Chaetodipus californicus (Merriam, 1889)

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Heteromyidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 170-233 : 213-214

32.

California Pocket Mouse

Chaetodipus californicus

French: Souris-a-abajoues de Californie / German: Kalifornien-Rauhaartaschenmaus / Spanish: Raton de abazones de California

Taxonomy. Perognathus californicus Merriam, 1889 ,

Berkeley, Alameda Co., California, USA.

Based on detailed sequencing of nDNA and mtDNA genes, C. californicus is a close relative of C. fallax , and both are part of the Baja California Peninsula lineage of the “modern” clade of coarse-haired pocket mice, along with C. ammophilus, C. arenarius , C. siccus , and C. spinatus . Eight subspecies recognized.

Subspecies and Distribution. C.c.californicusMerriam,1889—WUSA(SSanFranciscoBay,WCCalifornia).

C.c.bensonivonBloeker,1938—WUSA(SCoastRanges,WCCalifornia).

C.c.bernardinusBenson,1930—SWUSA(SanGabrielandSanBernardinoMts,SWCalifornia).

C.c.disparOsgood,1900—SWUSA(PacificcoastofSWCalifornia).

C.c.femoralisJ.A.Allen,1891—SWUSAandNWMexico(SPacificcoast,SWCalifor-nia,andStoSierraJuarez,NBajaCalifornia).

C.c.marinensisvonBloeker,1938—WUSA(PacificcoastofCCalifornia).

C.c.mesopoliusElliot,1903—NWMexico(SierradeSanPedroMartir,NBajaCalifornia).

C. c. ochrus Osgood, 1904 — W USA (Temblor Range, Tehachapi Mts, and S Sierra Nevada of EC & SC California).

Descriptive notes. Head-body 86-92 mm, tail 103-143 mm, ear mean 13 mm, hindfoot mean 26 mm; weight 18-29 g. There is no significant secondary sexual dimorphism. The California Pocket Mouse is medium-sized to large-sized for the genus, with bicolor, crested, tufted tail that is longer than head-body length. Dorsal pelage is harsh brownish gray, with conspicuous white spines on rump, definite fulvous lateral stripe, and yellowish-white under parts. Chromosomal complement has 2n = 44 and FN = 54. The California Pocket Mouse is elevationally parapatric with its close relative, the San Diego Pocket Mouse ( C. fallax ), which occupies coastal chaparral and desert habitats below denser chaparral habitat favored by the California Pocket Mouse. The California Pocket Mouse is larger, with longer ear and relatively longertail. It is rarely found with other species of coarse-haired pocket mice, but in La Puerta Valley of southern California,it was collected along with the smaller San Diego Pocket Mouse; the Spiny Pocket Mouse ( C. spinatus ), which is smaller and blackish-gray; the Peninsular Pocket Mouse ( C. rudinoris ), which is larger and lacks rump spines; the Long-tailed Pocket Mouse ( C. formosus ), which is smaller and lacks rump spines; and the Desert Pocket Mouse ( C. penicillatus ) which is smaller,lighter in color, lacks rump spines, and restricted to sandy soils.

Habitat. Most commonly associated with dense lowland and montane chaparral below elevations of ¢.1500 m in the Sierra Nevada , Coast, Transverse, and Peninsular ranges of southern California and northern Baja California. The California Pocket Mouse is less common in low-elevation coastal scrub.

Food and Feeding. Diet of the California Pocket Mouse consists largely of seeds of shrubs, annuals, and grasses, but it also includes smaller amounts of green vegetation and insects. Food items are collected in external, furlined cheek pouches and transported back to burrows, where they are stored in burrow caches. It does not need to drink water, subsisting entirely on water from its food and water produced as a byproduct of metabolism.

Breeding. Female California Pocket Mice have 4-5 young/litter after ¢.25 days of gestation. Young are weaned in c.3 weeks and may breed when they are ¢.3 months old.

Activity patterns. The California Pocket Mouse is nocturnal and terrestrial, and it is active throughout the year. Individuals may become torpid for 10-14 hours during the day when food is scarce (regardless of the season), and surface activity is reduced or absent during cold or wet weather, which might indicate an extended period of torpor.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Aquino & Neiswenter (2014), Best (1993a), Ceballos & Oliva (2005), Linzey, Timm, Alvarez-Castaneda, Castro-Arellano & Lacher (2008i), Williams (1999c), Williams etal. (1993).

Figures

27. Hispid Pocket Mouse (Chaetodipus hispidus), 28. Long-tailed Pocket Mouse (Chacetodipus formosus), 29. Bailey's Pocket Mouse (Chaetodipus bailey), 30. Peninsular Pocket Mouse (Chaetodipus rudinoris), 31. Spiny Pocket Mouse (Chaetodipus spinatus), 32. California Pocket Mouse (Chaetodipus californicus), 33. San Diego Pocket Mouse (Chaetodipus fallax), 34. Little Desert Pocket Mouse (Chaetodipus arenarius), 35. Dalquest’s Pocket Mouse (Chaetodipus ammophilus), 36. Cerralvo Island Pocket Mouse (Chaetodipus siccus), 37. Desert Pocket Mouse (Chaetodipus penicillatus), 38. Chihuahuan Desert Pocket Mouse (Chaetodipus eremicus), 39. Sinaloan Pocket Mouse (Chaetodipus pernix), 40. Rock Pocket Mouse (Chaetodipus intermedius), 41. Nelson’s Pocket Mouse (Chaetodipus nelsoni), 42. Lined Pocket Mouse (Chaetodipus lineatus), 43. Goldman’s Pocket Mouse (Chaetodipus goldmani), 44. Narrow-skulled Pocket Mouse (Chaetodipus artus)

Subspecies and Distribution. C.c.californicusMerriam,1889—WUSA(SSanFranciscoBay,WCCalifornia). C.c.bensonivonBloeker,1938—WUSA(SCoastRanges,WCCalifornia). C.c.bernardinusBenson,1930—SWUSA(SanGabrielandSanBernardinoMts,SWCalifornia). C.c.disparOsgood,1900—SWUSA(PacificcoastofSWCalifornia). C.c.femoralisJ.A.Allen,1891—SWUSAandNWMexico(SPacificcoast,SWCalifor-nia,andStoSierraJuarez,NBajaCalifornia). C.c.marinensisvonBloeker,1938—WUSA(PacificcoastofCCalifornia). C.c.mesopoliusElliot,1903—NWMexico(SierradeSanPedroMartir,NBajaCalifornia). C. c. ochrus Osgood, 1904 — W USA (Temblor Range, Tehachapi Mts, and S Sierra Nevada of EC & SC California).