Brief Introduction to Study on Ili Pika (Ochotona iliensis)

Li Weidong

(Xinjiang Institute of Environment Protection, Urumqi, China)

In 1983 and 1985 I collected a new species of Lagomorpha from the Tianshan Mountains, Nilka County, Xinjiang, China.Subsequently, the new species was named Ochotona iliensis Li et Ma, 1986.For more than ten years since the discovery of the Ili pika, we have studied its taxonomy, characteristics, habitat, distribution, population ecology, daily activity rhythm, reproductive biology and feeding habits.The results show that this is a special species of pika, and that it is also a species threatened with extinction.

TAXONOMY

Three type-specimens were identified during the initial phase of study and classification of the Ili pika:1)the holotype #83001, adult, collected from 3,200m altitude on 5 August 1983; and the paratypes, #85003, adult, and #85004, subadult, collected from 3,300m altitude on 13 and 14 August 1985, respectively. The holotype and paratype #85004 are preserved at the Xinjiang Institute of Environment Protection, Urumqi, whereas the paratype #85003 is preserved at the Institute of Zoology, Academia Sinica, Beijing.

The Ili pika is a very beautiful animal with generally bright coloration.There are big rusty-red spots on the forehead and the crown, as well as on the sides of the neck. The neck spots are connected under the throat.Hair color behind the ears and on the nape is pale. The Ili pika is rather large in size; the adult total length is more than 200mm, and the greatest length of skull is more than 45mm.In addition, the Ili pika is markedly distinguished from all other named forms of Ochotona by its ear and hind foot being the largest in length.

The incisive and palatal foramina are widely confluent, forming a single pear-shaped opening, and the vomer is completely discovered.There is not a small oval foramen in the anterior end of each frontal.The interorbital breadth amounts to 5.3mm, which is longer than 11% of the condylobasal length of the skull.

HABITAT AND DISTRIBUTION

Habitat:The Ili pika is a talus-dwelling animal.Talus districts with altitudes of 2,800 – 4,100m provide their primary habitat.They live mostly in slightly sloping large rock walls with a great number of gaps or holes. Usually, gaps or holes in the rock walls serve as their dens (fixed or temporary).The slight slope areas provide places for foraging and other activities.

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Distribution area:So far the known distribution area of the Ili pika includes only the Tianshan Mountains in China.The region of the type locality (Jilimalale Mountain) occurs in the eastern part of the range, where it winds along the north slope of Borohoro Mountain and Ilianhapilga Mountain, forming a belt-like zone which lies between 82o 21‘ and 87o 35‘ E.It also occurs in the north branch of Tianshan Mountains in Nilka, Jinhe, Usu, Shawan, Manas, Hutubi, Changji, Urumqi, and Toksun Counties. Subsequently, we have found the Ili pika in the south branch of Tianshan Mountain between 80o 55‘ and 84o 50‘ E, where it is distributed in Luntai, Kuqa, Baicheng, and Hejing counties. The south Muzate river valley in the southern Tianshan Mountains forms the boundary between the Ili pika and Large-eared pika (O. macrotis). According to our study, the area occupied by the Ili pika measures 13,500 km2 (450 ×20 - 40 km) and 5,800 km2 (230 × 20 - 30 km) in the southern and northern areas in the Tianshan mountains, respectively.Thus, the total area occupied is less than 20,000 km2, but only 17.05% of this area is suitable habitat (slightly sloping large rock walls) and/or is inhabited by the Ili pika, so that its area of distribution is very limited.

ECOLOGICAL CHARACTERISTICS

As shown by Smith et al. (1990), there are significant differences in biology and ecology between species of talus-dwelling and burrowing Ochotona. The Ili pika is a characteristic non-burrowing talus-dwelling species.As with most pika species, the Ili pika has the habit of storing vegetation in caches.Like most talus-dwelling forms, it lives at relatively low population density and its densities do not vary greatly with time, and individuals may live to relatively old age compared with burrowing species. It generally lives alone and at very low population density.The species is notably lacking in conspecific social relationships.Perhaps as a result, Ili pika does not liaison by voice.An important distinction with other pikas is that the Ili pika exhibits nocturnal activity, in addition to its diurnal activity.

POPULATION CHARACTERISTICS

In our investigations only 27 Ili pikas have been found.Taking into consideration the relative density of the species (0.87%) and the ratio of suitable habitat it occupies throughout its range (17.05%), we conclude that the total population number is approximately 2,900 – with only about 2,000 mature individuals.In addition to its low population size, the habitat it occupies is severely fragmented.According to the IUCN Red List Categories (1994), the Ili pika is an Endangered species of Lagomorpha.In fact, the situation faced by the Ili pika may make its existence even more threatened with extinction than Kozlov’s pika (O. koslovi), of central China, which has been considered one of the most threatened lagomorphs on earth.

REPRODUCTION

As the pika has a limited area of distribution andlow numbers, our data were obtained only by field observations, feeding trials in artificial conditions, and dissections and microscopic examination of hunted or captured animals.

