Lepus callotis, Wagler, 1830
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publication ID |
https://doi.org/ 10.5281/zenodo.6625539 |
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DOI |
https://doi.org/10.5281/zenodo.6625472 |
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persistent identifier |
https://treatment.plazi.org/id/03822308-B767-FFD8-FAF6-F8A1FE10FDCD |
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Carolina |
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scientific name |
Lepus callotis |
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50. View On
White-sided Jackrabbit
French: Lievre du Mexique / German: \Weil3flankenhase / Spanish: Liebre de flancos blancos
Other common names: Beautiful-eared Jackrabbit, Gaillard Jackrabbit, Snow Sides
Taxonomy. Lepus callotis Wagler, 1830 View in CoL ,
“Mexico.” Restricted by E. W. Nelson in 1909 to the “southern end of the Mexican Tableland.”
Morphological characteristics showed only partial separation between Mexican subspecies of L. callotis and L. californicus , whereas nearly complete separation between L. callotis and L. flavigularis was apparent. A recent molecular phylogenetic study supports another theory suggesting that L. californicus might have been isolated in Mexico and diverged into a new linage. From original stock ( L. callotis ), one population was isolated in western coastal plains (L. allen?) and a second population became isolated in the Isthmus of Tehuantepec ( L. flavigularis ). As taxonomists are still trying to clarify the species differentiation in Lepus , the subspecific taxonomy is not elaborated yet. The original descriptions of the subspecies are often not very helpful as they are mostly based on few exterior characteristics and small numbers of individuals. It has been shown that the variability is clinal in more careful investigations. Hence, the distinction in subspecies might be arbitrary and unreasonable. Distribution of L. callotis is allopatric with L. alleni to which it is probably related, parapatric with L. flavigularis , and sympatric with Sylvilagus cunicularius . This species and L. californicus are only sympatric in marginal habitats because they typically occupy different habitat types. Two subspecies recognized.
Subspecies and Distribution.
L. c. gaillardi Mearns, 1896 — SW USA (extreme SW New Mexico) and discontinuously in NC Mexico (NW Chihuaha, SC Chihuahua, and NC Durango N of the Rio Nazas). View Figure
Descriptive notes. Head—body 430-600 mm, tail 47-92 mm, ear 110-160 mm, hindfoot 118-141 mm; weight 1.5-3.2 kg. The White-sided Jackrabbit is medium-sized, with relatively short hindfeet and long ears. Dorsal pelage is pale ocherous cinnamon, mixed with black. Sides, rump, thighs, limbs, and ventral fur are white. Rump is divided by black medial line. Gular patch is bufty, becoming ocherous on fronts of shoulders and sides of neck. Head is cream-buff, mixed with black, and eye rings are whitish. Nape is ocherous buff. Ears are scantily covered with short hairs but are almost bare at their concave surfaces. Tail is white below and black above. Female White-sided Jackrabbits are larger and heavier than males. Geographical variation in pelage color exists, with paler individuals in Chihuahua. The two subspecies also vary in pelage color: callotis has blackish tint and black nape patch, and gaillardi has pale buff tint and brown nape. White-sided Jackrabbits molt twice a year.
Habitat. Grassy open plains with little shrub cover and desert-grassland of tobosa grass ( Hilaria mutica , Poaceae ). White-sided Jackrabbits avoid hilly areas. A study showed that 97-1% of occupied habitat was grassland, and remaining non-grass habitat was adjacent to large expenses of grassland habitat. The White-sided Jackrabbitis an animal of open grassland, whereas the Black-tailed Jackrabbit ( L. californicus ) inhabits vegetation where forbs and shrubs are dominant, so overgrazing and grassland deterioration favorsthe latter species and reducesdistribution of the former. White-sidedJackrabbits occur at elevations of 1350-2100 m in north-western Chihuahua, ¢.2550 m in northern Puebla, and ¢.750 m in Morelos.
