Pantholops hodgsonii (Abel, 1826)

Don E. Wilson & Russell A. Mittermeier, 2011, Bovidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 444-779 : 667-668

167.

Chiru

Pantholops hodgsonii

French: Chiru / German: Tschiru / Spanish: Antilope tibetano

Other common names: Tibetan Antelope

Taxonomy. Antilope hodgsonii Abel, 1826 ,

Tingri Maidan, Tibet.

Molecular and morphological studies align the Chiru most closely with Caprinae, but in the past, it has been classified alone in a tribe Pantholopini or with saigas (Saiga spp.) in a tribe Saigini because of unique behavioral and morphological characteristics. Monotypic.

Distribution. The Chiru is endemic to the Tibetan Plateau in the Chinese provinces of Xinjiang, Qinghai, and Xizang; it also occurs in very small numbers in the Ladakh district of NW India, mainly during summer.

Descriptive notes. Head-body 100-140 cm,tail 13-14 cm, shoulder height 79-94 cm; weight 24-42 kg. Sexes of the Chiru are distinguished by the larger mass of males and male-only, slender, long, lyre-shaped black horns with circular rings toward their base; the tips are rapier-like. The horns are remarkably uniform in length, usually measuring 54-60 cm; horns longer than 70 cm are extreme. The circumference at the base of the horn averages 12 cm. The greatest variation is in the tip-to-tip span, which ranges from 19 cm to 46 cm. Horns have no age rings, and there is no evidence that they continue to grow after males reach adulthood at about four years of age. In profile, the upright and often symmetrical horns on adult male Chirus led to early descriptions like “Unicorn of the ancient Persians.” The Chiru is somewhat chunky with slender legs. It lacks preorbital glands and pedal glands, but does have large inguinal glands, developed to fist size in males. The pelage is dense and woolly, and the undercoatis very fine. Color is pale fawn with pink to red to brown hints dorsally, fading to a whitish belly. As rut approaches, males older than 3-5 years attain a striking whitish nuptial pelage that contrasts with an almost black face. The muzzle of the Chiru is conspicuously swollen by walnut-sized lateral nasal chambers, more so in males. The coloration of muzzle swelling in males varies from grayish-brown in Xizang and Qinghai, to white in Xinjiang, providing a sharp contrast to the black face. Legs are grayish, and males have black stripes running down the front of all four legs that are particularly obvious during rut. Neither sex has a distinct rump patch. The ears are short, somewhat pointed, and white on the back. The tail is short and not tufted, and colored like the rump and back. Dental formula is 0/3, C 0/1, P 2/2, M 3/3 (x2) = 28, reduced because of the absence of an upper and lower premolar. The missing pair of premolars in the Chiru is similar to that in saigas, which lack the anterior lower premolars; loss of such dentition is probably related to diet. Canines are incisoriform, and the upper molars have pronounced external folds; the lobes are concave between and almost without medial ribs. The deciduous teeth are replaced first, with permanent incisors and third molars beginning to appear at about twelve months of age, and full permanent dentition at 28-30 months. After 2-5 years, the age of a Chiru can be determined only by general wear in the center of molar cusps, which begins on the first molar and progresses to the third molar as an individual ages. Aging by counts of cementum annuli has not been satisfactory.

Habitat. Chirus inhabit alpine and desert steppe with flat to rolling terrain in about 800,000 km? of the Tibetan Plateau at elevations of 3250-5500 m. Such habitats are typified by sparse vegetative cover (c.10-15%) and low primary productivity (80-160 kg/ ha dry matter). Chirus occur infrequently in mountainous terrain.

Food and Feeding. The Chiru is a mixed feeder, seasonally eating grasses, sedges, forbs, and select parts of dwarf woody plants, although dietary diversity is constrained substantially by limited forage availability and diversity on the Tibetan Plateau and by local variation. Overall, grasses and sedges represent 33-66% of the diet, being most abundant in winter diets when Chirus dig through snow to obtain forage. Seasonally, the grass Stipa is important in winter, the sedge Kobresia is eaten most often in alpine meadows and steppe habitats in summer, and the dwarf shrub Ceratoides compacta is eaten most often in desert steppe and less so in alpine steppe. In Chang Tang National Nature Reserve, Xizang, annual percent use of various plants is graminoids: Stipa, 3-7-47-3%; Kobresia, 1-1-33-1%; Carex mooreroftiz, 0-5—-22-8%; herbaceous plants: Potentilla bifurca, 0-3-31-1%, Leontopodium, 0-2—11-9%; and dwarf shrubs: Ceratoides compacta, 0-2—63-5%, Ajaniafruticulosa, 212%. Summerdiets of spatially segregated male and female Chirus in Yeniugou, Qinghai, are somewhat different. There, males select Kobresia and forbs, and females select forbs, notably Potentilla, and avoid grasses and sedges. On calving grounds in desert steppe in the western Kunlun Mountains of Xinjiang, ruminal contents of adult females had 57% C. compacta and 43% grasses and sedges.

