Long-tailed Chinchilla
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| Long-tailed Chinchilla | ||||||||||||||
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| Chinchilla lanigera Bennett, 1829 |
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Mus laniger |
The long-tailed chinchilla (Chinchilla lanigera), also called the Chilean, Coastal, or Lesser chinchilla, is one of two species of rodents from the genus Chinchilla, the other species being Chinchilla brevicaudata. Wild populations of C. lanigera occur in Aucó, near Illapel, IV Región, Chile (31°38’S, 71°06’W), in Reserva Nacional Las Chinchillas and in La Higuera, ca. 100 km north of Coquimbo (29°33’S, 71°04’W) [1] Chilean chinchillas were reported from Talca (35°30’S), Chile, reaching north to Peru [2] and eastward from Chilean coastal hills throughout low mountains. By the mid-19th century, Chilean chinchillas were not found south of the Choapa river.
No fossils are known.
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[edit] Characteristics
Chinchilla lanigera is smaller than Chinchilla brevicaudata, wild animals have body length up to 260 mm. It has more rounded ears 45 mm in length and longer tail (up to 130 mm compared to 100 mm in Chinchilla brevicaudata). Number of caudal vertebrae is 23 in Chinchilla lanigera (20 in Chinchilla brevicaudata). Average males weight 369–493 g (mean: 412 g) and females weigh 379-450 g (mean: 422 g). [3] Domestic animals are larger than wild ones and more sexually dimorphic with the female weighing up to 800 g and males up to 600 g.
The word “lanigera” translates into “bearing a woolen coat”, yet chinchillas do not have a woolen coat, but instead one consisting of hair. Hair is 2–4 cm long, with gray, white, and black bands; it is silky, extremely soft, and firmly adhered to skin. [2] Up to 75 wool hairs, 5–11 mm in diameter, emerge together from a single skin pore. Vibrissae are abundant, strong, long (100– 130 mm), and emerge from single follicles[4]. General color of upper parts is bluish or silvery gray, underparts are yellowish white. Tail has long, coarse, gray and black hairs on its dorsal surface that are 30–40 mm long near the body, 50–60 mm long near the tip, and form a bristly tuft that exceeds vertebrae by 50 mm[2]
Gestation in captivity is 111 days (range, 105–118 days). Litter size is usually 2 or 3 (mean: 1.75. Sex ratio at birth (male : female) was 1.10 – 1.20. Mean neonatal mass in captivity is 52 g (range, 50–70). Mean mass of newborn litter is 83.3 g; individual mass is inversely related to litter size. Mortality at birth: 10.4%.
In the wild they breed in Oct-Dec, which is summer.
All neonates are precocial, fully furred, with erupted teeth, open eyes, and able to walk within an hour after birth. They begin to take solid foods at 1 week of age, however lactation normally lasts 6–8 weeks in captivity, and the minimal period of suckling necessary for survival is 25 days. Growth rate is 3.6 g/day during the 1st month, decreasing to 1.56 g/day from 2 to 6 months, and to 0.65 from 6 to 12 months.
Sexual maturity in both sexes occurs on average at 8 months, but may occur as early as 5.5 months. Maximum recorded life span in the wild is 6 years. A few captives have lived 20, and some have bred at 15 years[3].
[edit] Varieties
Three different types of C.lanigera are commonly recognized[5]
1) The La Plata Type has better developed musculature and heavier bone structure than the other two types. They look more roundish or compact, with short, wide head, large distance from one ear to another, a relatively straight dorsal line. The shoulders are often as wide as the chest and rump. The ears are short and nearly round.
2) The Costina Type is weaker in musculature and bone structure with the most distinctive feature being the longer hind legs. The fore legs are shorter, placed closer together, and the shoulders are narrower. The vertebral column is more arched, the neck line sometimes very deep, forming a slight hump on the back of the animal. When viewed directly from the front, the head has a V-shape, the nose is pointed, and the distance between the ears is rather wide. The ears are long and positioned at an angle of about 45 degrees.
