Abstract
Among the 91 species of native mammals found in Sri Lanka there are 14 species in the order Carnivora. Of these, four are members of the Felid family: the Sri Lankan leopard (Panthera pardus kotiya), the jungle cat (Felis chaus), the fishing cat (Prionailurus viverrinus) and the rusty-spotted cat (Prionailurus rubiginosus). The Sri Lankan leopard is the largest of four wild cat species recorded on the island of Sri Lanka. In this study, the causes of death were investigated in leopards that died at the Uva and Southern wildlife regions from January 2011 to March 2013.
Thirteen leopard necropsies were conducted: three of them from the Ratnapura District belonging to the southern wildlife region and the rest from areas associated with the Yala National Park, belonging to the Uva wildlife region. During the postmortems, all the morphological features and measurements were recorded along with the data of gastrointestinal content as well as internal and external parasites. Animals were weighed and age estimations were done based on the size and weight of the animal, morphological features, dentition and tooth wear characteristics.2,3 The animals ranged from 5 months to over 10 years of age. The sex ratio was 11:2 male to female. The three animals from Ratnapura were adult males weighing over 60 kg that lived near the tea plantations. Causes of mortality for them were gunshot wounds, poisoning and internal organ damage from snares, respectively. The sex ratio of animals that died in the Yala National Park is 8:2, male to female. Out of these animals, 8 deaths occurred in the Yala block 1, one in the block 4 and the other one in the Babawa area (1 km outside the Yala block 1). The animals that died in block 1 ranged from 5 months to 10 years of age. The causes of mortality included one from a vehicular accident, three from intra-species attack, one from an explosion in the oral cavity from a gun powder trap, and one each for starvation, wild boar attack, and snare trap. The animal in block 4 was a pregnant animal with 3 fetuses that died due to a vehicular accident. The animal that died in Babawa was due to poisoning.
In this study, the mortality rate for males was higher than for females. This sex-dependent mortality finding has been seen in other studies.1 The Sri Lankan leopard lives both within and outside the protected areas. Those outside are under even more pressure from human interference. Likewise, this study shows that the majority of leopard deaths were due to human interference and appears to be the leading cause of the diminishing leopard population outside the protected areas. Intra-species aggression accounted for the second largest number of deaths after human-related mortality. As leopards are known to defend their territories from same-sex intruders, this may be considered a natural process at places like Yala block 1, where there is a high population density of leopards.
Literature Cited
1. Balme GA, Hunter LTB. Mortality in a protected leopard population, Phinda Private Game Reserve, South Africa: a population in decline? Africa Ecological Journal. 2004;6:5–11.
2. Balme GA, Hunter L, Braczkowski AR. Applicability of age-based hunting regulations for African leopards. PLoS ONE. 2012;7(4):e35209. doi:10.1371/journal.pone. 0035209.
3. Stander PE. Field age determination of leopards by tooth wear. Afr J Ecology. 1997;35:156–161.