Peromyscus nasutus
Northern Rock Deermouse
(Peromyscus nasutus) | |
---|---|
Range | |
![]() | |
Taxonomic classification | |
Order: | Rodentia |
Suborder: | Supramyomorpha |
Infraorder: | Myomorphi |
Superfamily: | Muroidea |
Family: | Cricetidae |
Subfamily: | Neotominae |
Tribe: | Peromyscini |
Genus: | Peromyscus |
Binomial details | |
Peromyscus nasutus (J. A. Allen, 1891) |
Originally treated as one species, Peromyscus difficilis, Zimmerman et al. (1975, 1978) elevated Peromyscus nasutus to species status. The range of Peromyscus nasutus includes both the United States and Mexico, whereas Peromyscus difficilis is a Mexican endemic.
Description
From Armstrong et al. (2010) for Colorado: "The northern rock mouse is a long-eared mouse, rather similar in appearance to the piñon mouse [Peromyscus truei]. However, the pelage is grayish brown, less buffy than that of the piñon mouse, with whitish to silver-gray underparts. Furthermore, the bicolored tail is usually slightly longer than the head and body, and the ears usually are less than 22 mm long, equal to or shorter than the hindfoot."
From Hoffmeister (1986) for Arizona: "A large Peromyscus (for Arizona) with the tail usually equal to or longer than the head and body; hind feet large (usually 23 to 25 mm) and always longer than ear, which is of moderate size ... color of upper parts dark grayish, with sides and top of head lighter than back."
From Schmidly & Bradley (2016) for Texas: Rather large, long-tailed, grayish buff mouse; tail sharply bicolor, brownish to blackish above and white below, slightly tufted, tops of front and hind feet (including ankles) white; ears about as long as hind feet.
External measurements
Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.
Part of range | Reference | Total length | Tail length | Hindfoot length | Ear length | Mass |
---|---|---|---|---|---|---|
Arizona (Apache Co.) | Hoffmeister (1986) | 190–211 (n=14) | 91–108 (n=14) | 22–24 (n=14) | 20–23 (n=14) | |
Arizona (Apache Co.) | Hoffmeister (1986) | 190–226 (n=17) | 97–123 (n=17) | 23–25 (n=17) | 20–24 (n=17) | |
Arizona, New Mexico, Texas | Diersing (2023) | head and body: 88–106 (n=38) | 91–124 (n=37) | 22–25 (n=39) | 20–24 (n=37) | |
Colorado | Armstrong et al. (2010) | 170–200 | 80–100 | 22–25 | 21–24 | 25–30 |
not reported | Ceballos (editor, 2014) | 220–241 | 121–134 | 22–26 | 21–26 | 25–35 |
Texas | Schmidly & Bradley (2016) | 193 | 104 | 22.5 |
Similar species
From Armstrong et al. (2010): "Peromyscus nasutus is closely related to P. truei (E. Zimmerman et al. 1978; Janacek 1990), so great care should be taken in distinguishing the species where they are sympatric, as they are in southern Colorado. No definitive cranial characteristics easily distinguish the rock mouse from either the piñon mouse [Peromyscus truei] or the brush mouse [Peromyscus boylii], although the rostrum of the rock mouse usually is distinctively slender and long."
Skull characters

References
Allen JA. 1891. Notes on new or little-known North American mammals, based on recent additions to the collection of mammals in the American Museum of Natural History. Bulletin of the American Museum of Natural History, 3, 299.
Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.
Ceballos G, editor. 2014. Mammals of Mexico. Baltimore (MD, USA): Johns Hopkins University Press.
Diersing VE. 2023. Merriam's Pinyon Mouse, Peromyscus gratus, in the United States: Distribution and Recognition. The Southwestern Naturalist 67(4): 244-254.
Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.
Janecek LL. 1990. Genic variation in the Peromyscus truei group (Rodentia: Cricetidae). Journal of Mammalogy 71(3): 301-308.
Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.
Zimmerman EG, Hart BJ, Kilpatrick CW. 1975. Biochemical genetics of the boylii and truei species groups of the genus Peromyscus (Rodentia). Comparative Biochemistry and Physiology, B. Comparative Biochemistry 52: 541-545.
Zimmerman EG, Kilpatrick CW, Hart BJ. 1978. The genetics of speciation in the rodent genus Peromyscus. Evolution, pp.565-579.