Peromyscus crinitus

Canyon Deermouse
(*Peromyscus crinitus*)
Canyon Deermouse (Peromyscus crinitus)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Supramyomorpha
Infraorder:	Myomorphi
Superfamily:	Muroidea
Family:	Cricetidae
Subfamily:	Neotominae
Tribe:	Peromyscini
Genus:	Peromyscus
Binomial details
	Peromyscus crinitus (Merriam, 1891)

Description

From Johnson & Armstrong (1987): "Size small to medium for genus; tail generally longer than head and body except in some northern populations; ears large, about same length as hind foot, sparsely haired. Dorsal color geographically variable. Hair Brown overlain with ochraceous in P. c. crinitus-northern Nevada, Oregon, Idaho; Light Ochraceous-Buff, lightly overlain with dusky in P. c. pergracilis- Bonneville Basin; Light Ochraceous-Buff overlain with brownish or blackish in P. c. stephensi and P. c. disparilis-lower Colorado drainage and southern California; Pale Ochraceous-Buff overlain with brownish and dusky in P. c. pallidissimus- an insular form in the Sea of Cortez; Chaetura Drab in P. c. delgadilli Pinacate Lava Flow, Sonora; Ochraceous-Buff in P. c. auripectus Colorado Plateau (Hall and Hoffmeister, 1942); Light Ochraceous Buff to Light pinkish Cinnamon in P. c. doutii- Uinta Basin (Goin, 1944). Individuals darker dorsally tend to have clear buffy lateral line. Venter white (except in P. c. delgadilli), hairs gray at base; buffy to ochraceous pectoral patch (especially pronounced in P. c. auripectus, perhaps least so in P. c. doutii); venter sometimes faintly washed with buff; ochraceous anal patch sometimes present. As in some other rodents, canyon mice sometimes have the general color of their characteristic substrate, thereby forming microgeographic color races."

From Armstrong et al. (2010) for Colorado: "The canyon mouse is small to medium-sized with ears as long as the hindfoot. The tail is generally longer than the head and body. The fur is long and silky with the dorsal color a bright ochraceous buff. The bases of hairs are lead gray. The sides are even more brightly colored than the back. A yellow-orange to buff pectoral spot is generally present in Coloradan populations. The belly is white to gray and the feet are white. The bicolored tail, typically longer than the head and body, has pronounced terminal tuft, and the scales are usually visible through the thin covering of hair."

From Hoffmeister (1986) for Arizona: "A small-sized Peromyscus, tail longer than the head and body, ear not large and about equal in length to the hind foot, fur long and silky, dorsal coloration variable but in Arizona mostly bright orangeish to buff." Additionally, "in Arizona canyon mice in the northern part of the state are of large size and bright color; those along the lover Colorado River paler and smaller." In reference to P. crinitus auripectus, Hoffmeister (1986) states: "A subspecies of P. crinitus with a long body, short tail, tail about 110 to 120 percent of the body, long hind foot, underparts often with a buffy pectoral spot, dorsal coloration a bright ochraceous, skull large." In reference to P. crinitus stephensi: "with a short body, tail of medium length, tail about 130 to 145 percent of the body, pectoral spot on underparts usually absent and inconspicuous, skull small, zygomata compressed anteriorly." In reference to P. crinitus pergracilis: "with a medium to long body and short tail, length of tail about 105 to 115 percent of the body, pectoral spot absent usually, skull of medium size, color of dorsum variable but never bright ochraceous (as in auripectus)." In reference to P. crinitus disparilis: "with a short body, long tail, tail about 145 percent of the body, small skull, zygomata greatly compressed anteriorly, color of dorsum pale."

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
California	Jameson & Peeters (2004)	161–192	80–118	17–23	17–21	13–18
Colorado	Armstrong et al. (2010)	160–190	82–110	18–25	17–23	12–30
rangewide	Johnson and Armstrong (1987)	males: 162–186; females: 164–191	males: 82–101; females: 79–118	males: 18–25; females: 18–22	males: 17–23; females: 18–22	males: 12.8–20.5; females: 12.6–22.9

Color variation

From Hoffmeister (1986): "Since P. crinitus is highly restricted to rocky situations, and since there is a wide range of color variation of rocky substrate in the Southwest, evolutionary processes have resulted in a series of populations that differ noticeably in color. Examples of this are the blackish canyon mice from Sierra del Pinacate of northwestern Sonora; the pale-colored mice of the light rock of the Gila Mountains, Yuma County; the reddish mice of the red sandstone of northeastern Arizona; dark animals from Black Peak near Parker, Yuma County (juveniles are especially dark); and grayish animals (but one is nearly black) at St. George, Utah. Populations that are cryptically colored are encountered frequently within this species."

