At the University of Liège, Sarah Tossens is a graduate student of Dr. Marine Drouilly, a Panthera scientist who specializes in leopards. Learn more about her journey deep into the jungles of the Republic of the Congo to monitor the ecological roles of leopards and golden cats in this densely forested landscape.
I will always be fascinated by the rainforest: the sight of trees towering over dense vegetation, the diversity of life forms and the musical symphony characteristic of these magnificent forests. But once on the ground, conducting research in the rainforest can be more of a challenge.
The vegetation’s thickness makes wildlife monitoring difficult. This is especially true for cryptic species that exist at low densities and are particularly understudied, like tropical wild cats.
Monitoring leopard and golden cat populations is crucial to improve our knowledge of their ecological role (their position at the top of the food chain likely regulates prey populations, which indirectly affects plant species) and to put in place appropriate measures for their conservation. This was the objective of a project I carried out last summer with my technical assistant Marius Ruwet in the Republic of Congo. We installed 252 camera traps in an FSC-certified forest concession and national park before the start of the rainy season.
Not only must researchers navigate through thick vegetation, tropical forests present other challenges. They would not be complete without insects. A great deal of patience is required when gnats are constantly flying in your ears and eyes from sunrise until nightfall. After that, you must be cautious of fascinating unpredictable and sometimes dangerous animals. Due to the thickness of the undergrowth, we approached buffalo, elephants and chimpanzees without even noticing their presence until we were only a few meters away. These moments are memorable — and a great reminder to always be on the lookout.
I will always remember a day in Nouabalé-Ndoki National Park, when suddenly, the vegetation started to swarm all around us a gorilla cries soaring in the trees just above us. After a few delightful seconds, reality catches up with you and the only question that matters then is: "Where is the silverback?” As the dominant male, his role is to protect the entire group and his reproductive success with the females depends on it. When a few seconds later, a baby gorilla slipped from a trunk in the middle of our team, emitting a cry of distress; we knew we might be in danger. Fortunately, we were accompanied by trackers who knew the forest inside and out. They always ensured our safety, telling us to crouch and make maximum noise until the silverback would leave. What a narrow escape but incredible memory!
As for the leopard and the golden cat, it's rare to see them in the forest. The best place to spot them is on a trail. Leopards frequently use old logging roads or elephant tracks to move more quickly through the dense rainforest. Here we find the best spots to set up our cameras to monitor signs of these cats, like spoors and scats.
One day, we were walking along an old logging road where we had found some leopard and golden cat tracks a few days earlier. We discovered fresh leopard prints about two kilometers from our starting point. But the further we went, the more intrigued we became — the tracks exactly followed a path we had taken three days earlier. In the end, we could follow this individual for eight km until they disappeared into the dense vegetation, a few meters before the end of our last walk.
Even if these species are hard to study in their natural environment, camera trap surveys have repeatedly demonstrated robust conservation utility. This keeps us motivated and passionate about what we do. Despite the challenges (and the number of swamps to cross, which increased as the rainy season approached), traveling in the forest and learning so much from our guides inevitably made us feel in awe of the forest.
On our last day in the field, this incredible feeling overwhelms you. When we returned from the field, a long shadow with a curved, bushy tail crossed our path about 30 meters before us. One might wonder if the leopard was tracking us all this time rather than the other way around...