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