Shrub rabbit
| Shrub rabbit | ||||||||||||
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Shrub Rabbit ( Sylvilagus bachmani ) |
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| Sylvilagus bachmani | ||||||||||||
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The brush rabbit ( Sylvilagus bachmani ) is a mammalian species in the genus of cottontail rabbit in the leporidae . It lives along the American Pacific coast up to the Baja California peninsula and occurs mainly in dense shrub stands. The first descriptor George Robert Waterhouse named the species after the priest and naturalist John Bachman
It is one of the smallest species in the genus with short legs and comparatively short ears. The species is not endangered, even if individual subspecies may be threatened.
features
The shrub rabbit is one of the smallest species of the genus with a body weight of less than 1000 grams and a height of 30.0 to 37.5 centimeters. The tail length is 10 to 30 millimeters, the ear length 50 to 60 millimeters and the hind foot length 71 to 86 millimeters. The females are usually slightly larger than the males. The back color and the tail are gray-brown to dark brown, the belly side and the underside of the tail are colored whitish. The tail, ears and legs are relatively short, the feet are narrow and short and only slightly hairy. The ears are slightly pointed and are not rounded. The vibrissae are black.
The karyotype of the shrub rabbit consists of a diploid chromosome set of 2n = 48 chromosomes. Besides the San José shrub rabbit ( S. mansuetus ), which is directly descended from it, it is the only species to have this karytype, which is regarded as a basic characteristic for the genus.
distribution
The habitat of the shrub rabbit stretches along the American Pacific coast from the Columbia River to the south via Oregon and California to Baja California . It stretches along the Chaparral , the eastern limit of the distribution area is formed by the western foothills of the Sierra Nevada . The species also occurs on the offshore islands of Año Nuevo Island and San Jose off the California coast .
The species mainly colonizes densely overgrown , shrubby habitats such as Rubus populations.
Way of life
The shrub rabbit needs very dense shrub stands of the chaparral as a habitat that offer it protection. The individual action areas are very small and are less than 2,000 m². The bushes contain passages that the animals use as paths, as well as animal structures that the rabbits use but do not dig themselves. For grazing, they move very carefully out of the bushes. Their diet consists mainly of grasses, with other plant components such as leaves and berries added seasonally. The most important food crops include goose thistles ( Sonchus ) and Dudleya , especially Dudleya farinosa . Unlike most hares, they are able to climb low shrubs or trees.
The mating season varies from region to region and depends on temperatures and other factors. In northern Oregon, it usually begins in February and ends in August; in California, it lasts from December to May or June. The litters averaged 2.8 pups in Oregon and 3.5 to 4.0 in California. Each year the females give birth to around 15 young animals in five to six litters with a gestation period of 27 days per litter.
Systematics
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Relationship of the basal cottontail rabbits
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The shrub rabbit is assigned as an independent species to the cottontail rabbit (genus Sylvilagus ), which consists of around 20 species. The species was first described scientifically in 1839 by the British zoologist George Robert Waterhouse as Lepus bachmani , who named it after the naturalist and Lutheran priest John Bachman .
Sometimes the shrub rabbit was combined with the dwarf rabbit ( Brachylagus idahoensis ) to form a subgenus Microlagus within the cottontail rabbit, but today it is regarded as a basal species and the dwarf rabbit as a sister species of the genus. The San José shrub rabbit ( S. mansuetus ) comes directly from the shrub rabbit as an island form and is the only species besides this to have the karyotype of 2n = 48 chromosomes, which is regarded as a basic characteristic, which it shares with the real rabbit (genus Lepus ) and the volcanic rabbit ( Romerolagus diazi ) share. Due to the small genetic differences, the San José shrub rabbit is sometimes also regarded as a subspecies of the shrub rabbit. Current studies place it as a sister group of the S. b. cerrosensis from Isla de Cedros .
Depending on the source, up to 13 subspecies of the shrub rabbit have been described, but the delimitation of the subspecies from one another is described as difficult due to the often sparse initial descriptions on the basis of fewer external characteristics and on the basis of fewer individuals. It is unclear whether these are actually true subspecies or whether some of them were only described as subspecies due to individual variations, age-related characteristics or for other reasons; the internal system is accordingly being discussed. The following 13 subspecies are currently considered valid:
- Sylvilagus bachmani bachmani Waterhouse, 1839 : nominate form, occurs in the southern part of the coastal areas in central and western California.
