Chaetodipus californicus

California Pocket Mouse
(*Chaetodipus californicus*)
California Pocket Mouse (Chaetodipus californicus)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Supramyomorpha
Infraorder:	Castorimorphi
Superfamily:	Geomyoidea
Family:	Heteromyidae
Subfamily:	Perognathinae
Genus:	Chaetodipus
Binomial details
	Chaetodipus californicus (C. H. Merriam, 1889)
Other resources
	Full taxonomic details at MDD

The California Pocket Mouse (Chaetodipus californicus) is a large pocket mouse found mainly in chaparral habitat. Its range includes California and northern Baja California, Mexico.

Description

From Patton & Alvarez-Castañeda (1999): "This is among the largest species in the genus, along with C. baileyi and C. hispidus. It is characterized by a relatively long, strongly crested and pencillate tail; numerous stiff spines on the rump, sometimes extending to the sides; relatively long and square-tipped ear pinna; and relatively small mastoid bullae with a broad interparietal. The ratio of the length of the tail to head and body ranges from about 1.15 to 1.55; the ear is more than 10 mm in length (from the notch); and the width of the interparietal is usually greater that 8.1 mm. This species is typically dark, grizzled, reddish-brown, with a sharply evident buff-colored lateral line separating the dorsal pelage from the self-color white venter."

From Jameson & Peeters (2004): "A rather large pocket mouse with a mixture of yellow and black hairs dorsally and strong, spiny hairs on its sides and rump. The heel of the hind foot is naked. The ears are unusually long (9-14 mm)."

Museum type specimens

Holotype: USNM 186506. Chaetodipus californicus californicus. Adult female. Berkeley, Alameda County, California. Collected 8 November 1888. Dorsal view.
Holotype: USNM 186506. Chaetodipus californicus californicus. Adult female. Berkeley, Alameda County, California. Collected 8 November 1888. Lateral view.
Holotype: USNM 186506. Chaetodipus californicus californicus. Adult female. Berkeley, Alameda County, California. Collected 8 November 1888. Ventral view. The fur-lined cheek pouches are expanded.

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)	190–235	103–143	24–29		16–21
not reported	Ceballos (editor, 2014)	190–235	103–143	24–29	9–14	16–21

Skull

From Jameson & Peeters (2004): "The auditory bullae are separated anteriorly. The interparietal bone is nearly twice as wide as it is long."

Holotype: 32116/43928. Chaetodipus californicus dispar. Adult male. Carpenteria, Santa Barbara County, California. Collected 19 December 1891. Dorsal view of the skull.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult. Arrows identify the interorbital width. The interparietal bone is colored yellow. The interparietal width is greater than the interorbital width.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult male. Carpenteria, Santa Barbara County, California. Collected 19 December 1891. Ventral view of the skull.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult male. Carpenteria, Santa Barbara County, California. Collected 19 December 1891. Lateral view of the skull.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult male. Carpenteria, Santa Barbara County, California. Collected 19 December 1891. Dorsal view of the mandible.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult male. Carpenteria, Santa Barbara County, California. Collected 19 December 1891. Lateral view of the left mandible.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult. Upper molars.
Holotype: 32116/43928. Chaetodipus californicus dispar. Adult. Lower molars.

Similar species

In the USA, Chaetodipus californicus is sympatric or near-sympatric with the following species of pocket mice: San Diego Pocket Mouse (Chaetodipus fallax), Long-tailed Pocket Mouse (Chaetodipus formosus), Desert Pocket Mouse (Chaetodipus penicillatus), Peninsular Pocket Mouse (Chaetodipus rudinoris), Spiny Pocket Mouse (Chaetodipus spinatus), White-eared Pocket Mouse (Perognathus alticolus), San Joaquin Pocket Mouse (Perognathus inornatus), and Little Pocket Mouse (Perognathus longimembris). The presence of pronounced rump spines distinguishes Chaetodipus californicus from the Desert Pocket Mouse (Chaetodipus penicillatus), Peninsular Pocket Mouse (Chaetodipus rudinoris), and all pocket mice in the genus Perognathus in the USA. Two other species of Chaetodipus with pronounced rump spines occur in southern California, the Spiny Pocket Mouse (Chaetodipus spinatus) and the San Diego Pocket Mouse (Chaetodipus fallax). The presence of a well-marked lateral line distinguishes Chaetodipus californicus from the Spiny Pocket Mouse (Chaetodipus spinatus). According to Patton and Alvarez-Castañeda (1999), when comparing Chaetodipus californicus with the San Diego Pocket Mouse (Chaetodipus fallax), californicus is "distinctly larger in size, with longer and obviously more square-topped as opposed to rounded ears."

California Pocket Mouse (Chaetodipus californicus). Arrow points to the well-defined, buff-colored lateral line.
The ears of the California Pocket Mouse (Chaetodipus californicus) are more square-topped (as the black lines attempt to show) as opposed to rounded. Original image by Boaz Benaiah Solorio.
The Spiny Pocket Mouse (Chaetodipus spinatus) observed by Charles A. Drost and Jan Hart, USGS. The lateral line is faint or absent in this species.
San Diego Pocket Mouse (Chaetodipus fallax) observed in Riverside County, California, by Caleb Villar. The lateral line is pinkish buff in this species.

References

Ceballos G, editor. 2014. Mammals of Mexico. Baltimore (MD, USA): Johns Hopkins University Press.

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

Merriam CH. 1889. Revision of the North American pocket mice. North American Fauna 1:1-29.

Patton JL, Alvarez-Castañeda ST, editors. 1999. Family Heteromyidae. Mamiferos del noroeste de México. La Paz (Baja California Sur, MX): Centro de Investigaciones Biológicas del Noroeste.