Abstract:
Fewer than 3,500 tigers (Panthera tigris) remain in the wild. Habitat loss and fragmentation, and
depletion of prey are key factors contributing to their decline, prompting investigations on prey
requirements needed to sustain their dwindling populations. To estimate prey requirements from
consumption rates the Non-Consumed Portion of a carcass (NCP) or degree of carcass utilization
is required, as depending on prey size part of the kill might not be consumed. Because NCPs for
tigers have never been systematically estimated, the aim of this study was to develop a model to
calculate NCPs based on prey body mass, and to determine whether the NCPs used in current
tiger literature were accurate. Additionally, we applied the model to two tiger reserves to test if
our results improved prey requirement estimates calculated with current NCPs. The study took
place at Laohu Valley Reserve (South Africa), where four male and five female tigers were fed
fresh carcasses of six ungulate species. Each prey carcass was weighed prior to feeding to tigers
and once abandoned, the remains were weighed allowing the weight consumed minus the
gastrointestinal contents to be calculated. We observed a strong positive relationship between
prey body mass and NCP. For large prey, prey requirement estimates obtained with the NCPs
yielded by our model were very similar to those obtained with the NCPs used in current tiger
literature. However, differences increased for smaller prey, and for those species that comprised
a high percentage of the tiger diet. In summary, we provide a model to calculate NCPs based on
prey body mass, and demonstrate the importance of using specific values of NCPs in calculating
prey requirements from consumption rates. These results could be useful for other large
carnivores, as well as for calculating feed portions for large predators in captive settings.
