Mammaling
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Carmen Mountain Shrew

Sorex milleri
VU · Vulnerable Eulipotyphla Soricidae
Carmen Mountain Shrew (Sorex milleri)
Photo: © Ricardo Jaimes-López, some rights reserved (CC BY)
Size
6-8 cm + tail 4-5 cm
Weight
6 to 10 g
Activity
Variable (day and night)
Sociability
Solitary

Description

It lives in a handful of isolated mountainous masses of northeast Mexico, each population separated from the others by arid valleys that act as an infranqueable barrier for an animal so little given to move on open and dry ground. Like the rest of musarañas, it has an extraordinary accelerated metabolism that obliges it to feed almost without rest, a biological requirement that limits its presence to the fragments of mountain wet forest where it finds enough invertebrates. Its name pays tribute to an American mastozoologist who documented a good part of the fauna of small mammals of northern Mexico and the east of the United States.

How to identify it

Small-sized musaraches, gray brown fur, long and mobile fox, and tiny eyes barely visible between the fur, are confused with other musaraches from the northern Mexican mountains, whose reliable separation often requires cranial or genetic analysis; their presence in mountainous massifs isolated by desert helps to guide identification.

Signs and tracks

Minuscule footprint, barely 1-1.2 cm, rarely visible except on very fine substrate. Minuscule, dark excretions, of a few millimeters, with remains of insect cutlery, left scattered by paths under the wet leafy of the mountain forest fragments where he lives. Build surface galleries under the leafy and spherical nests in holes under fallen trunks.

Habitat and range

Mountainous forest, in isolated massives surrounded by arid terrain, generally between 2000 and 3000 m of altitude.

Diet

Insectívora, it feeds on insects and other invertebrates from the mountain forest soil, caught thanks to a very accelerated metabolism.

Behaviour

Continuous activity distributed in short periods throughout the day and night due to its very accelerated metabolism, with a solitary and territorial behavior.

Conservation

Its populations are considered to be declining due to the continued loss of mountain wetlands that it depends on, with a fragmented distribution among different isolated massives in northeastern Mexico.

Threats

Deforestation and degradation of mountain forests by deforestation and changes in land use, and intrinsic isolation between different mountain populations.

Other accounts in Soricidae

See all species accounts for hedgehogs and shrews · Full species index

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