Tomistoma schlegelii is a threatened crocodilian whose current range is restricted to Sumatra, Borneo (Kalimantan and Sarawak) and Peninsular Malaysia. During surveys undertaken in eastern Sumatra in 1995–1996, 15 T. schlegelii nests were located in peat swamp forest along a single tributary, the Merang River. No other areas with equivalent nest densities have yet been described. Although much peat swamp forest has been lost to logging and fire, it remains the dominant habitat in most of the current range of T. schlegelii. In the Merang River the peat swamp and T. schlegelii are threatened by a series of ongoing activities and both may be lost unless some form of innovative management programme is introduced. Peat swamp forest supports a range of other rare and threatened species, and would appear to have high conservation value. This paper reviews current information on the role of peat swamp forest in the ecology of T. schlegelii and describes the conservation threats to T. schlegelii in the Merang River.

Recent theoretical papers on temperature-dependent sex determination in reptiles are based on the assumption that crocodilian populations, particularly adults, are markedly female biased. While there is evidence that some crocodile populations may conform to this expectation, there is no compelling evidence that American alligator populations are female biased anywhere in the species' range. Previous data had indicated that some populations of juvenile and/or adult alligators were significantly male biased. However, these studies were criticized for sampling errors. Adult males typically occupy a different habitat from that of females, and males frequent areas where they are more likely to be caught. In contrast, in juveniles, both sexes occupy the same habitat. We determined the sex ratios of c. 3000 juvenile alligators collected from 11 sites over 6 years in south Louisiana. Our results indicate a significant sex bias (58% male), but variation was evident among samples. Sex ratios varied by year and site, and the interaction of these factors was significant. At one site in one year, there was a female bias (71%), but in no year was there an overall female bias across sites. From this study and earlier reports, we conclude that there is no evidence at present of female-biased sex ratios in the juvenile and/or adult alligator populations, and consequently, that certain models of temperature-dependent sex determination in reptiles require re-evaluation. Furthermore, our data suggest a pattern of differential mortality of females vs males during the first years of life, a pattern consistent with a key prediction of several differential fitness models for the adaptive significance of temperature-dependent sex determination in reptiles.