coipo and nutrias

myocastoridae

Nutria - Coipo

PHYLUM: Chordata	CLASS: Mammalia	SUBCLASS: Eutheria	ORDER: Rodentia	SUBORDER: Hystricognathi	FAMILY: Myocastoridae
Genera: Myocastor	Biology	Ecology
Specie: coipus	Biology
	The single Recent species in this family was originally restricted to central and southern South America, but it has been introduced widely in the United States and Europe. Nutria are large rodents, weighing up to 10 kg. They have a robust body that shows many indications of their aquatic lifestyle. The ears and eyes are small. The webbed hind feet are large and have 5 toes. Four toes are found on the forefeet, which lack webbing. All toes have well-developed claws. The tail is long, scantily furred, and rounded. It is not compressed as in beavers or muskrats. Like many aquatic mammals, nutria have thick, soft underfur overlain with long and coarse guard hairs. Their color is dark dorsally and whitish yellow on the underside. The cranium of a nutria is massively built, with well-developed ridges (including a sagittal crest) and a deep rostrum. Nutrias are hystricomorphous, and their infraorbital foramina lack a distinct groove for the passage of nerves to the rostrum. The zygomatic arches are heavy and broad, but the jugal does not contact the lacrimal. On the ventral surface of the skull, the auditory bullae are small but the paroccipital processes are unusually long. The lower jaws are strongly hystricognathous. The coronoid process is reduced to little more than a knob. Nutrias have the following dental formula: 1/1, 0/0, 1/1, 3/3 = 20. The molars are hypsodont, flat-crowned, and rooted. The upper molars have two labial and two lingual folds, while the lowers have one labial and three lingual. The incisors are massive and chisel-like, deeply orange-yellow in color. Nutria are primarily herbivorous, feeding on vegetation on land and in shallow water, but they also consume some invertebrates.
	Ecology

	They are excellent swimmers, capable of staying underwater for up to around 5 minutes. They prefer slow-moving streams, lakes, and brackish or freshwater marshes. They are good diggers, constructing burrows in river banks. Nutria often live in groups of up to 10-15 individuals, usually made up of parents and offspring. The fur of these animals has been the basis of a considerable industry, first in their native South America, and more recently in the United States. Nutria have been introduced many times to North America and Europe, both intentionally and accidentally as a result of escapes from fur farms. They can be tremendously destructive to both wild vegetation and to agriculture.

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