The Last Leopards in Indochina: Unique Predators on the Brink of Extinction
February 9, 2018
February 9, 2018
Eastern Cambodia’s Indochinese leopard can take down banteng, a rare wild cattle species weighing up to 800 kilograms—a prey size more typical for lions and tigers, and more than what any other leopard population can handle.
Our research showed important aspects of the population and ecology of the Indochinese leopard, a genetically distinct subspecies that historically occurred throughout all of Southeast Asia, but that has exhibited a dramatic range collapse, leaving them in only 5% of their historical range. The study site, in the open dry forests of eastern Cambodia, contains the last remaining population of Indochinese leopards in all of Cambodia, Laos, and Vietnam.
Our results showed the leopard density was only one leopard per 100 square kilometers—one of the lowest densities ever reported in Asia. Alarmingly, the density declined 72% over five years, indicating extinction could be around the corner. After ruling out factors like differences in methodologies and prey declines, we concluded increased poaching, especially by indiscriminate snaring, was to blame for the dramatic decline.
We found the subspecies’ main prey was banteng, the rare species of wild cattle that weighs 600-800 kilograms (1,320-1,760 pounds). These results were completely unexpected, because no other leopard population in the world was known to have a main prey weighing more than 500 kilograms (1,100 lbs). In fact, the previous research showed the preferred prey for leopards was only 10-40 kilograms, such as small deer.
Also unexpected was that male and female leopards had completely different diets: Males consumed mostly banteng; females, mostly muntjac, a small deer that weighs 20-28 kilograms (44-62 pounds). Although male leopards can be up to 50% larger in body size than female leopards, and therefore capable of killing larger prey, no previous study found such a large difference in prey size between the sexes.
Males’ food choice of banteng was likely due to the extirpation of tigers on the site in 2009. Tigers kill and displace leopards, and previous research showed leopards tend to kill smaller prey in the presence of tigers to avoid competition. After tigers were wiped out in the area by poaching, the larger male leopards were allowed to expand their niche to include predation on the largest herbivores, whereas the smaller females stuck with smaller and less dangerous prey such as muntjac.
Our results suggest that when tigers become absent from an area, leopards are adaptable enough to change their behavior to fill a similar predatory role as tigers in the ecosystem.
As a result of our paper, Panthera has increased the monitoring of this important leopard population by conducting more camera-trap surveys and increasing the areas where leopards are surveyed. We are working with our collaborators, WWF Cambodia, WildCRU, and the Ministry of Environment, to help strengthen environmental laws in eastern Cambodia to develop strictly protected core zones and increase fines from poaching.
We are also raising money to help increase effective enforcement, which includes using PoacherCams and providing technical assistance for enforcement activities to better protect endangered leopards and their prey in this unique but vulnerable ecosystem. Our short-term goals are to stabilize the leopard population from further decline and, eventually, to recover the population throughout the eastern plains landscape of Cambodia.