The first direct observation of Crocodylus siamensis in Lao PDR in the last thirty years

Mateus, O. (2001).  The first direct observation of Crocodylus siamensis in Lao PDR in the last thirty years. Amphibia-Reptilia. 22, 253-256.



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The Siamese crocodile (Crocodylus siamensis) is one of the less known species of extant crocodiles. The ecology and status of C. siamensis is substantially unknown. The range of this species includes Lao, Cambodia, Thailand, Vietnam, Indonesia, and Malaysia, and it is quite rare in these countries. It is cited in CITES Appendix I, and recently classified as Critical Threatened by IUCN (1996). The existence of wild populations in Malaysia and Indonesia cannot be con rmed presently. Thai and Vietnamese stocks were almost completely extirpated, and only Lao and Cambodia have populations that might be viable (Sebastian, 1993; Cox et al., 1998; MRCS/UNDP, 1998; Ross, 1998). The 1992 Action Plan of the Crocodile Specialist Group for this species considered the availability of survey data extremely poor, with a highest need for information on wild population recovery. Moreover, the CSG ranked this species as one of the world’s most endangered among crocodilians. The highest priority for this species is that status surveys be conducted in Southeast Asia (Thorbjarnarson et al., 1992). Thorbjarnarson et al. (1992) wrote “The only known wild population was located in the Bung Boraphet Reservoir in Thailand; however no recent sighting of crocodiles have been made at this site (: : :). No adequate survey data are available from any part of the Siamese crocodile’s range”. General population levels are low and have been extirpated from several areas. They nevertheless still occur in some places along the Mekong (Sawathvong, 1994). Recent data and new places, in Thailand, Lao and Cambodia, were reported by Salter (1993), Kreetiyuntanont (1993), Ratanakorn et al. (1994), Thuok and Tang (1994), Davenport et al. (1997), Doroshenko (1998) and Stuart (1999) but all were based on local interviews, vocalisations or presence of faeces or tracks, with no direct observation whatsoever. In Lao PDR Stuart (1999) considers the species At Risk. Salter (1993) and Stuart (1999) deduct from interviews with local people that crocodiles may still be present, in the southern and western parts of Lao ( g. 1). Apparently, crocodiles were abundant and usually shot during the rst half of the 20th century according to Bassenne (1912). Apart local people, the last direct observation of Crocodylus siamensis until now was reported by Wharton (1966) in the 1950s and 1960s along Lao-Cambodia border where crocodiles were regularly hunted. The observation here reported represents the rst direct observation of C. siamensis made in the wild by a non-local person since Wharton (1966), more than thirty years ago. Direct observation of a juvenile crocodile was made on 30 November 1998 (around 10.00 hrs) by the author and Prof. Philippe Taquet (MNHN Paris). The specimen was seen in a small pond with stagnant water and a large abundance of shes, near the village of Ban Nathom in Atsaphone district, Savannakhet province. The pond and the surrounding tropical forest (Nathomdong) are considered sacred by the villagers (of Phuthai ethnic minority) and, therefore, preserved. The specimen was identi ed as Crocodylus siamensis. No erroneous identication is possible since this it is the only species known to occur in Lao (Stuart, 1999), C. porosus being absent from inner continental waters. The juvenile, with about 60 centimetres of total length, was just seen two meters far from the author. Since the observation is from a juvenile specimen, this means that the area is still a reproductive site for the population. Excrement 21 cm long and tracks on the sand also suggest the existence of individuals, two meters long, at least. Therefore, this area deserves a careful investigation due to its potentiality in a new stable population. Lao population of Siamese Crocodiles are of extreme global importance, as the last viable speci c populations are thought to exist here and in Cambodia (MRCS/UNDP 1998; Ross, 1998). Therefore, the importance of this new site for the conservation of Siamese Crocodile might be very high if a viable population is present in the area.

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