Breeding. The breeding season of the Chiru occurs in November-December, and a single young is born in late June—early July after a gestation of about 6-6-5 months. Age at sexual maturity is not clearly understood but, as in other ungulates of comparable size, it probably occurs at 1-5-2-5 years of age. Male hierarchy is not based on age, because males attain maximum size and horn length at about four years of age. Mature males are not territorial, but they form harems of up to about twelve females. Observations of the number of females per harem in Chang Tang National Nature Reserve are 1-4 females in 70% of them, 5— 8 females in 25%, and more than nine females in 5%. Male Chirus tend to space themselves individually throughout rutting areas and avoid serious horn-to-horn combat with various displays and interactions: head-up (28% of 54 interactions), neck-low (28%), exaggerated head-down (18%), and chases (22%). Only 4% of male-male interactions during rut are sparring. Most aggressive interactions involve a male trotting or lunging with head down and horns aimed at a rival; such behavior often terminates the interaction, but as rut intensifies, chases of up to 1 km are not uncommon. Vocalizations of rutting males may involve the enlarged nasal sinuses that serve as resonators, and include growls, croaks, and rather deep-toned roars. Courtship and mating are abrupt and brief, with only cursory displays and contacts. Early in rut, a male spends considerable time chasing females to maintain his harem; the females act disinterested. As rut progresses, females tolerate closer proximity of males and may circle back toward them when chased. When a female is receptive, the male approaches her with his head up in a distinctive walking gait, with forelegs stiff and raised high. While in close proximity to females, males do not display many of the courting behaviors common among ungulates; front-leg kicks that skim a female’s thigh are common, but the crouching, low-stretch behavior upon approach and vulva sniffing, nuzzling, and licking have not been observed. Occasionally, males display a lip curl after inspecting an area where a female has urinated or defecated. A male copulates by rearing upright, balancing on his hindlegs, with minimal contact with his mate. Neonates are precocial; they can arise and nurse 12-15 minutes postpartum and follow their mother one hour postpartum. Mean body mass and mean shoulder heights of young Chirus are: four-month-olds, 15-5 kg and 63-4 cm; 16month-old females, 20-9 kg and 67 cm; and 16month-old males, 25-5 kg and 76-8 cm. Ratios of young Chirus to adult females suggest that typically up to twothirds of individuals die before two years of age. Years of near-complete reproductive failure occur from extreme weather before, during, and after parturition.

Activity patterns. There is little information available on specific daily activity patterns of Chirus, but they do forage while migrating. Oestrid flies directly affect their activities and behavior in summer. One fly species burrows under the skin and consumes flesh on the rump and lower back before emerging, and the other species infects the nasal sinuses and the throat. Harassment by these flies causes Chirus to stand in groups of 50 or more in knee-deep water or on mudflats, ice patches, or high ridges, and perhaps explains why they dig their characteristic summer bowl-shaped hollows in sand and silt for near total concealment, a behavior also thought to involve predator avoidance.

Movements, Home range and Social organization. Chirus are either migratory or sedentary (perhaps facultative), and both types generally display sexual segregation outside the breeding period, from January through October. Deep snows can cause Chirus to modify traditional migratory movements in search of forage and as a means of avoidance; they are not suited for efficient travel through snow. Oddly, migratory individuals of both sexes often leave winter ranges just when forage quality is beginning to increase in spring and move north into areas where vegetationis still dormant and apparently of lower quality. Satellite imagery between 2000 and 2004 in Xinjiang showed that primary production was more than twice as high on the winter range of the Chiru as it was on calving grounds when the females arrived to give birth. Such northward migration to calve seems ill timed relative to phenology, weather, stage of pregnancy, insect harassment, and ease of movement. It may be that Chirusstill follow migratory patterns that were established when glacial and vegetative conditions were different. Females also may be moving to calving grounds with low numbers of predators and other sympatric ungulates. Migratory females move greater distances than males, particularly in late spring—early summer when they can travel 300-400 km north to traditional calving grounds. Movement patterns of male Chirus are more diverse and leisurely, seemingly taking advantage of favorable forage availability, particularly in spring. Some males move to higher elevations in spring, apparently following new growth of vegetation. Some males move little between winter, summer, and rutting areas; others move short distances between winter and summer ranges; and still others move northward after winter and disperse widely, returning to rut in autumn. The Chiru is gregarious, and group sizes vary considerably depending on sex, time of year, migratory patterns, weather, and insect harassment; probably the only longlasting association is between a female and her young-of-the-year into its second year. No individuals have been maintained long enough in captivity to document longevity; as with other ungulates of comparable size, maximum life span in the wild is likely about ten years. Monthly adult sex ratios suggest differential mortality of males, not uncommon to ungulates. Winter sex ratios of migratory Chirus in Chang Tang Nature Reserve, where females and males occupy the same area, are 35-75 males: 100 females.

Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. From a high of perhaps a million or more, the extant population of Chirus was estimated at only 65,000 -72,500 in the mid-1990s and currently may be about 100,000, but no adequate range-wide census has been conducted. Some populations seem to have increased recently, but others have been extirpated. Many changes have occurred on the Tibetan Plateau in the past 30-50 years that have negatively affected the Chiru and other Tibetan mammals, including an expanding road network, increases in domestic livestock and resulting fencing and grassland degradation, often in the most productive habitats, changing land-use patterns by once exclusively nomadic pastoralists, and large-scale poaching. Notably, illegal trade in Chiru hides is an ongoing threat because of the black market for its wool, which is finer than cashmere and used to make expensive “shahtoosh” shawls and scarves ( US $ 1000-5000 each). It takes 3—4 hides to make a single shawl, and the wool cannot be sheared or combed because the fibers are very short and attached to the base of guard hairs. According to the Chinese government, about 20,000 Chirus were poached annually in the late 1990s, primarily to make shahtoosh shawls and scarves. Black-market bartering, with profit margins approaching 600%, often results in movement of bones and other parts of endangered Tigers (Panthera tigris ) to Asian markets in exchange for Chiru hides that move illegally into Nepal and India. Legal inroads have been made in thwarting traditional black market routes and worldwide demand for shahtoosh garments (Wildlife Trade Monitoring Network 1999), but continued vigilance and education are needed. To address the conservation of Tibetan ecosystems, the Chinese government has established an admirable network of reserves. The 300,000 km?* Chang Tang National Nature Reserve in north-central Tibetan Plateau is roughly the size of New Mexico ( USA) or Germany, making it the second largest reserve in the world. Important contiguous reserves to the north in Xinjiang include West Kunlun Reserve (30,000 km?), Mid-Kunlun Reserve (32,000 km?*), and Arjin Shan Reserve (45,000 km?*). Kekexili Reserve (45,000 km?) and Sanjiangyuan Reserve (150,000 km?) occur east of Chang Tang in Qinghai, but Chirus only occur in the western part of Sanjiangyuan. This impressive network of reserves is important to the Chiru because migratory populations move north and south between Xizang and Xinjiang and west and east between Xizang and Qinghai. The network currently encompasses about 75% of the known migratory routes of Chirus. Extant populations of Chirus, wild Yak ( Bos mutus ), and others are still threatened by human activities, including illegal harvest and competition with domestic livestock, and difficulties with enforcement of protective laws because of limited personnel and the expansive and very remote nature of the Tibetan Plateau.

Bibliography. Abel (1826), Blanford (1888), Cao Yifan et al. (2008), Fox & Bardsen (2005), Harris (2008), Harris & Loggers (2004), Harris & Miller (1995), Harris et al. (1999), Hodgson (1833, 1834), Leslie (2010), Leslie & Schaller (2008, 2009), Lian Ximing, Su Jianping et al. (2005), Lian Ximing, Zhang Tongzuo et al. (2007), Lydekker & Blaine (1914), Mallon (2008b), Pocock (1910), Prater (1980), Qiu Li & Feng Zuojian (2004), Rahmani (2001), Rawling (1905), Rockhill (1894), Roosevelt & Roosevelt (1926), Schaller (1998), Schaller & Ren (1988), Schaller, Kang Aili, Cai Xinbin & Liu Yanlin (2006), Schaller, Kang Aili, Hashi Tashi-Dorjie & Cai Ping (2007), Schaller, Lu Zhi et al. (2005), Schaller, Ren Jurang & Qiu Mingjiang (1991), Sclater & Thomas (1887), Shrestha (2001), Traffic Network (1999), Wright & Kumar (1997).

Figures

167. Chiru (Pantholops hodgsonii), 168. Rocky Mountain Goat (Oreamnos americanus), 169. Mishmi Takin (Budorcas taxicolor), 170. Bhutan Takin (Budorcas whitei), 171. Sichuan Takin (Budorcas tibetana), 172. Golden Takin (Budorcas bedfordi), 173. Aoudad (Ammotragus lervia), 174. Arabian Tahr (Avabitragus jayakari), 175. Himalayan Tahr (Hemutragus jemlahicus), 176. Greater Blue Sheep (Pseudois nayawr), 177. Dwarf Blue Sheep (Pseudois schaeferi)

Distribution. The Chiru is endemic to the Tibetan Plateau in the Chinese provinces of Xinjiang, Qinghai, and Xizang; it also occurs in very small numbers in the Ladakh district of NW India , mainly during summer.