Karanth went on to study mechanical engineering and then bought a plot of land to farm near Nagarhole so he could be an amateur naturalist in his spare time. In 1984, he entered a wildlife management training program at what is now the Smithsonian Conservation Biology Institute in Front Royal, Virginia. Karanth earned a PhD from Mangalore University studying tigers inside Nagarhole. He now works for the New York-based Wildlife Conservation Society (WCS), combining the cool objectivity of an engineer with the passion of a local boy who never tired of looking for tigers. Since he began monitoring the population in 1990, tiger numbers in Nagarhole have climbed from fewer than 10 individuals to more than 50. More important, the park is a source of young tigers: Cubs born here are leaving the park and repopulating the surrounding forests. “There are now 250 tigers in this region,” Karanth says. “If we do everything right, we can have 500.”
“You have to be able to measure tiger populations with confidence, and Karanth has developed the whole tool kit to do this,” says John Seidensticker, head of the Smithsonian’s Conservation Ecology Center and one of Karanth’s early mentors.
Each year after the summer monsoons, Karanth and his team blanket the forest with hundreds of camera traps. When an animal walks past a trap, infrared sensors trigger cameras on both sides of the trail. Every tiger has a unique stripe pattern, which Karanth uses to identify individuals and estimate how many tigers live in Nagarhole at any time. He has collected more than 5,000 tiger photographs.
He has found that one out of four adult tigers in the park dies or disperses into the surrounding forest each year. In the past four years, he says, he documented 40 deaths in the area that includes Nagarhole, Bandipur and several other reserves. But he’s not worried. “If reproduction is up,” he says, “this is not a problem.”
What affects tiger reproduction? The answer might seem simple, but it took Karanth nearly ten years to collect the data to confirm a direct relationship: The more animals available for tigers to eat, the more they reproduce. “The forests were empty not because the tiger had been hunted out, but because their prey had been,” Karanth explains.
The realization has significant implications for how to protect tigers. Many conservation authorities focus on stopping big-game poachers, who kill tigers and sell the body parts for high prices on the black market. (Tiger bone, for instance, is promoted as a cure for arthritis and malaria.) But Karanth’s findings suggest that local villagers who hunt deer and other animals have had a larger impact than wildlife traffickers on tiger numbers. Now 120 men, armed with little more than sticks, patrol Nagarhole looking for illegal snare traps.
Early one morning, Karanth and I left the safety of a WCS work jeep and stepped into an environment where humans aren’t at the top of the food chain. A splotch of red paint on a tree marked the start of a two-mile trail we would follow through the forest looking for wildlife. Even the smallest noise or movement sent me jumping.
Karanth scouted straight ahead while WCS technician M.N. Santosh followed a few paces behind, looking for movement on either side. The biologists are armed with nothing more than a clipboard, a compass and a range finder (a glorified laser pointer for determining how far away something is). Based on the number of animals they find and their distance from the path, the biologists can estimate prey densities.
I struggle to keep up, trying not to snap any branches beneath my feet. My effort to tread lightly is partly so I don’t scare off any animals and skew their survey results. It’s also self-preservation. Nagarhole is home to one of the highest concentrations of forest-dwelling Asian elephants. The giant pachyderms have poor eyesight, are easily spooked and can charge through the forest faster than any human can run. Roughly 30 people die each year in the region as a result of elephant tramplings. Tigers, in comparison, have killed two or three here in the past 45 years.
Ten minutes into our hike, I step ankle-deep in dung so large it could come from only one animal. Something large crashes through the brush a short distance away. “Elephant!” Karanth whispers with a glint in his eyes that seems more mischievous than worried.