Biology and commercial utilization of acrochordid Snakes, with special reference to karung (Acrochordus javanicus)

We measured and dissected filesnakes (Acrochordus javanicus) collected for the commercial skin trade in southern Sumatra, to provide information on morphology and reproductive biology. In combination with published and original data on the other two living acrochordid species, this information enables us to compare these three taxa and to examine whether or not the existing commercial harvest of A. javanicus is likely to be sustainable in the long term. Acrochordus javanicus is superficially similar to the Australian A. arafurae, but is more heavy-bodied (almost twice the mass at the same SVL), with a larger head and a longer tail. All three acrochordid species show significant sexual dimorphism in bodily proportions (mass/SVL, head length/SVL, tail length/SVL), but sexual size dimorphism is less pronounced in A. granulatus than in the two larger species. Reproduction is seasonal in all three acrochordids, with ovulation around July and parturition five or six months later. Larger female A. javanicus produce larger litters, and about two-thirds of the adult females in our sample were reproductive in the year they were collected, Litter masses relative to maternal body mass (=RCMs) are higher in A. arafurae and A. javanicus than in A. granulatus. The similarity in RCM in A. arafurae and A. javanicus, despite a twofold difference in mean maternal mass, results primarily from the much larger litter size of A. javanicus (29.3, versus 16.9 in A. arafurae). Our data on the biology of A. javanicus, and on the ways in which this species is collected for the commercial skin industry, suggest that the current harvest is unlikely to seriously reduce wild populations. The relatively a seasonal precipitation regime in this area, the extensive (and largely inaccessible) habitat, the lack of specific and efficient techniques to capture snakes, the high reproductive output of the snakes and the low economic value of their skins, are some of the factors contributing to this continued sustainability. In contrast, the biology of Australian A. arafurae suggests that this species is poorly suited to commercial harvesting.