Tomistoma (Tomistoma schlegelii)


Photo Source: Mark Bezuijen

The Tomistoma Crocodile (Tomistoma schlegelii) is a unique crocodilian species, restricted to Sumatra, Borneo (Kalimantan and Sarawak), and Peninsular Malaysia.  It is ranked by the IUCN Crocodile Specialist Group (CSG) as one of the top five crocodile species (of 22 species globally) for highest-priority conservation and research action.

Prior to 1996, the global IUCN status of Tomistoma was listed as “Data Deficient”: very little was known of its ecology, distribution, abundance, or conservation status. In 1995-96, the first major field assessment of the species’ biology and status was carried out by Wildlife Management International Pty Limited (WMI), the CSG, and the Indonesian Ministry of Forestry, in Sumatra. This led to the species being listed as “Endangered” by the IUCN in 1998. In 2001 and 2002, 5-6 years after the original surveys, international funding enabled the researchers to return to original survey sites to quantify trends in status and conservation threats.

These surveys (Bezuijen et al. 1995, 1997, 2001, 2002), followed by dedicated Tomistoma surveys undertaken in West Kalimantan, from August to September 2004 suggest a continuous decline of Tomistoma throughout its global range. Of particular concern is the severe depletion of critical nesting habitat (swamp forest) throughout the species’ range.

Kalimantan is thought to possibly hold the largest global Tomistoma populations. A 2004 PRCF crocodile survey1 in West Kalimantan involved quantitative methods (spotlight counts), and identified some sites of global importance for the species. Survey objectives were to document Tomistoma status and distribution in selected sites, current threats, and potential follow-up management actions.  The 2004 surveys were conducted in the Tapah and Kepulu Rivers and Gunung Palung National Park–in the south of the province, the Sibau River located partlywithin Betung Kerihun National Park, and Danau Sentarum National Park (DSNP)–in the northeast of the province. The DSNP was first surveyed for crocodiles 8-10 years previously; other sites were previously unsurveyed for crocodiles.  The 2004 survey sites encompassed a range of habitats and protection status (protected/ unprotected).