Weights of gaur (Bos gaurus) and banteng (Bos javanicus) killed by tigers in Thailand

The primary prey of tigers across much of Southeast Asia has been
depleted, reducing the ability of already limited habitat to support
tigers. To better understand the extent to which two of the largest prey
species, gaur (Bos gaurus) and banteng (Bos javanicus), contribute to the
tiger’s diet, we estimated the average size of these species killed by
tigers. This information is needed to more accurately calculate biomass of
these species in the tiger’s diet and to devise strategies to increase
tiger carrying capacity where habitat is fragmented and limited in
west-central Thailand. We used temporally clumped locations of 24
satellite radio-collared tigers to identify their kill sites and obtained
mandibles from 82 gaur and 79 banteng. Kills were aged by teeth eruption
sequence, sectioning the M1 molar and counting cementum annuli. Of all
gaur killed, 45.2% were adults; of all banteng killed, 55.7% were adults.
The average weight of banteng killed was 423.9 kg, which was similar to
the 397.9 kg average weight for gaur. The mean weight of both prey species
is 3.5 to 4.5 times greater than the predicted 1:1 preferred prey to
predator ratio. In the absence of medium-sized prey, killing these larger
animals may be especially critical for female tigers provisioning nearly
independent young when male offspring are already larger than the mother.
This is the first study to present data on the average weights of gaur and
banteng killed in Southeast Asia and these results suggest that these are
key prey species to target in tiger prey recovery efforts.