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Thomas's Water Mouse

Rheomys thomasi
NT · Near threatened Rodentia Cricetidae
Size
12 to 14 cm + tail 13 to 15 cm
Weight
40 to 60 g
Activity
Nocturnal
Sociability
Solitary

Description

He shares with the rest of his genre that rare adaptation to semiacuatic life among American rodents, swimming contracorrent in Central American mountain streams with partially palm-palmed back legs unusual outside the world of specialized aquatic mammals. He lives in the mountain wet forest of a slope stretching from southern Mexico to Central America, always associated with streams of rapid and clean waters from which he depends completely.

How to identify it

Medium-small rodent, dense and waterproof dark brown-tone fur, large and partially palmed back legs adapted to swimming, and long tail used as a steering wheel when swimming. It differs from other semi-water rodents in the region by those palmed back legs so characteristic.

Signs and tracks

Footprints with partially palmed back legs, 2-2.5 cm, with membrane marks between the fingers visible in fine mud along the banks of the river. Small and lengthy feces, 6-8 mm, left on flat stones next to the water. It is sheltered in rocks excavated on the banks, with the entry often below the water level, and its presence is delated by remnants of partially consumed aquatic invertebrates on emerging rocks.

Habitat and range

Rivers and rivers of rapid and well oxygenated waters in mountain wet forests, generally between 1000 and 2500 m of altitude.

Diet

Aquatic carnivore, it feeds on aquatic invertebrates, insect larvae and small crustaceans captured by diving into the water of the streams where it lives.

Behaviour

Solitary and territorial, with a countryside centered on a concrete stretch of river or river.It is probably nocturnal, and its strong dependence on clean waters limits its ability to move between separate basins.

Conservation

Its populations are generally considered stable in much of its distribution area, although in local decline due to the degradation of water quality in some basins of southern Mexico and Central America.

Threats

Contamination and degradation of water quality by agricultural and livestock activities, and deforestation of the river forest in some areas of its distribution area.

Other accounts in Cricetidae

See all species accounts for rodents · Full species index

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