. [7] USDA National Agricultural Library. Web. lastupdate November 18, 2015.
  13. LeBlanc, Dwight. [8] Internet Center for Wild Life Management. Web.accessed - November 13th, 2015.
  14. Unknown Author. [9] National Geographic. Web. Dateofpublication or lastupdate or accessed - specify which.
  15. 15.0 15.1 15.2 LeBlanc, Dwight. [10] Internet Center for Wild Life Management. Web. accessed November 13th, 2015.
  16. Jenkins, Jessica. [11] James A. Danoff-Burg. Web. Last updated February 24, 2002.
  17. [12] Internet Center for Wild Life Management. Web. Accessed -December 2, 2015.
  18. Facts about Nutria Environmental Concern. Web. accessed December 02, 2015
  19. LeBlanc, Dwight. [13] Internet Center for Wildlife Damage Management. Web. Accessed -December 2, 2015.