Communication signals include the growl, squawl, and low grunt. Other forms of auditory communication include tooth-chattering and foot-drumming. Scent marking is also used. Touching is a highly used signal during mating. These animals perceive their environment through visual, tactile, acoustic, and chemical channels.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no adverse effects of San Joaquin pocket mice on humans.
San Joaquin pocket mice are important members of native ecosystems and their predation on insects may impact agricultural pests.
Little is known about the ecosystem role of San Joaquin pocket mice because of extensive loss of their natural habitat. They are prey for their predators and they are themselves predators of small invertebrates. They may disperse seeds and help aerate the soil through burrowing.
Ecosystem Impact: disperses seeds; soil aeration
San Joaquin pocket mice are mainly granivorous, eating seeds of annual and perennial grasses, shrubs, and forbs. They will also eat soft-bodied insects, cutworms, earthworms, and even grasshoppers. In captivity they have been known to eat a mixture of parakeet seeds, rolled oats, sunflower seeds, and small amounts of leaves. Seeds and oats have been used to catch these animals live. They transport and store their food in fur-lined pockets in their cheeks.
Animal Foods: insects; terrestrial worms
Plant Foods: seeds, grains, and nuts
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Granivore )
San Joaquin pocket mice are found in California's central valleys, including the San Joaquin, Sacramento, and Salinas valleys, as well as the surrounding foothills of the western Sierra Nevada mountains and the western Mojave desert.
Biogeographic Regions: nearctic (Native )
San Joaquin pocket mice are found in open grasslands, savanna, and desert shrub communities. They are most abundant in uncultivated areas and often live in areas with sandy washes and finely textured soils. Agriculture and urban development have displaced San Joaquin pocket mice from much of their native habitat.
Range elevation: 350 to 600 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland
San Joaquin pocket mice have been observed living up to 10 years. Most probably live only one to a few years and most mortality probably occurs when individuals are less than 1 year old.
San Joaquin pocket mice have silky pelage without bristles and spines. The dorsal pelage is pale to pinkish, overlaid with blackish brown hairs. The ventral pelage is white and there are orange markings around the eyes. The tail, which is slightly larger than 50% of the total length, is bi-colored and relatively non-penicillate. Tail hairs extend less than 6 mm beyond the end of the tail. The antitragus of the ear is unlobed. San Joaquin pocket mice get their name from the fur-lined pockets in their cheeks that are used to store and transport seeds. Subspecies of P. inornatus differ in size of body, length of tail, coloration, and skull characteristics.
Range mass: 7 to 12 g.
Range length: 130 to 149 mm.
Other Physical Features: endothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: male larger
San Joaquin pocket mice are preyed on by birds of prey, foxes, snakes, and feral cats. They are similar in color to their sandy surroundings, making it difficult for predators to see them. They are vigilant and seek safety when they detect a predator and are active at night to minimize their detection by predators. Through habitat destruction and the use of rodenticides, humans are the biggest threat to this species currently.
Known Predators:
Anti-predator Adaptations: cryptic
During estrus, females are involved in rushing, chasing, fighting, sunbathing, marking, digging, kicking, naso-anal contact, grooming, mounting, and escape leaping. Interaction between the sexes changes as the female passes through estrus. Mating involves one bout of mounting, afterwards the female twists onto her side and throws the male off. It is likely that males and females have multiple mates, but there is little information on the mating strategy.
Mating System: polygynandrous (promiscuous)
The breeding season occurs from March to July, with the female having at least 2 litters of 4 to 6 offspring per year. The estrus cycle is 5 to 6 days in length.
Breeding interval: Females have at least two litters per breeding season.
Breeding season: San Joaquin pocket mice breed between March and July.
Range number of offspring: 4 to 6.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
The young are born in a burrow near the base of shrubs. They remain in the birthing den until mature. The length of time to maturity is unknown. Females invest heavily in offspring through gestation and lactation. Males are unlikely to contribute to offspring care.
Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
The San Joaquin pocket mouse or Salinas pocket mouse (Perognathus inornatus) is a species of rodent in the family Heteromyidae. It is endemic to California in the United States where it lives in desert and semi-desert habitats.
Pocket mice can be distinguished from similar small rodents by their externally opening fur-lined cheek pouches. They differ from kangaroo mice in not having the soles of the feet entirely covered in fur. Kangaroo rats have fur-lined pockets, but they are larger, and have a dark stripe across the hips and dark stripes on both the top and bottom surfaces of the tail.[2]
The San Joaquin pocket mouse has a total length of about 128 to 160 mm (5.0 to 6.3 in), including a tail of 65 to 78 mm (2.6 to 3.1 in). The tail has a short tuft of hairs at its tip. The fur on the head and body is short and soft, without spines or bristles. The colour is buff, and there is sometimes a pale patch at the base of the small rounded ears. The tail is identically coloured on its upper and lower surfaces.[2]
This pocket mouse is endemic to California in the United States. It is found in the Tehachapi Mountains and the lower slopes of the western Sierra Nevada at elevations of up to 600 m (2,000 ft). It also occurs in the upper Sacramento Valley, the San Joaquin Valley and the Salinas Valley, and southwards to the Mojave Desert.[1] It occurs in the "Upper Sonoran life zone", characterized by grassland and semi-desert vegetation, and the "Lower Sonoran life zone", hot desert with creosote bush and Joshua tree.[3]
The San Joaquin pocket mouse feeds on seeds of grasses and various plants, carrying them back to its burrow in its cheek pouches.[1] It may also eat soft-bodied invertebrates. It stores seeds surplus to its immediate requirements in chambers in the burrow for use at times of year when food is scarce. It may become torpid in winter. Breeding takes place between March and July, and there may be two or more litters of four to six young per year.[1]
P. inornatus has a wide range and is common in suitable habitats within that range. It seems to be secure within its range, and no particular threats have been identified except in the north, where agricultural development is destroying and fragmenting its habitat. The International Union for Conservation of Nature has listed its conservation status as being of "least concern".[1]
The San Joaquin pocket mouse or Salinas pocket mouse (Perognathus inornatus) is a species of rodent in the family Heteromyidae. It is endemic to California in the United States where it lives in desert and semi-desert habitats.
