53. San Quintin Kangaroo Rat Dipodomys gravipes French: Rat-kangourou de San Quintin / German: Baja-California-Kangururatte / Spanish: Rata canguro de San Quintin Taxonomy. Dipodomys gravipes Huey, 1925, 2 mi. [3 km] W Santo Domingo Mission, 30°45°N, 115°58’W, Baja California, Mexico. Based on molecular sequence analyses, D. gravipesis a member of the heermanni species group, along with D. heermanni, D. panamintinus, D. microps, D. ingens, and D. stephensi, which it most resembles. Monotypic. Distribution. NW Mexico (restricted area along the coastal plains in NW Baja California). Descriptive notes. Head—-body 129-132 mm (males) and 126-130 mm (females), tail 168-180 mm, ear 11-16 mm, hindfoot 44-45 mm; weight (means in two populations) 81 g and 91 g (males) and 79 g and 85 g (females). Male San Quintin Kangaroo Rats are slightly larger than females. This is a relatively large, heavy-bodied kangaroo rat with small ears, five toes on hindfeet (including small claw on side of hindfoot), small auditory bullae, and wide skull. Upper parts are pinkish buff; tail is bicolored, with broad dark dorsal and ventralstripes and dark tuft. Chromosomal complement 2n = 70 and FN = 71. The San Quintin Kangaroo Rat is larger than two sympatric species: Merriam’s Kangaroo Rat (D. merriami) lacks vestigialfifth toe on hindfoot, and the Dulzura Kangaroo Rat (D. simulans) has longer ears, shorter hindfeet, smaller body size, and thinner, darker, and more sharply bicolored tail. Habitat. Very small area of the California coastal scrub along the northern Pacific coast of Baja California, from San Telmo south to El Rosario, extending from sea level to an elevation of ¢.30 m and ¢.20 km inland from the coast. The initial record described habitat of the San Quintin Kangaroo Rat as “cactus covered slopes” at the mouth of the Santo Domingo River. In the north, populations occurred on flat areas of the San Quintin Plains with short vegetation. Southern populations inhabited the flat floodplain of the Arroyo del Rosario, an area bordered by mesas and hills. The Agile Kangaroo Rat (D. agilis) inhabits higher, densely vegetated areas. This pattern of habitat separation is similar to that of Stephens’s Kangaroo Rat (D. stephensi) and the Agile Kangaroo Rat in southern California. Burrows were not located under vegetation and, except in one instance, did not have mound-like formations. Burrows had an average of five openings per system; tunnels went to a depth of ¢.50 cm; and an average of three nests and ten food caches were located about halfway down to the greatest depth. Food and Feeding. There is no information available for this species. Breeding. There is no specific information available for this species, but age of specimens implies that breeding occurs during several months of the year, with peaks in winter and spring. Activity patterns. There is no information available for this species. Movements, Home range and Social organization. There is no information available for this species. Status and Conservation. Classified as Critically Endangered on The IUCN Red List. The San Quintin Kangaroo Rat has an affinity for deep soils in relatively flat areas and a lack of tolerance for cultivation. Extensive agricultural development has destroyed much of its former habitat. In the early 1970s, populations of San Quintin Kangaroo Rats were found at three locations, and the last population was found in 1986. It might be extinct. Bibliography. Alexander & Riddle (2005), Alvarez-Castaneda, Castro-Arellano & Lacher (2008a), Best (1993a, 1993b), Best & Lackey (1985), Ceballos & Oliva (2005), Eisenberg (1963, 1993), Jones (1993), Hall (1981), Patton & Rogers (1993), Williams et al. (1993).

Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Heteromyidae, pp. 170-233 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 225-226, DOI: 10.5281/zenodo.6611160