The pika inhabiting in cold zone or in high mountains is thought to be adapted to cold as well as high-altitude environment. We have reported pika\u27s high body temperature (39.6℃), high metabolism and poor heat loss ability such as poor panting, small ear pinnae and lack of thermal salivation. In this study, we measured the body temperature of wild pikas (Ochotona daurica) with a telemetry device in their natural burrows in Mongolia. Two pikas captured at Undur Dov were implanted with transmitters in the abdominal cavity under anesthesia, and were returned to the own habitat. The mean body temperatures of the pikas were 39.65℃ and 39.96℃ though the data were limited to a short period of less than one day. The present results in wild pikas support pika\u27s high body temperature in our previous studies

Ganzorig Sumiya

Kosaka Mitsuo

Matsumoto Takaaki

Matsuzaki Tetsuya

Nomura Tatsuji

Ohwatari Nobu

Saito Muneo

Sakai Akio

Shimazu Munenori

Nagasaki University's Academic Output SITE: NAOSITE

Trop. Med., 37 (3), 93-98, September, 1995 93A Field Study of Telemetry-Recording ofThe Body Temperature in Wild Mongolian PikasTakaaki MATSUMOTO1, Mitsuo KOSAKA1, Muneo SAITO2,Akio SAKAI3, Tetsuya MATSUZAKI4, Sumiya GANZORIG5* ,Nobu OHWATARI1, Munenori SHIMAZU1, and Tatsuji NOMURA2Department of Environmental Physiology, Institute of Tropical Medicine, NagasakiUniversity, Nagasaki 852, Japan2Central Institute for Experimental Animals, Kawasaki 21 6, Japan^Research Center for Aging and Adaptation, Shinshu University School of Medicine,Matsumoto 390, Japan4National Institute of Neuroscience, National Center of Neurology一i and Psychiatry,Tokyo 187, Japan5Department of Zoology, National University of Mongolia, Ulaanbaatar, MongoliaAbstract: The pika inhabiting in cold zone or in high mountains is thought to be adapted to coldas well as high-altitude environment. We have reported pika's high body temperature (39.6℃),high metabolism and poor heat loss ability such as poor panting, small ear pinnae and lack ofthermal salivation. In this study, we measured the body temperature of wild pikas (Ochotonadaurica) with a telemetry device in their natural burrows in Mongolia. Two pikas captured atUndur Dov were implanted with transmitters in the abdominal cavity under anesthesia, andwere returned to the own habitat. The mean body temperatures of the pikas were 39.65℃ and39.96℃ though the data were limited to a short period of less than one day. The present resultsin wild pikas support pika's high body temperature in our previous studies.Key words: Pika, Telemetry, Body temperature, MongoliaINTRODUCTIONThe pika lives in cold zone or in high mountains and attracts the attentions as an animalmodel of cold adaptation (Kawamichi, 1985; Yang et al, 1988; Yang, 1990) as well as high-altitudeadaptation (Sakai, 1988; Sakai et al, 1994). Previously, we have reported pika's high metabolicrate, high body temperature (39.6℃), heat intolerance and poor heat loss ability such as poorthermal panting, small ear pinnae and lack of thermal salivation (Kosaka et al, 1985; Yang et al,1988; Yang, 1990; Matsumoto et al, 1992). In those studies, however, the body temperature hadbeen measured in the laboratory raised pikas held in the hands. In July 1994, we collected thepikas in Mongolia and brought them to Japan for the breeding of the pika as a new laboratnrvReceived for Publication, May 16, 1995Contribution No. 3167 from the Institute of Tropical Medicine, Nagasaki University^Present address: Department of Parasitology, Veterinary Faculty, Hokkaido University,Sapporo 060, Japan9-1animal. During this expedition to Mongolia, the present field study was performed. In order toconfirm our previous results of pika's high body temperature, the body temperature was meas-ured in wild pikas in their own burrows by using a telemetry device in Mongolia.MATERIALS AND METHODSThe radio transmitter (TM-disc with 850MAH lithium battery, Mini-Mitter Co., Inc., OR,USA) and a citizens band transceiver (TRC-244, Tandy Corporation, TX, USA) of which transmitfunction was disabled were used in this study. The