3) The Raton Type is reminiscent to the La Plata type in its body structure. The nose is pointed as in Costina and the ears are positioned very close together and rather horizontal. Animals are distinctively smaller.
[edit] Ecology
The natural habitat of Chinchilla lanigera is barren, arid, and rugged areas of transverse mountain chains in north-central Chile that connect the coastal mountain ranges to the Andes with elevations from 400 to 2,000 m. Climate is rather harsh with summer temperatures climbing during the day to up to 30°C in a shade and dropping to 7°C at night (or below freezing point in winter).
Typical habitat is rocky or sandy with a sparse cover of thorn shrubs, few herbs and forbs, scattered cacti, and patches of succulent bromeliads toward the coast. Wild Chilean chinchillas feed on up to 24 plant species, mainly herbs and grasses. Diet changes between sites both seasonally and across years. They consume succulents in summer and appear to drink no water in the wild.
Chinchilla lanigera is social. Colonies of ca. 100 individuals are usual, but can reach as many as 500 individuals and spread over a 100 ha area. Isolated colonies form a metapopulation, with frequent local extinctions and colonizations of suitable habitat patches. Population density is 4-5 individuals/ha. Population size does not fluctuate between years of low and high rainfall. Predators include culpeo foxes (Pseudalopex culpaeus), which take both adults and juveniles, and Magellan-horned owls (Bubo magellanicus), which prey mainly on juveniles [3].
[edit] Pelt industry
See Fur industry
[edit] Conservation status
The Chilean chinchilla is endangered, with the 2nd highest conservation priority among Chilean mammals[6]. Wild populations are listed in CITES Appendix 1. As a result of overharvesting for its fur, the entire species was almost extirpated during early 1900s. Despite protection provided by an agreement signed between governments of Argentina, Bolivia, Chile, and Peru, and under Chilean law since 1929, poaching continued. By 1950s, the Chilean chinchilla was considered extinct. Wild populations were rediscovered in 1978, and in 1983 Reserva Nacional Las Chinchillas was created. This reserve comprises 4,227 ha, of which 556 ha had colonies before 1983, but only 264 ha had colonies in 1989. The former distribution has been reduced primarily to only 2 areas. Only 19 of 42 known colonies in Reserva Nacional Las Chinchillas currently are protected. The total wild population is estimated as 2,500–11,700 individuals and is declining, as indicated by reduction in area covered by present colonies and their fragmentation. Although protected inside the reserve from human activities since 1987, population size continues to decline. A conservation plan has been in place since 1990, but no particular conservation action is being taken for the small genetically rich northern population of La Higuera, in Chile [3].
[edit] References
- ^ Jiménez, J.E. (1996), “The extirpation and current status of wild chinchillas (Chinchilla lanigera and C. brevicaudata)”, Biological Conservation 77: 1-6, DOI 10.1016/0006-3207(95)00116-6
- ^ a b c Bennett, E.T. (1835). "On the Chinchillidae, a family of herbivorous Rodentia, and on a new genus referrible [sic] to it". Transactions of the Zoological Society of London 1: 35–64.
- ^ a b c d Spotorno, Angel E.; Zuleta, C.A., Valladares, J.P., Deane, A.L., and Jiménez, J.E. (15 December 2004). "Chinchilla laniger". Mammalian Species 758: 1–9. doi:. PDF
- ^ Wilcox, H. N. (1950). "Histology of the skin and hair of the adult chinchilla". Anatomical Record 108: 385–397. doi:. PMID 14799877.
- ^ Bickel, Edmund (1987), Chinchilla Handbook, Neptune City, NJ: T.F.H. Publications, Inc., ISBN 0-86622-494-7.
- ^ Cofré & Marquet, P.A. (1999), “Conservation status, rarity, and geographic priorities for conservation of Chilean mammals: an assessment.”, Biological Conservation 88: 53-68, DOI 10.1016/S0006-3207(98)00090-1
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