Looking for Jaguars in the Night

It’s late October and the third week I spent at our camp in the Espinoza logging concession trying to trap and radio collar jaguars, pumas, and tapirs. Located in the southeastern Peruvian Amazon, this concession was certified by the Forest Stewardship Council (FSC) few years ago for its sustainable, low impact logging.

A network of dirt roads cover the area like a spider’s web, but a locked gate with a guard prevents access to outsiders, and hunting is strictly prohibited. These roads provide us with the ideal setting to study species that are elusive and range over hundreds of square miles. After a camera trap survey in 2010 showed that concession harbors a high density of jaguars and other species, we spent the last three years radio collaring large cats to get more information on their ranging behavior, habitat preference, and social interactions.

The goal is to determine what size of an area is needed to protect healthy populations of these top predators and what impact a sustainable logging operation has on these and other species.

Forest Adventure

It’s already dark when we head out to check our traps for the third time today. The traps are safe for the cats, and we check them frequently to minimize stress for the animals (and ourselves!). We get into the pickup truck with Samia on the wheel, Alfonso as a copilot and me standing in the back with a dart gun looking out for tapirs crossing the road. One has to be quick to dart a tapir this way as they are easily spooked and quickly disappear into the forest, but just a few days ago we were able to catch the first one and we are hoping to get a few more before the end of the field season.

Our large cat traps are set along different logging roads with one to two miles between each trap. The poor road conditions means it will take about two hours to check all of them. The first couple of traps are undisturbed, so we keep going; the last one is still a way ahead. At the last stop it is my turn to check the trap.

Everything looks normal, no sign of any disturbance. I bend down to re-arrange a few things and when I look up again, I see two large eyes staring at me, shining in the light of my headlamp less than15 feet away. I immediately know that it is a jaguar! My heart starts pounding and I slowly get up and walk backwards, keeping my light fixed on it. Fortunately the jaguar is as surprised as I am and decides not to go after me. I make it back to the truck safely, my legs shaking with adrenalin.

We decide to wait for a little bit, hoping for the cat to step into one of the traps. After ten minutes it’s time to check again. This time, armed with a stick for reassurance, I head back into the forest.

I immediately see the eyes again, but the jaguar was caught in the trap. Excited I run back to let the others know.

Alfonso, our veterinarian, prepares the dart that he delivers with a blow pipe. Ten minutes later the cat is sound asleep and it’s time to get to work. It’s a large older male, with worn down teeth and weighing over 180 pounds. As an experienced field team, everybody knows what to do; fit the radio collar, take measurements, asses the animal’s health status, and take samples for DNA analysis. The collar is equipped with a GPS unit that will record the cat’s location every 15 minutes for the next year; after which it will automatically release itself and we will retrieve it to download the data.

We have to work quickly as the anesthesia only lasts for about 45 minutes. Once done, we watch from the car as the cat starts moving his ears, then lifts up his head looking around, gets up, and quickly disappears into the dense forest. We will be checking on his radio signal over the next couple of days to make sure everything is okay. Happy about another successful capture, we head back to the camp for a short night sleep before getting up at 5 a.m. to check the traps again.

By Mathias Tobler, Ph.D., Senior Researcher, Applied Animal Ecology
San Diego Zoo Institute for Conservation Research.