Food and Feeding. Diets of White-sided Jackrabbits typically contain more than 99% grass. Plants eaten were true grasses ( Poaceae ) such as buffalograss ( Bouteloua dactyloides), tobosa grass, wolftail ( Lycurus sp. ), blue grama (B. gracilis), and vine mesquite ( Panicum obtusum) and sedge nutgrass ( Cyperus rotundus, Cyperaceae ), ring muhly ( Muhlenbergia torreyi), and fiddleneck ( Amsinckia sp. , Boraginaceae ), woolly Indian wheat ( Plantago purshii, Plantaginaceae ), and Wright buckwheat ( Eriogonum wrightii, Polygonaceae ). The White-sided Jackrabbit uses its forepaws to excavate bulbous tubers of young nutgrass (C. rotundus) in the dry season.
Breeding. Reproductive season of the White-sidedJackrabbit minimally lasts from mid-April to mid-August but may extend from mid-March until mid-October. Litters have 1-4 young, with an average of 2-2 young. Females can produce at least three litters per year. Newborns have soft and woolly fur and are typically born in burrows.
Activity patterns. Most activity of the White-sided Jackrabbit occurred between 22:00 h and 05:00 h in New Mexico, whereas it was usually seen in the early morning or at dusk in Zacatecas, Mexico. Cloud cover, precipitation, and wind limited activities, but temperature had little effect.
Movements, Home range and Social organization. When predators alarm Whitesided Jackrabbits, they alternately flash their white sides while running away or leap straight upward while extending their hindlegs and flashing their white sides. They construct and use shelter forms that are predominantly located in dense stands of clumped tabosa grass. Occasionally but rarely, underground shelters are used. Home ranges of White-sided Jackrabbits overlap, and individuals will move at least 1-6 km to feed. White-sided Jackrabbits usually occur in male-female pairs. This pair bond is most evident during the reproductive season. The male defends the pair from intruding males. It is suggested that pair bonding keeps sexes together during the breeding season because densities are low. White-sided Jackrabbits use three types of vocalization. One is an alarm or fear reaction and consists of a high-pitched scream. The second are harsh grunts produced by the male of a pair to chase away an intruding male. The third is a trilling grunt emitted by an animal of unknown sex during a sexual chase.
Status and Conservation. Classified as Near Threatened on The IUCN Red List. The White-sided Jackrabbit is widespread but has been reported as rare throughoutits distribution. Information is lacking regarding current population status in Mexico—the main part of its distribution. Population declines have been reported in New Mexico and Durango, Mexico. A major threat to the White-sided Jackrabbit is the loss of grassland habitat due to an increase of livestock grazing, which provides better habitat for the highly adaptable Black-tailed Jackrabbit. Prospects for survival of the White-sided Jackrabbit in many parts of its distribution are poor. Additional threats are hunting for local subsistence, predation by introduced species, competition with livestock, habitat fragmentation, and human-induced fires. A model generated for predicted climate conditions in 2050 indicated a 60% reduction of the current distribution of the White-sided Jackrabbit. Its distribution in the USA is restricted to two valleys of only c.120 km? in southern Hidalgo County, New Mexico, and it has been listed as threatened by the New Mexico Department of Game and Fish. More data are needed on population status of the White-sided Jackrabbit.
Bibliography. AMCELA, Romero & Rangel (2008i), Anderson (1972), Anderson & Gaunt (1962), Angermann (2016), Baker (1977), Baker & Greer (1962), Bednarz & Cook (1984), Best & Henry (1993b), Bogan & Jones (1975), Dalguest (1953), Davis & Lukens (1958), Davis & Russell (1953), Desmond (2004), Dixon et al. (1983), Dunn et al. (1982), Findley (1987), Findley & Claire (1977), Flux & Angermann (1990), Goldman & Moore (1945), Hall (1981), Hoffmann & Smith (2005), Hoffmeister (1986), Lissovsky (2016), Mearns (1896b), Nelson (1909), Ramirez-Silva et al. (2010).
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