Mammal Species of the World
Click here for The American Society of Mammalogists species account
Peromyscus californicus is found from San Francisco Bay south and east along the coast ranges and in the eastern Sierra Nevada from Mariposa Co. south to Kern Co. in California south to Bahia San Quintin on the Pacific coast of northwestern Baja California (Bryiski and Harris, 1984; Alvarez-Casteñada and Cortés-Calva, 1999).
Biogeographic Regions: nearctic (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: San Francisco Bay region and central Sierra Nevada foothills south, west of the Mohave Desert and not including the San Joaquin Valley, to northern Baja California (see map in Carleton 1989).
Peromyscus californicus is the largest species in its genus. Its total length is between 220-285 mm, with tail length ranging from approximately 117-156 mm (Whitaker 1997). It is distinctly bicolored. Adults have a yellowish brown or gray mixed with black dorsal coloring, and a white underside, and feet. Many individuals have a distinctly fulvous throat patch and a fulvous lateral line separating dorsal from ventral pelage in the shoulder region, sometimes extending to the thigh. Juveniles are gray on top with a white underside. The tail matches the dorsal pelage and is not sharply bicolored. The ears are large, ranging from 20-25 mm (Whitaker 1997).
Range mass: 33.2 to 54.4 g.
Range length: 220 to 285 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average basal metabolic rate: 0.267 W.
Length: 29 cm
Weight: 54 grams
Size in North America
Range: 220-285 mm
Range: 33.2-54.4 g
Peromyscus californicus is generally restricted to dense chaparrel and broad-sclerophyll woodland (Meritt 1974). The limiting factor for its small geographic range may be the need for naturally occurring burrow holes of the proper size for these larger animals (Grinnell and Orr 1934), as they are poor natural burrowers. The co-occurrence of woodrat houses and a distributional association with the California laurel complex have also been noted as potential limiting factors (Meritt 1974), although there is no direct evidence to implicate any of these.
Range elevation: 2440 (high) m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: chaparral ; forest
Habitat and Ecology
Finds cover in natural holes and crevices and uses burrows of other animals. Often lives in stick nests built by wood rats. Young are born in complex nests of grasses, weeds and sticks located under logs or other debris.
Comments: Chaparral and foothill oak woodland, Upper Sonoran life zone, moist laurel and redwood forests (Merritt, in Wilson and Ruff 1999). Finds cover in natural holes and crevices and uses burrows of other animals. Often lives in stick nests built by wood rats. Young are born in complex nests of grasses, weeds and sticks located under logs or other debris.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Peromyscus californicus specializes on the fruits, seeds and flowers of shrubs (Meserve 1976). In woodland habitat the seeds of California bay laurel (Umbellularia californica) are the major food (Meritt 1974). Arthropods may make up a small percentage on the diet but these are not actively hunted (Meserve 1976). Water is most likely obtained from the food that it eats and supplimented with dew; P. californicus is not as good at water conservation as other species in the genus (Meritt 1974).
Animal Foods: insects
Plant Foods: leaves; seeds, grains, and nuts; fruit; flowers
Primary Diet: herbivore (Frugivore , Granivore )
Comments: Shrub fruits, seeds, and flowers. Other foods sometimes eaten include grasses, forbs, fungi, and arthropods. Often associated with bay (UMBELLULARIA CALIFORNICA), may feed on its seeds.
California mice are important seed predators in the ecosystems in which they live and they form an important prey base for rattlesnakes, owls, and other predators.
California mice, like other Peromyscus species, are an important prey base for many predators throughout their range. They are preyed on by hawks, owls, rattlesnakes, and small mammalian predators. Their nocturnal and secretive habits help to protect them from many predators.
- western rattlesnakes (Crotalus oreganus)
- barn owls (Tyto alba)
Anti-predator Adaptations: cryptic
More territorial than P. MANICULATUS; nest site defended by both males and females. Density estimates vary with habit (Merritt 1978). Life expectancy in field 9-18 months. In Monterey County, females dispersed farther than did males; females up to 790 m (mean 155), males up to 450 m (mean 70) (Ribble 1992).
Life History and Behavior
Like other Peromyscus species, California mice have keen vision and hearing and use chemical cues extensively in communication.
Communication Channels: visual ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Comments: Active throughout the year; primarily nocturnal.
California mice generally live for 9 to 18 months. Populations tend to be fairly stable and at low densities, as compared to other Peromyscus species.
Status: wild: 9 to 18 months.
Status: captivity: 5.5 years.
Lifespan, longevity, and ageing
Unlike most mice P. californicus is truly monogamous, and once mated will stay paired for life (McCade and Blanchard 1950; Ribble 1991; Ribble and Salvioni 1990; Guvernick and Nelson 1990).
Mating System: monogamous
Mating may occur year round, but mainly from March to September. In the lab P. californicus can have up to 6 litters per year, but in the wild the average is 3-4. Gestation is 30 to 33 days and average litter size is 2 (from 1 to 3), with a slight increase in litter size with the age of the female. Compared to other species of Peromyscus, P. californicus young are rather precocious, although weaning is not completed for about 5 weeks. They also have a long period before reaching sexual maturity, approximately 11 weeks for females and even longer for males.
Breeding interval: Females can have up to 6 litters per year, but 3 to 4 is more typical.
Breeding season: Breeding can occur year round but most breeding occurs from March to September.
Range number of offspring: 1 to 3.
Range gestation period: 30 to 33 days.
Average weaning age: 5 weeks.
Average age at sexual or reproductive maturity (female): 11 weeks.