transmitter (18mm in diameter, 34mm inlength and 13.5g in weight) sends the pulses corresponding with the temperature. We could heara periodic "cheep or "click" with each pulse of the transmitter by using a receiver. When the"transmitter was buried 50cm beneath the ground, the signal was received more than 50m in theopen field. As shown in Fig. 1, there was a linear correlation between the temperature and thepulse frequency in the range of temperature between 35℃ and 42℃ in each of the two trans-mitters. By measuring the pulse rate of the implanted transmitter and using the calibration curve,the deep body temperature of the subject animal is monitored.The two pikas (Ochotona daurica), weighing 150g and 183g respectively, captured at UndurDov (about 40km west of Ulaanbaatar, about 1350m above sea level), Mongolia, were used in thisstudy. In a tent just beside the habitat, a transmitter was implanted into the peritoneal cavity ofeach pika under ketamine hydrochloride (35mg/kg, i.p.) anesthesia. After the surgical procedure,the pikas were allowed to recover from the anesthesia in the cages, and they eventually escapedfrom the cages before being released.Ambient temperature and relative humidity were measured with digital humidity meter(HT-410, SOAR Corporation, NaganoのJapan) at Undur Dov for three consecutive days (July28-30, 1994).151414呈13>ご　13U孟12さ1ZLLJQi lliL91010505050505y-6.381 X-1 1 9.266, r2=o.999�"Y=5.339X-85.71 8, r双-o.996�"CH.B　27.795MHz°cH.C　27.835MHz34　35　36　37　38　39　40　41 42　43wATER TEMPERATURE. -CFig. 1. Calibration of the transmitters. There was a linear correlationbetween water temperature and pulse frequency in the rangebetween 35℃ and 42℃ in each transmitter.95RESULTSThe terrain around Undur Dov is a wide-opened steppe area with small elevations and theland is sparsely covered by the grass of less than 20cm in height. One of the steppe-dwelling pikas,Ochotona daurica, inhabits in this area. Their burrows are mainly found along a depression be-tween small ridges on the slide, where the plants are relatively dense and the wind is not strong.The burrow was composed of an under-ground network with several entrances.One pika was captured at 20.00 on July 26 (pika C) with a trap and the other at lO‥00 on July27 (pika B) around the same burrow. Both pikas recovered from anesthesia within a few hours andescaped from the cages before being released. The body temperature was monitored for 14 hoursin pika C and for 7 hours in pika B, respectively (Fig. 2). The mean body temperatures after therecovery from the anesthesia were 39.65℃ and 39.96℃ in pika C and pika B, respectively. In thepika C the body temperature just after the implantation was low, because the abdominal cavitywas washed with sterilized saline before closing with sutures. In the next afternoon on July 28, weunfortunately found that the pika C was dead (the pulse rate was very low comparable to theambient temperature). The strongest signal from the pika was recorded 70m distance from whereit was captured. Moreover, no signal was picked up from the pika B. Another two pikas were alsonoted on July 28 around the burrow where the first two pikas had been captured.The changes in ambient temperature and relative humidity at Undur Dov from July 28 toJuly 30 were shown in Fig. 3. It is the hottest month in July and mean ambient temperature is16.7℃ at Ulaanbaatar. During daytime, the ambient temperature varied from 13℃ to 22℃ andthe relative humidity was around 40% except rainy days. Even in July, the ambient temperaturedropped to 4.2 ℃ in the early morning (July 29) probably due to the massive radiant heat loss fromthe earth surface to the clear, dry sky at night.4140UOJU〔ヒ⊃ト<凸:LUQ_≡Ll｣ト>一�"°財3938373635.のJ一正d♂i＼＼ローーノ叫　　pIKA.C　(150g)PIKA.B　(183g)AT UNDUR DOV IN 1994Zl:00　0:00　3:00　6:00　9:00 12:00 15:0° 18:00　21:00July26 July27TIM E　　　　　　　　-CLOCKFig. 2. Body temperature in wild Mongolian pikas recorded with tele-metry devices in their natural burrows. Pika C escaped from thecage around 0:00 on July 27, and pika B around 13:00 on July 27.The mean body temperature of the two pikas after the recoveryfrom the anesthesia was 39.65℃ and 39･96℃ , respectively.96UOLU【亡=一ト<【ユ:山Q-2u｣ト｣の=〕ト育≡=一=≦E=5UJEZ:24ZZZO1816141210864290807060504030-R□Jul°y6o℃fiJuN,にyu落E9y28fio36一15182124July29l_l'¥July3｡