During our extensive period of study, only one juvenile pika(in September) and three subadult pikas (in July) were found.Frequency of estrus is most common in early May, and at that time microscopic examinations of ovarian follicles showed a considerable number to be mature.It is possible that the pikas breed in early spring and produce first litter born in early June, with a second litter appearing in late July or early August.As the pika’s population density is very low and habitat conditions are very rigorous, perhaps some female pikas may not breed in any given year, and perhaps some females produce only one litter in a year.The sex ratio (males/females) is 1:0.8, and the population is comprised of 28.57% young and subadults – based on captured and observed pikas.

ARTIFICIAL FEEDING TRIALS

We raised Ili pikas in an artificial field habitat in Yining City (at an altitude of 660m), Xinjiang.For ten months observations were conducted under the condition of artificial feeding -- including capacity for eating, change of feeding habits, adaptability to low altitude circumstances, responses to infectious diseases, and so on.The results show that this alpine animal can adapt to a new artificial environment at low altitude, and can change its feeding habits from field plants to vegetables (celery and others).The species is gentle and docile, and it can thrive on a wide selection of plant material.In addition, the Ili pika was easier to raise and train than other animals.It seems that the Ili pika could become a new kind laboratory animal.

DAILY ACTIVITY RHYTHM

Under normal conditions, most pika species are considered to be diurnally active, and to be only occasionally active at night.However, we found that the timing of Ili pika activity was different from other known species (except the little pika, O. pusilla), based on our field observations.In addition, the daily activity rhythm of the Ili pika was studied with an automatic activity recorder refitted by us in a man-made outdoor environment.The main results were the following:1) the Ili pika has a characteristic of nocturnal activity; 2) for several seasons of observation, the mean rate of diurnal activity was 34.22%, and that of nocturnal activity was 47.42%; the static periods of activity are repeatedly alternative in a day; 3) seasonal changes of the active rhythm revealed that the main winter peak in activity was in the morning (9:00), and at other seasons the peaks were near midnight (Autumn 22:00 -- 2:00; Spring 23:00 -- 3:00). Generally, intermittent activity occurs after the main activity peaks; 4) the activity rhythm in May and that of other periods are significantly different; the reason for high activity rates in May could be because of breeding during that period; and 5) correlation analysis activity patterns with six independent variables showed that temperature was main correlative factor.

REFERENCES

Li Weidong and Ma Yong. 1986.A new species of Ochotonidae, Lagomorpha, Acta Zool. Sinica 32(4): 375-379.

Li Weidong, Li Hounchun, Xamaridan Hamit and Ma Junjie.1988.First report on ecological study of the Ili pika (Ochotona iliensis) Abstract Symposium of Asian-Mammalogy, Beijing.

Li Weidong, Ma Junjie and Xamaridan Hamit.1994.A Preliminary Research on the Artificial Feeding of Ili Pika, Chinese Journal of Vector Biology and Control 5(2): 130—133.

Li Weidong, Zhao Wei, Xamaridan Hamit, and Ma Junjie.1991.A Preliminary Study on Ecology of the Ili Pika and Its Relationship with the Plague Natural Foci, Chinese Journal of Vector Biology and Control 2(3): 202—205.

Li Weidong.1997.An Endangered Species of Lagomorpha ----Ili Pika (Ochotona iliensis), Chinese Biodiversity 5: (supplement) 23—28.

Li Weidong, Xamaridan Hamit, and Ma Junjie.1995.A Preliminary Observation on the Pelage and Seasonal Moult Order of Ili Pika (Ochotona iliensis), Chinese Journal of Zoology 29(2): 37—38.

Li Weidong and Zhao Wei.1991.The Component Species of Genus Ochotona and Its Distribution Areas in Xinjiang, Chinese Journal of Vector Biology and Control 2(5): 305—308.

Li Weidong, Li Hounchun, Xamaridan Hamit and Ma Junjie.1991.A Preliminary Study on the Distribution and Habitat of Ochotona iliensis, Chinese Journal of Zoology 26(3): 28--30.

Li Weidong, Li Hounchun, Xamaridan Hamit, Ma Junjie and Zhao Wei.1993.A Preliminary Research on Daily Activity Rhythm of Ili Pika, Acta Zoologica Arid Inland 1:54—57.

Smith A. T., Smith H. J., Wang Xuegao, Yin Xiangchu and Liang Junsium.1998.Social Behavior of the Steppe Dwelling Black-lipped (Ochotona curzoniae), Acta Theriologica Sinica 6(1): 13—14.

Smith A. T., Nikolai A. F., Robert S. Hoffmann., Zheng Changlin, Margarita A. Erbajeva. 1989.Life History, Status and Distribution of the Pika, Abstract of Papers and Posters, Fifth International Therological Congress: 199-200.

Smith A. T., Nikolai A. F., Robert S. Hoffmann., Zheng Changlin and Margarita A. Erbajeva.1990.The Pika. In Rabbits, Hares and Pikas: Status survey and conservation action plan: 14—60. Chapman. J. A. and Flux J. A. C. (Eds). Gland. Switzerland: IUCN.

Photographs by Li Weidong