Range age at sexual or reproductive maturity (male): 11 (low) weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 4.46 g.
Average number of offspring: 2.
Average age at sexual or reproductive maturity (female)
Sex: female: 46 days.
Males help extensively in caring for and protecting the young.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
In Monterey County, breeds throughout most of the year (mainly December-May), with few pregnant or lactating females present from mid-summer until onset of fall or winter rains (Ribble 1992). Average of 2-3 litters/female/year. in central California. Gestation 31-33 days in nonlactating females (extended several days in lactating females due to delayed implantation); gestation also reported as averaging 23-24 days in nonlactating females (see Kirkland and Layne 1989); mean age of first estrus 44 days (Gubernick 1988). Litter size 1-3 (usually 2). Interbirth interval 1-3 months within single breeding season. Average of 4 young/female/season. Persistent association between paired male and female; male displays extensive parental care; monogamous. See Ribble (1992) for further details.
Despite its relatively narrow habitat, limited geographic range, and generally low population densities, Peromyscus californicus populations remain healthy.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Lower Risk/least concern(Baillie and Groombridge 1996)
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Low, but stable densities, with populations up to 104 individuals/ha depending on habitat and season. Appears to associate with Neotoma fuscipes, with densities possibly correlating with abundance of Neotoma dens.
Relevance to Humans and Ecosystems
Like other members of Peromyscus, California mice fecal matter may transmit hantavirus.
Negative Impacts: injures humans (carries human disease)
The California mouse (Peromyscus californicus) is a species of rodent in the family Cricetidae. It is the only species in the Peromyscus californicus species group. It is found in northwestern Mexico and central to southern California. It is largest Peromyscus species in the United States.
The California mouse has very large ears, and its tail is longer than the head and body combined. Including the tail, which is about 117 to 156 mm long, the mouse ranges in length from 220 to 285 mm. The coat is overall brown, mixed with black hairs. This dorsal colour shades to a creamy-white belly colour. The manus and feet are white. Adults are large enough that they can be confused with juvenile pack rats.
The California mouse is semiarboreal, but tends to nest on the ground, under debris such as fallen logs. Nests are insulated with coarse, dry grasses, weeds, and sticks, and fine grass is used as bedding in the center chamber. P. californicus is more strongly territorial than P. maniculatus, with both sexes defending the nest site. Males are also aggressive toward one another; their fighting techniques involve jumping, avoidance, and a characteristic mewing cry.
The California mouse pair bonds and the males help raise the young. A litter usually consists of only two pups, but a pair may produce as many as six litters in a year. Gestation ranges from 21 to 25 days. Weaning occurs when the offspring are five to six weeks of age.
- Linzey, A.V., Timm, R., Álvarez-Castañeda, S.T. & Lacher, T. (2008). Peromyscus californicus. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 27 August 2009. Database entry includes a brief justification of why this species is of least concern.
- Grinnell, J and Orr, RT 1934 (1934). "Systematic review of the californicus group of the rodent genus Peromyscus". Journal of Mammalogy 15 (3): 210–220. doi:10.2307/1373853.
- Musser, G. G. and M. D. Carleton. (2005). Superfamily Muroidea. pp. 894–1531 in Mammal Species of the World a Taxonomic and Geographic Reference. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.
- Crossland, J. and Lewandowski, A. (2006). "Peromyscus – A fascinating laboratory animal model". Techtalk 11: 1–2.
- Osgood, WH (1908). "Revision of the mice of the American genus Peromyscus". North Am. Fauna 28: 1–285. doi:10.3996/nafa.28.0001.
- Allen, JA (1896). "On mammals from the Santa Cruz Mountains, California". Bull. Am. Mus. Nat. Hist. 8: 263–270. hdl:2246/752.
- Clark, FH (1936). "Geotropic behavior on a sloping plane of arboreal and non-arboreal races of mice of the genus Peromyscus". Journal of Mammalogy 17: 44–47. doi:10.2307/1374549.
- McCabe, TT and BD Blanchard. 1950. Three Species of Peromyscus. Rood Associates, Santa Barbara, California.
- Eisenberg, JF (1963). "The intraspecific social behavior of some Cricetine rodents of the genus Peromyscus". American Midland Naturalist 69: 240–246. doi:10.2307/2422858.
- Dudley, D. 1973. Paternal behavior in the California mouse (P. californicus) (Thesis) University of California.
- Eisenberg, JF (1962). "Studies on the behavior of Peromyscus maniculatus gambelii and Peromyscus californicus parasiticus". Behavior 19 (3): 177–207. doi:10.1163/156853962X00014.
- Svihla, A (1932). "A comparative life history study of the mice of the genus Peromyscus". Misc. Publ. Mus. Zool. Univ. Michigan 24: 1–39.
- Meserve, PL (1972) Resource and habitat utilization by rodents of the coastal sage scrub community (Thesis) University of California, Irvine.
- Merritt, JF (1974). "Factors influencing the local distribution of Peromyscus californicus in northern California". Journal of Mammalogy 55: 102–114. doi:10.2307/1379260.
- Marten, GG (1973). "Time patterns of Peromyscus activity and their correlations with weather". Journal of Mammalogy 54: 169–188. doi:10.2307/1378878.
- Vestal, EH (1937). "Activities of a weasel at a woodrat colony". Journal of Mammalogy 18: 364.
- Von Bloeker, JC (1937). "Mammal remains from detritus of raptorial birds in California". Journal of Mammalogy 18: 360–361.
Names and Taxonomy
Comments: Smith (1979) examined morphological and electrophoretic variation and retained only two subspecies, californicus in the north and insignis in the south.