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Abstract. The progesterone (P4) profiles and macroscopic vulvar changes of female Malayan tapirs were investigated in order to understand their fundamental reproductive physiology and to search for visual indicators of estrus. Blood was collected once or twice a week from seven female Malayan tapirs kept at four zoos. Serum or plasma P4 concentrations were determined by radioimmunoassay. The P4 concentrations changed cyclically throughout the years, and a total of 56 cycles was confirmed in the seven females. The length of the estrous cycle based on the P4 profiles was 43.6 ± 2.0 days; however, this mean includes great variation in length, from 21 to 84 days. Mucous discharge from the vulva and vulvar swelling were seen when the P4 concentrations were low before the beginning of a rise in most cases. In conclusion, captive female Malayan tapirs have variations of approximately 1 to 3 months in estrous cycle length, and visual changes in the vulva are helpful in estimating estrus in female Malayan tapirs.

ABSTRA⊂T． The aims of the present study were to chara ⊂terize differences ln behavior between copulatory and non − copulatory periods in male and female Malayan tapirs ( Tapirus indicus )and to illustrate the characteristics of estrus − related behaviors in female tapirs． Megascopic observations were performed using two procedures f(〕r two pairs of male and female Malayan tapirs in captivity， In observation 1， five behavioral categories ， Attract (♀ → ♂ ) ， Chasing( ♂ → ♀ ) ， Mounting( ♂ → ！ ) ， Copulation( ♂ )and Vocalization ( 9 ) ， were recorded as present or absent within a day fbr over lyear， In observatlon II ， eighteen behavioral categories of maintenance and reproductive behaviQrs were recDrded by Vocalization stgnificantly increased arld Spray urination had a tendency to increase in the copulatory period than non − copu ］ a 亡 ory period ． In contrast ， Res亡 ing significantly increased in the non − copulatory period ・ The es 亡 rous cycle based on the serum progesterone prD 且les of a female was 46 、 3 ± 4． 9 days and thus well corresponded to the copulatory cycle leng 〔 h；therefbre ， it seerns that increased vocalization and possibly spray urination are estrous signs in female Malayan tapirs． Key word l estrus ， Malayan tapir ， progesterone ， reproductive behavior Jpn． ∫ Zoo ． Wildt ． Med ． 13 ( 2)． 45 − 50， 2008 INTRODU⊂TlON The Malayan tapir ( Tapirus indicus )belongs to the fami ｝ y Tapiridae ， including the order Perissodactyla， and lives alone 互 n the tropical rnoist forests of central and southern Sumatra 、 Thailand ， Malaysia and Myanmar 、 This speeies faces a high risk of extinction in the wild because of habitat loss and degradation ， harvesting， hurnan disturbance and others ． According to the IUCN Red List of Threatened Species， Malayan tapirs are classified as Vulnerable ［ 1ユand especially the Sumatran popula し ion of this species is listed in Endangered ［ 2ユ ． According to the Japanese Studbook of Tapirs 、 34 Malayan tapirs are kept at lOzoological facilities in Japan( December， 2006data ) ［ 3］ ． Afew offspring are born every year in Japan； however， only Iimited pajrs breed successfu 】 ly ． Currently ， establishing new breeding pairs is actively promoted as part of the captive propagation program for tapirs・ It has been reported that the estrous cycle length in Malayan tapir is approximately l month based on the interval between the days when courtship and copulation were obserVed

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