/N/July2812　　15　　18　　21　　24T I M E O'CLOCKFig. 3. Ambient temperature and relative humidity at Undur Dov, Mongolia fromJuly 28 to July 30 in 1994. R indicates ram.DISCUSSIONwe have reported pika's high body temperature, 39.6 ±0･17°C (n- 15, Ochotona rufescens) at22-C of ambient temperature (Kosaka et al, 1985), 39.58ア0.38-c (n-9, 0. rufescens) at 26-C ofambient temperature (Matsumoto et al, 1992), 39.8±1･2℃ (n-17, 0. curzoniae), 39.6±0･3℃(n=6, 0. curzoniae), 39.6°C (n-2, 0. cawsws) in China (Kosaka efa/., unpublished), and 39.8±0.7 C;n=5, 0. curzoniae) in Tibet (Sakai, 1994). In the former two studies, the pikas raised in thelaboratory were used, and the wild pikas were studied in the field in the latter studies. The bodytemperature was measured in the pikas held in the hands, therefore, the influence of the restraintstress on the body temperature was not eliminated. It is well known that the stress induceshyperthermia in rats (Singer et al, 1986). By using a telemetry device, the body temperature canbe monitored in the animal without any influence of restraint stress under conscious condition.In this study, the body temperatures of the two wild pikas freely moving in their ownnatural burrow were recorded by using telemetry devices and were found to be as hi貞h as 39.65°Cand 39.96℃ , respectively. The present results, though the data were limited to a short period of97less than one day, provide the supportive evidence of pika's high body temperature reported inour previous studies.Another purpose of this study was to disclose circadian variation of the body temperaturein pikas. The pikas have been reported to be diurnal, most active at dawn and dusk (Kawamichi,1985), mainly diurnal (Broadbooks, 1965), active in day and night, especially in dawn and dusk(Haga, 1960) after the field observation, and nocturnal (Kosaka et al, 1988) after the recording oflocomotor activity in the laboratory. Telemetry recording of the body temperature is a good toolto investigate the circadian activity. Unfortunately, we failed in this purpose, because the trans-mitter was too large for the pikas used in this study. The transmitter is recommended to be lessthan 5% of the body weight, however, it happened to be 7.4% and 9.0% in this study. TheMongolian pikas (0. dauricd) were considerably smaller than our expectation based on the data ofAfghan pikas (0. rufescens rufescens} which weighed approximately 250g (Puget, 1973; Yang,1990). One pika was dead and the signal from another pika was lost after a few days. It wasspeculated that the pika's activity was diminished after the implantation of a heavy transmitterand that the pika might be captured by the predator and be taken out of the range where thetransmitter signal received. The smaller transmitter should be used for Mongolian pikas, ac-cording to our experience.One pika cruised 70m, which distance is in agreement with the previous observation thatthe pika's cruising radius is about 30 to 40m (Haga, 1960). As most steppe-dwelling pikas havebeen described as living together in a family, we encountered at least four pikas in a burrow.In winter it is about -20℃ to ｢30℃ at Ulaanbaatar･ Actually, it was recorded to be at4･2℃ even in July. Interestingly, we found in Mongolia that the pikas live next to the marmotswhich are the hibernators. The other hibernators such as chipmunks, golden-mantled squirrelsand ground squirrels are also the neighbors of the pikas in North America (Broadbooks, 1965).The pikas do not hibernate (Haga, 1960; Dawson, 1981), therefore, the pikas should developcharacteristic strategies to survive in the cold, other than hibernation. They live in the burrowsor in the shelter among rocks and boulders, and hoard grasses for winter food. Thus the pikas arethought to be ecologically adapted to the cold environments.It is considered that the pikas appeared in the cold area in the Pliocene and expandedsouthward during cold