This species is endemic to Mexico, distributing their populations from southern Sonora to Oaxaca, and even the Islas Marias on the Pacific coast. There are also isolated records of this species in the center of the Yucatan Peninsula. Voss and Jansa point (2003) that there is some evidence of the presence of this small marsupial in Guatemala, no data has been definitively confirmed. There is great variability in individual appearance Marmosa copies of gray, especially among populations that inhabit the Yucatan and are distributed along the west coast. However, there is no apparent evidence of sexual dimorphism. They are animals of small size, possibly, according to Zarza, Ceballos and Steele (2003), marsupials smaller than we find in Mexican lands, which together with its color gray is clearly distinguishable from the Mexican Marmosa reddish makes this species is easily identifiable. The eyes are framed by two circles black hair and ears are round, wide and bare. The tail is prehensile capacity and is partially covered with hair. Usually grow to about the same as the body (head + trunk).
Although you can find in many varied habitats, prefers mixed forests in which seasonal change is noticeable to a height of 2,100 meters.
This specimen was photographed in his den, in the Biosphere Reserve Chamela-Cuixmala. In Chamela Biology Station, part of the UNAM.