NAT. HIST. BUL L. SIAM So c. 41: 135-137 ，1993

NOTES

Siamese Siamese Crocodile (Croco のlus siamensis Schneider ， 1801) in in Khao Ang Ru Nai Wildlife Sanctuary ， ， Thailand

The Siamese Crocodile (Crocodylus siamensis Schneider 1801) ， which occurs in Th ailand ，Cambodia ，Laos ，Vietnam ，Java ，Bomeo and Burma ，is one of rarest wild animals in in the world (BA 町&HUMPHREY ， 1980; TISTR ， 1991). This is a result of over-hunting for for crocodile skins and because of humans encroaching on its habita t. There are approximately approximately 300 of these crocodiles remaining in the wild in the world. The number of crocodiles crocodiles has decreased rapidly in Th ailand to a critical leve l. The 1986 IUCN Red List of of Threatened Animals has classified the Siamese Crocodile as "Endangered" ，meaning that that the species will become extinct soon if protective measures are not taken. Even though though crocodile farms are breeding many crocodiles in captivity ， the captive Siamese Crocodile Crocodile is losing its genetic characteristics ， because of crossbreeding with the Estuarine Crocodile Crocodile (C. porosus) and through inbreeding. Two other species of crocodiles also occur in Thailand: the Estuarine Crocodile (C. porosus porosus Schneider ， 1801) and the False Gharial (Tomistoma schlegelii S. Muller ， 1838). These These two species are also considered to be endangered by IUCN. The population sizes of of all three species in Th ailand were estimated at around 100 animals many years ago (YANGPRAPAKORN ET AL.， 1971b). This This progress report covers the results of a survey of crocodiles in the following conservation conservation areas: Phu Khieo Wildlife Sanctuary ，; Yot Dom Wild- life life Sanctuary ，Ubon Ratchathani Province ，Khao Ang Ru Nai Wildlife Sanctuary ， Chachoengsao Chachoengsao Province ，Pang Sida National Park ， Province and Kaeng Krachan National National Park ，Petchaburi Province. We have little information on Siamese Crocodiles in nature nature because no one has ever researched and studied the species in the wild. In In February ，1993 ， as Chachoengsao Wildlife Research Officer ，1 began to survey the crocodile crocodile population in Khao Ang Ru Nai Wildlife Sanctuary. The first tracks of Siamese Crocodile Crocodile were found on February 14 ， in the region of the creek Khlong Takrao. Th e tracks tracks were followed until a Siamese Crocodile was encountered and photographed on February February 20 (Fig. 1). The body length was 30 0- 350 cm. It was the first time that Siamese Crocodile Crocodile had been observed in the wild in Khao Ang Ru Nai Wildlife Sanctuary. Additional Additional surveys in Khao Ang Ru Nai Wildlife Sanctuary revealed a second set of footprints footprints in a tributary of Khlong Si Yud about 35 km from the first se t. The Khlong Si Yud and Khlong Takrao are tributaries of the . The Siamese Crocodile population population in Khao Ang Ru Nai Wildlife Sanctuary is probably very smal l.

Khao Ang Ru Nai Wildlife Sanctuary area is 1030 km 2 and includes 紅 eas in five provinces: provinces: Chachoengsao ，Rayong ，Chantaburi ，Prachinburi and Chonburi. This area is the largest largest lowland forest in Thailand. This This is the most definite evidence for the existence of the Siamese Crocodile in the wild wild in Thailand. There are reasonably reliable reports of the species surviving in four

135 135 136 136 KI 1T 1 KREETIYUTANONT

other other protected areas. Most recently in July 1993 ，1 found the tracks and basking 釘 'ea of crocodile a crocodile in Phu Khieo Wildlife Sanctuary ，Chaiyaphum Pr ovince. In April of 1993 a crocodile crocodile w 出 spotted in a stream from a plane in Pang Sida National Park ，Prachinburi Province. Province. A c 釘 C邸 s of a crocodile was found by Dr. Panthep Ratanakorn (pers. comm.) recently recently in Yot Dom Wildlife Sanctuary ，Ub on Ratchathani Provinc 泡. Finally ，1 have seen one one in the Petchaburi Ri ver in Kaeng Kra chan National Park ，Petchaburi Pr ovince ， where Mr. Mr. Jarujin Nabhitabhata (pers. comm.) also attests 白創出e species still occurs.

RE 回 RENCES

BAIN BAIN J.R. AND S.R. HUMPHREY. 1980. A Pro file of the Endangered Species of Th ailand. Report No. 4，Office of of Ec ological Service ， F1 0rida State Museum ，University of F1 orida ，Gainesv i1l e ，F1 orida.

IUCN. IUCN. 197 1. Status Report on the Crocodile of Th ailand. In Crocodiles. IUCN ，Morges ，Switzerland. IUCN. IUCN. 1975. Red Data Book. IUCN ，Morges ，Switzerland. IUCN. IUCN. 1986. Red List ofThreatened Animals. IUCN ，Morges ，Switzerland.

THAILAND THAILAND INSτITUTE OF SCIE NTl AC AND TEc HNOLOGICAL R邸臥RCHσISTR) ，Ec ological Research Division. 1991. Endangered Endangered Species and Habitats of Thailand. TISTR ，

Kitti Kitti Kree 均， lutanont Chief Chief Assistant of Chachoengsao Wildlife Wildlife Research Station Royal Royal Forest Department Pr esent address: Phu Kh ieo Wildlife Sanctuary P.O. P.O. Box 3 Am phur Chumpae Khon Kaen 40130 ，百 lailand 5 1八MESE C ROCOD IL E IN K Il i¥ O i¥ NG RU N 八l 、V ILD Llf- E Si¥ NC T UflRY 137

F igur e 1. Crocody l川川l1I ell sis (3 .0 - 3.5 111 ) in Khao A ng Ru Na i Wi ld lir e SanClll 山 y，K hl ong Tak rao ，in F e b. 1993