Dipodomys agilis, Gambel, 1848
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publication ID |
https://doi.org/ 10.5281/zenodo.6611160 |
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DOI |
https://doi.org/10.5281/zenodo.6608114 |
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persistent identifier |
https://treatment.plazi.org/id/3C3D87A6-876B-B131-1B03-5211F68EFC4A |
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treatment provided by |
Carolina |
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Dipodomys agilis |
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59. View Plate 11: Heteromyidae
Agile Kangaroo Rat
French: Rat-kangourou agile / German: Pazifik-Kangururatte / Spanish: Rata canguro & gil
Other common names: Nimble Kangaroo Rat, Pacific Kangaroo Rat
Taxonomy. Dipodomys agilis Gambel, 1848 View in CoL ,
Los Angeles, Los Angeles Co., California, USA.
Based on molecular sequence analyses, D. agilis is a member of the agilis species group, along with D. simulans and D. venustus. Dipodomys simulans , formerly included in this species, was found to differ karyotypically (different 2n), allozymically, morphologically (external, cranial, and bacular characters), and ecologically, and the two species are probably sympatric in Cajon Pass, separating the San Gabriel and San Bernardino mountains. Other likely formersites of sympatry have probably been engulfed by urban development. Two subspecies recognized.
Subspecies and Distribution.
D. a. perplexus Merriam, 1907 — SW USA (S Sierra Nevada, Tehachapi , and San Gabriel Mts, N San Fernando Valley of SW California ). View Figure
Descriptive notes. Head—body 115-125 mm (males) and 107-113 mm (females), tail 170-195 mm (males) and 170-192 mm (females), ear 13-15 mm, hindfoot 40-46 mm; weight 66-79 g (males) and 63-78 g (females). Male Agile Kangaroo Rats are slightly larger than females. Tail is 155% of head—body length. This is a medium-sized kangaroo rat with large ears, five toes on hindfeet (including small claw on side of hindfoot), and narrow skull. Upper parts are dark reddish brown or dusky cinnamon buff; tail is bicolored, with dull brownish-black crest and tuft.Juveniles have a darker pelage than adults and lack elongated crests of hairs on their tails. Chromosomal complement is 2n = 62 and FN = 110-116. The Agile Kangaroo Rat is most similar to the Dulzura Kangaroo Rat ( D. simulans ) that is smaller with smaller ears and narrower face; the Narrow-faced Kangaroo Rat ( D. venustus ) that is larger with longer ears and narrower face; and Heermann’s Kangaroo Rat ( D. heermanni ) that is larger with smaller ears and widerface) Habitat. Primarily open woodland and chaparral communities of foothills of Transverse Ranges of west-central California at elevations of 500-2250 m. The Agile Kangaroo Rat is most commonly found in open chaparral and coastal sage communities and is most abundant in level tracts of coastal sage. Its limited digging ability restricts it to areas of loose soils, such as sandy areas within chaparral. It does not occur where ground is covered with plant debris, as in heavy chaparral with scrub oak ( Quercus , Fagaceae ) and lilac ( Ceanothus , Rhamnaceae ). The Agile Kangaroo Rat often burrows within and along arroyos, and large colonies occur locally on sandy soils adjacent to large washes. Species of rodents co-occurring with the Agile Kangaroo Rat include the California Ground Squirrel (Otospermophilus beecheyt), Botta’s Pocket Gopher ( Thomomys bottae), the California Pocket Mouse ( Chaetodipus californicus ), Merriam’s Kangaroo Rat ( Dipodomys merriami ), Stephens’s Kangaroo Rat ( D. stephensi ), the Dusky-footed Woodrat (Neotoma fuscipes), and the California Deermouse (Peromyscus californicus ). Coyotes (Canis latrans) excavate burrow systems and are major predators, along with western rattlesnakes (Crotalus viridis), great horned owls (Bubo virginianus), Bobcats (Lynx rufus), and Northern Gray Foxes (Urocyon cinereoargenteus).
Food and Feeding. Diet of the Agile Kangaroo contains seeds of forbs, grasses, and shrubs, including laurel sumac ( Rhus laurina, Anacardiaceae ) and chamise ( Adenostoma , Rosaceae ), scrub oak acorns, and juniper ( Juniperus , Cupressaceae ) berries. Insects are also eaten. One juvenile had c.550 seeds of bromegrass ( Bromus , Poaceae ) stuffed into its cheek pouches. One excavated burrow was oval in cross-section, c¢.5 cm in diameter, sloping gently from entrance to main burrow c.20 cm belowground for 2:5 m, then c.0-5 m deep for another 2 m, where led to another entrance under a small perennial plant. There were six branches in the burrow, each terminating in an enlarged chamber. A nest of hulls of grass seeds was in one chamber; other chambers, usually closed with a plug of earth, contained stored acorns, grass seeds, and parts of flowers. Closed storage chambers held 29-149 acorns.
Breeding. Breeding season of the Agile Kangaroo Rat occurs in March—July, although some litters may be born in autumn. Averagelitter sizes are 2-3 young (range 2-4).
Activity patterns. During nocturnal foraging, Agile Kangaroo Rats can harvest large amounts of seeds: in experiments, one 58-g individual moved c.300 g of sunflower ( Helianthus annuus, Asteraceae ) seeds in one night. Burrow opening is sometimes plugged during the day. Experiments indicate that Agile Kangaroo Ratis an excellent swimmer.
Movements, Home range and Social organization. Densities of Agile Kangaroo Rats were 5-15 ind/ha occur in pinyon-juniper habitat from mid-September to mid-March, but densities can range from 6 ind/ha to 232 ind/ha. Populations increase after fires that create open space.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Populations of the Agile Kangaroo Rat in the Los Angeles Basin and foothills of the San Gabriel and San Bernardino mountains have been extirpated, and others are likely decreasing due to urbanization and related habitat destruction.
Bibliography. Alexander & Riddle (2005), Best (1993a, 1999b), Best et al. (1986), Eisenberg (1963, 1993), Hafner et al. (2007), Hall (1981), Ingles (1954), Jones (1993), Linzey & NatureServe (Hammerson) (2008a), Patton & Rogers (1993), Price & Waser (1984), Sullivan & Best (1997), Williams et al. (1993).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