Skull

From Armstrong et al. (2010): "The maxillary toothrow is typically less than 4 mm long. The skull is fragile with a long, slender rostrum. Zygomatic breadth is only slightly greater than cranial breadth. The nasals are long, narrowing posteriorly. The premaxillary ends at about the level of the posterior margin of the nasals."

From Johnson & Armstrong (1987): "Skull rather delicate; braincase broad, shallow, flattened, rounded in dorsal view; rostrum relatively long and slender, slightly depressed, more or lessrounded dorsally; nasals long, slender, somewhat compressed posteriorly; infraorbital canal high, relatively narrow; zygomata rather delicate, zygomatic breadth not much greater than cranial breadth; ascending branches of premaxillae usually attenuate and rarely extending behind nasals; auditory bullae of moderate size; maxillary toothrow short; palate nearly as long as incisive foramina. Dental pattern simple, much like P. eremicus; accessory lophs typically absent; presence of accessory styles geographically variable; when present, unattached to neighboring cusps or lophs; no mesoloph; lower teeth simpler than upper teeth, no meso- or ectolophids, and stylids small and present in one-third of sample; details and frequency distributions of dental traits provided by Hooper (1957). Armstrong (1979), Hall (1946), Hall and Hoffmeister (1942), and Kelson (1951) provided additional comments on phenotypic variation."

Image needed. Please let us know if you have have an image that you would like to contribute.

This illustration of the right upper molar M2 from Hooper (1957) is shown to assist with identifying structures of the upper molars.
This illustration of the left lower m2 molar from Hooper (1957) is shown to assist with identifying structures which may be present on the lower molars.

Similar species

Comparison with Peromyscus boylii

Peromyscus crinitus differs from the Brush Deermouse (Peromyscus boylii) in having a tail with a pronounced terminal tuft. While the length of tail> total length of body in P. boylii, the length of the tail relative to body length in P. crinitus varies by population.

Peromyscus crinitus
Brush Deermouse (Peromyscus boylii)

Comparison with Peromyscus gambelli and P. sonoriensis

Peromyscus crinitus can be differentiated from the No common name found for Peromyscus gambelli and the Western Deermouse (Peromyscus sonoriensis) by its relatively long tail that has a pronounced terminal tuft.

Gambel's Deermouse (Peromyscus gambelii)
Western Deermouse (Peromyscus sonoriensis)

Comparison with Peromyscus fraterculus

Peromyscus crinitus can be differentiated from the Northern Baja Deermouse (Peromyscus fraterculus) by its dorsal coloration and relatively long tail that has a pronounced terminal tuft. The tail of P. fraterculus is also long, but is nearly naked and lacks a pronounced terminal tuft.

Peromyscus crinitus
Northern Baja Deermouse (Peromyscus fraterculus). Photograph by Patricia Simpson.

Comparison with Peromyscus truei

Peromyscus crinitus can be differentiated from the Pinyon Deermouse (Peromyscus truei) by its relatively long tail that has a pronounced terminal tuft. The tail of P. truei is scantily haired and lacks a pronounced terminal tuft. Both species have large ears. In P. crinitus, the ear measured from the notch is about equal to the length of the hind foot. In P. truei, the ear is equal to or longer than the hind foot in most populations.

Peromyscus crinitus
Pinyon Deermouse (Peromyscus truei)

References

Armstrong DM. 1979. Distributional checklist of rodents of Canyonlands National Park, Utah. Occas. Papers Mus., Texas Tech Univ., 59: 1-44

Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.

Hall ER. 1946. Mammals of Nevada. Berkeley and Los Angeles (CA, USA): University of California Press.

Hall ER, Hoffmeister DF. 1942. Geographic variation in the canyon mouse, Peromyscus maniculatus. Journal of Mammalogy 23:51-65.

Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.

Hooper ET. 1957. Dental patterns in mice of the genus Peromyscus. Miscellaneous Publications University of Michigan Museum of Zoology 99:1-59.

Jameson EW, Peeters HJ. 2004. Mammals of California (No. 66). Berkeley (CA, USA): University of California Press.

Johnson DW, Armstrong DM. 1987. Peromyscus crinitus. Mammalian species (287): pp.1-8.

Kelson KR. 1951. Speciation in rodents of the Colorado River drainage. BioI. Ser., Univ. Utah, 11:1-125.

Merriam, C.H. 1891-07-30. Mammals of Idaho. North American Fauna 5:31-88.