- S. b. cerrosensis Allen , 1898 : occurs on Isla de Cedros , Baja California in northwest Mexico.
- S. b. cinerascens Allen, 1890 : occurs in southwestern California.
- S. b. exiguus Nelson , 1907 : comes in the southern Baja California , Baja California before.
- S. b. howelli Huey , 1927 : occurs in northeast Baja California.
- S. b. macrorhinus Orr , 1935 : occurs in the eastern part of central and western California.
- S. b. mariposae Grinnell & Storer , 1916 : occurs in the northern part of central California.
- S. b. peninsularis Allen, 1898 : found in Baja California Sur in southern Baja California , Mexico.
- S. b. riparius Orr, 1935 : occurs in the western part of central California.
- S. b. rosaphagus Huey, 1940 : found in northwest Baja California.
- S. b. tehamae Orr, 1935 : occurs in northwest Oregon on the southern Columbia River and northwest California.
- S. b. ubericolor Miller , 1899 : occurs in western Oregon on the southern Columbia River and in northwestern California.
- S. b. virgulti Dice, 1926 : occurs in parts of central and western California.
Hazard and protection
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The shrub rabbit is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as not endangered (least concern) due to the size of the population and the large distribution area.
No decline is known for most populations of the species, the subspecies S. b. However, riparius is classified as endangered by the state of California and the US Fish and Wildlife Service due to increasing habitat changes and the threat of forest fires and floods . It occurs exclusively in the Caswell Memorial State Park on the Stanislaus River and in the area of the southern delta of the San Joaquin River .
supporting documents
- ↑ a b c d E.W. Jameson Jr., Hans J. Peeters: Mammals of California. California Natural History Guides, University of California Press, 2004; Pp. 365-366. ISBN 0-520-23582-7 .
- ↑ a b c d e Joseph A. Chapman, John EC Flux (Ed.): Rabbits, Hares and Pikas. Status Survey and Conservation Action Plan. (PDF file; 10.74 MB) International Union for Conservation of Nature and Natural Resources (IUCN), Gland 1990; P. 99. ISBN 2-8317-0019-1 .
- ^ Joseph A. Chapman: Sylvilagus bachmani. Mammalian Species 34, 1974; Pp. 1-4. doi : 10.2307 / 3503777
- ↑ a b c d e f A.A. Lissovsky: Brush Rabbit - Sylvielagus bachmani. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6), Lynx Edicions, Barcelona 2016; Pp. 114-115. ISBN 978-84-941892-3-4 .
- ↑ a b c d Sylvilagus bachmani in the endangered Red List species the IUCN 2019. Posted by: PA Kelly, C. Lorenzo, ST Alvarez-Castaneda, 2018. Retrieved on June 20 of 2019.
- ↑ Sergio Ticul Álvarez-Castañeda, Consuelo Lorenzo: Genetic evidence supports Sylvilagus mansuetus (Lagomorpha: Leporidae) as a subspecies of S. bachmani. Zootaxa 4196 (2), 2016; Pp. 289-295. doi : 10.11646 / zootaxa.4196.2.7
- ^ A b c Robert T. Orr : Descriptions of three new races of brush rabbit from California. Proceedings of the Biological Society of Washington 48, 1935; Pp. 27-30. ( Digitized version )
literature
- Joseph A. Chapman, John EC Flux (Eds.): Rabbits, Hares and Pikas. Status Survey and Conservation Action Plan. (PDF file; 10.74 MB) International Union for Conservation of Nature and Natural Resources (IUCN), Gland 1990; P. 99. ISBN 2-8317-0019-1 .
- Joseph A. Chapman: Sylvilagus bachmani . In: Mammalian Species . tape 34 , 1974, p. 1–4 ( full text (PDF file; 372 kB)).
- AA Lissovsky: Brush Rabbit - Sylvielagus bachmani. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6), Lynx Edicions, Barcelona 2016; Pp. 114-115. ISBN 978-84-941892-3-4
Web links
- Sylvilagus bachmani in the endangered Red List species the IUCN 2019. Posted by: PA Kelly, C. Lorenzo, ST Alvarez-Castaneda, 2018. Retrieved on June 20 of 2019.