Tracking Elephant Migrations

Field Report From Africa
Dr.William Karesh(October 6, 1998)
Click to view update (October 12, 1998)

CENTRAL AFRICA - Steve Blake, a WCS field biologist, and I are in the forest of the south-eastern tip of the Central African Republic. If we hiked through the jungle for a few miles we would be in the Congo Republic and a few days in the other direction would land us in Cameroon. We've been here in the Dzanga-Sangha National Park for almost two weeks with the hope of placing radio collars on forest elephants. Steve has been studying them for a couple of years across the border in the Congo and is interested in determining their migration patterns in the jungles here. My role, as the field veterinarian for WCS, is to anesthetize the elephants so they can be fitted with collars containing the radio tracking devices. The collars will use the Global Positioning System (GPS) satellites to determine the longitude and latitude of the elephant. Each unit will then store the information until Steve uses a radio to communicate with the collars and download the data. With the migration information, better planning can be undertaken in areas surrounding the national parks to protect the elephants. This system has never been used before on forest elephants and the information to be gathered is critically needed to understand the ranging patterns of elephants in the central African forests.

Of course, the real world is always more complicated than the best laid plans, and despite our remoteness here in the jungle, we couldn't be closer to the real world. Besides little difficulties such as paperwork problems, a severe fuel shortage due to fighting in nearby Congo/Zaire, and fouled short wave radio communications, the elephants are making the work incredibly difficult. Due to years of poaching, the elephants are very wary of humans in the forest. Their keen senses of hearing and olfaction frequently allow them to detect us before we know they are nearby. Helping us find the elephants are a group of Bayaka men, one of the many "pygmy" clans of central Africa. Being true people of the forest, our Bayaka guides have made all the difference in finding and stalking the elephants. I found myself within twenty to thirty yards of elephants close to a dozen times the last few days.

But getting close is not enough, I have to dart them with a drug dart. In the forest, the leaves and branches easily block the flight of the dart, so I have to get fairly close to find a window through which to shoot the plastic syringe. So far, we have been lucky and most of the elephants have run away when we surprise them. Their other alternative, of course, is to try and neutralize our offensive, so to speak. They can do this easily since they can outrun us in the swampy forest. Sometimes the elephants are out in one of the few marshy clearings, or a "bai" as they are called here. Unfortunately, in the middle of the bais they are frequently too far away for my dart to reach them. Also, unfortunately, they prefer to use the bais at night, but darting in the dark is too dangerous for both us and the elephants.

Today, we were finally successful in immobilizing and collaring an elephant. She was a young adult about seven to eight feet tall at the shoulder and tagging along with her was a five-year-old calf. She had come to the edge of a bai to drink the mineral which water that springs up along the stream that runs through the marshy plain. By sneaking behind the trees and bushes lining the bai, we were able to get within forty yards of the pair. Using an air-powered dart gun, I was able to shoot a lightweight plastic and injected the anesthetic in the muscles of the adult females thigh. Startled by the dart and the poof-sound of the gun, she turned immediately to determine the source. Rather than charging us though, she just stood in the knee-deep water as if in a quandary. A few minutes passed before she waded to the edge of the bai and walked into the forest with her calf by her side. Using her footprints and the mud she rubbed on the thick underbrush, we followed slowly behind the two of them. The drug would take at least ten minutes to take full effect and we neither wanted to scare her and cause her to run deeper into the forest, or startle her and provoke a charge. Twelve very long minutes elapsed before she laid down. Her youngster staid by her side until she saw us approach and then ran off to a safe distance in the forest. The female began to stand again but I was able to sneak up behind her and inject a little more drug with a regular syringe to make her fully relax and lay down completely. While I monitored her under anesthesia and took a small blood sample for health evaluations from one of the massive veins that act as a cooling panel on the back of elephants' ears. She appeared to be in good condition, well muscled and lean., no scars or recent injuries. Her foot and a half long tusks were undamaged and worn evenly to form sharp points, the perfect tools for stripping bark off trees. Her skin was not smooth but at the same time, soft to the touch and warm. Her regular, deep breaths blew through her relaxed trunk with the hollow sound of air rushing through a huge plastic tube.

Steve and the rest of the team quickly fitted her with the tracking collar. They measured the seventy five inches around her neck and adjusted the collar for a custom fit. A small gray elephant-proof antenna rides on top of the three-inch-wide collar made of rubberized machine belting. Weighing a little more than two pounds, the electronics and battery package is mounted on the bottom of the collar to serve as a counter-weight. This prevents the antenna from swinging around and hanging underneath where the massive body of an elephant would interfere with the radio signals.

As soon as we were finished, I gave her an intravenous injection of another drug that completely reverses the action of the anesthetic. The team had packed up our gear and moved away into the forest. In three minutes, she quietly righted herself and got to her feet. She paused briefly and then turned and walked into the thick underbrush where her calf was waiting. The sun was about to set and we still had an hour's hike through the forest back to camp. But we did not leave the spot without realizing that we had just put the first GPS collar on a forest elephant.

Update (October 12, 1998)
Steve, I and the Bayaka trackers searched for elephants for another three days in the forest. Finally today, we found a massive bull elephant standing alone in a bai drinking the mineral rich water. We heard his snorkeling, like a giant water cooler bubbling before we approached the small clearing. I was able to crawl through the mud behind a fallen tree and position myself within forty-five yards him. He was blowing air to excavate a hole in the stream bed with four feet of his trunk and then filling it with water. Raising back his head, he would then curl his trunk around, put it in his mouth and drink the water. He was facing me directly so I couldn’t fire a dart at him. We had maneuvered ourselves to be down wind so he could not catch my scent and as long as I didn’t make any noise like breaking dried leaves or twigs and stayed hidden, I would go undetected. Finally he turned sideways and I managed to shoot a dart below his shoulder. He paused and looked in my direction, but rather than charging, he turned and lumbered into the forest on the opposite side of the stream.

We followed him into the forest and found him standing almost motionless two hundred yards later. He was still awake and looking in our direction. After waiting fifteen minutes for the drug to take effect (or hopefully so) he still had not laid down so I crept to within twenty yards and darted him with second dose. Five minutes later he laid down, but could still move his head and legs. Giving him an additional dose intravenously provided the relaxation he finally needed and we got to work fitting the radio collar on him.

He was a massive bull, roughly thirty-five years old. His tusks were thick and. like forest elephants, not as curved as bush elephants of the grasslands of eastern and southern Africa. They were about forty inches long and over a foot in circumference at their bases. He probably weighed seven or eight thousand pounds and was in beautiful condition. We quickly got the GPS collar customized to fit around his neck (close to ten feet long) and secured it in place. Within three minutes of receiving the reversal drug intravenously in one of the huge veins on the back of an ear, he stood and walked off into the forest.

Over the next two years, Steve will use an airplane* once every month or two to contact the collars and download the information they are collecting on the elephants movements. No one knows if the elephants here are traveling into the neighboring countries of Congo and Cameroon and how often they leave the park boundaries here in the Central African Republic. If all goes well, this trial run of using GPS collars on forest elephants will begin to unravel the mystery of how the forest elephants of this region of the continent depend on their shrinking home.

*Steve Blake's grant and the airplane used have been donated by the U.S. Fish and Wildlife Service African Elephant Conservation Fund

This project resulted from a collaboration between the Wildlife Conservation Society, the World Wildlife Federation, and Save the Elephants.

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