glacial periods, and retreated to the high mountains during warm inter-glacial periods in the Pleistocene. The current distribution of the pika ranges widely from low toextremely high altitude, about 10 to 6,100m above sea level (Sakai, et al, 1988), indicates that notthe altitude but the temperature is a limiting factor in the distribution of pikas. The pikas preferlow temperature and the temperature of their burrow is very low even in summer, about 12℃ to14℃ (Haga, 1960). The ratio of ear surface area to body surface area is very small (Yang, 1990)and thermal panting is poor (Yang etal, 1988) compared to rabbits, though heat radiation throughthe ear pinnae and thermal panting are major heat loss responses in rabbits. Furthermore, thepikas do not spread saliva on their body surface when exposed to heat (Matsumoto et al, 1992).Body temperature and metabolic rate in pikas are higher than rabbits (Kosaka et al, 1985). Thusdue to poor heat loss responses and high metabolism the pika is heat intolerant and adaptive to thecold. The pika is considered to be adapted to the cold not only ecologically but also through au-tonomic thermo-regulatory mechanisms.98AcKNOWLEDGEMENTThe authors thank Dr. R. Samiya and his co-workers (Institute of Bi♂logy, Nationaluniversity, Mongolia) for their help to capture pikas and useful information about the pikashabitats. This work was supported by a Grant-in-Aid for International Research (No. 06041131)and Grants-in-Aid for Scientific Research (No. 04304029, 06271253, 06557007) from the Ministryof Education, Science and Culture oりapan.REFERENCES1) Broadbooks, H.E. (1965): Ecology and distribution of the pikas of Washington and Alaska. Amer. Midi.Nat., 73, 299-335.2) Dawson, M.R. (1981): Lagomorpha. pp. 588-591. In The New Encyclopedia Britannica, vol. 10. Ency-clopedia Britannica, Inc., Chicago.3) Haga, R. (1960): Observations on the ecology of the Japanese pika. J. Mamm., 41 (2), 200-212.4) Kosaka, M., Ohwatari, N., Iwamoto, J., Tsuchiya, K., Fujiwara, M., Fan, Y-J., Matsuo, S., Moriuchi, T.& Matsuzaki, T. (1985): Studies of temperature regulation on pika (Ochotona rufescens rufescens); Anold-fashioned rabbit. Trop. Med., 27 (4), 289-294.5) Kosaka, M., Yang, G-J., Matsumoto, T., Ohwatari, N., Tsuchiya, K., Chen, C-M., Nakamura, K., Matsuo,s. & Moriuchi, T. (1988): Analysis of locomotor activity on pika (whistle rabbit). Trop. Med., 30 (3),213-218.6) Matsumoto, T., Yang, G-J., Kosaka, M., Yamauchi, M., Lee, J-M. & Tsuchiya, K. (1992): Weak heat to-lerance of pika (Ochotona rufescens rufescens)- Study of thermal salivation-. Jpn. J. Trop. Med. Hyg., 20(1),105-106.7) Puget, A. (1973): The Afghan pika (Ochotona rufescens rufescens): A new laboratory animal. Lab. Amm.Sci., 23 (2), 248-251.8) Sakai, A. (1994): Characteristics of high-altitude adaptation in Ochotona cu陀oniae captured at Tibetanhighland, pp. 37-43. In T. Nomura (ed.). Study on Pika (Ochotona) as Animal Models for High AltitudeAdaptation, (in Japanese)9) Sakai, A., Ueda, G., Yanagidaira, Y., Takeoka, M., Tang, G. & Zhang, Y. (1988): Physiological charac-teristics of pika, Ochotona, as high-altitude adapted animals, pp. 99- 107. In G. Ueda et al- (ed.). High-Altitude Medical Science. Shinshu University, Matsumoto, Japan.10) Singer, R., Barker, C.T., Vander, AJ･ & Kluger, MJ. (1986): Hyperthermia induced by open-field stressis blocked by salicylate. Physiol. Behav., 36, 1179- 1182.ll) Yang, G-J. (1990): Physiological Characteristics of pika (Ochotona rufescens rufescens) as a weak heattolerant animal. Trop. Med., 32 (4), 129-140.12) Yang, G-J., Matsumoto, T., Kosaka, M., Yamauchi, M. & Ohwatari, N. (1988): Poor heat loss ability ofpika (whistle rabbit). Trop. Med., 30 (1), 45-48.

A Field Study of Telemetry-Recording of The Body Temperature in Wild Mongolian Pikas

https://nagasaki-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=25335&item_no=1&attribute_id=18&file_no=1

A Field Study of Telemetry-Recording of The Body Temperature in Wild Mongolian Pikas

Abstract

Similar works

Full text

Available Versions

Nagasaki University's Academic Output SITE: NAOSITE