This story is about chimpanzees found in eastern Senegal and western Mali. What makes them different from other chimps?
Fongoli chimps are revolutionizing the way we think about chimps because they live in a very different environment than other chimpanzees that have been studied. Other research sites are deep-forest sites, but Jill Pruetz [the scientist featured in this story] works with savanna-woodland chimps. The forest is thinner—half of the year there is no foliage because it gets so hot—and there is a lot of open ground. This habitat is similar to the one in which the original split between apes and humans occurred. With Jill's work we are going to get new ideas not just about chimps but the early hominids as they were adapting to new circumstances. That's very exciting.
How long were you in the field? Who was with you, and where did you stay?
We were on assignment for two months. It was Christine [Frans's wife and partner], me, a local helper, and sometimes we would team up with Jill. Occasionally we stayed with Jill—she established a compound in Fongoli village. But we also had a base in a town half an hour away, where we had access to electricity.
The chimps have a pretty large territory, about 24 square miles. Did you ever have trouble finding them?
Sometimes it was easy, sometimes it was not. Each day we needed to be in the forest before dawn, near the place where the chimps went to sleep the night before. They get up right at the crack of dawn and begin to move. Sometimes they are noisy and you can hear them, but other times they are stealthy. If we didn't connect with them right at dawn we could be crisscrossing the forest the rest of the day and never catch up with them. On some days the chimps would just go and go. On average we covered 10 to 15 miles a day. It was really hard work physically.
It was really hot, too, wasn't it?
Yes, at the end of the dry season it gets really, really hot, so we each had to carry a gallon of water on top of really heavy camera equipment. I had a 40-pound pack. This was a grueling assignment. In fact, it was one of the hardest things physically that I've done in a long, long time.
Because of the heat and the distance you had to travel each day?
For those reasons and more. We worked long hours—there were many days when we would be up at 3:30 in the morning and out until the end of the day. When the chimps would go to sleep, we would have to hike back out of the forest, make our way back to our own home base in the nearest town, and then we would have to take care of the equipment, off-load all of the images, have something to eat, and then set the alarm for 3:30 the next morning.
How difficult was it to photograph the chimps?
Working with chimps is just about the hardest thing I can imagine when it comes to wildlife photography, because their behavior is so ephemeral and fluid and the conditions are so hard. We had to find them, stick with them, and then I had to get into a position where I could actually do photography. The chimps are either invisible in a tree canopy, or they're doing something behind a tree trunk—and it's over in 10 or 15 seconds. Every five days or so I would have a meaningful photographic encounter. They are very keenly aware of your presence, and they don't like any attention focused on them. You have to be extremely astute and both very submissive and deferential. At the same time, you have to be really proactive—you have to anticipate what they do. It is just mentally and physically one of the greatest challenges I can think of.
Were there any chimps that were easier to photograph than others?
Some of them were more easygoing than others. After a while they became more accustomed to our presence. We were able to spend more time with some of the individuals, and we became very fond of them—like Mamadou, Ross the old guy, and Nickel with her firstborn baby. You start an assignment like this, and every chimp looks like the next one, but after two months they start to look like individuals. We had the distinct sense that at the end of two months they also recognized us as individuals and could differentiate us from other people.
What unique chimp behaviors were you able to photograph?
One of the behaviors that was really high on our list to cover was the one that caused shock waves in the media when Jill reported it. These chimps fashion weapons from tree branches and apply them as primitive spears or skewers to stab or impale bush babies [tiny nocturnal primates], which hide in tree holes. These chimps have figured out how they can use these sticks as weapons. They don't use them against each other; they use them in a way that is a step beyond the kind of tool use that we now know is commonplace among chimps.
How often did you see them using spears?
We only saw it about four or five times in two months. Sometimes it was only a couple of seconds, sometimes it extended over a longer period of time. But they do it in a tree canopy, so it was very hard to get a meaningful image out of it. Only half a dozen people in the world have observed this behavior directly. Christine and I and the writer are among those people. We were fortunate enough to capture it both on video and in stills—one of the images is in the story.
What would you like readers to take away from this story?
This is an important story. It is the next and newest installment that chronicles the intertwined history of what we know about apes and humans. Hopefully, the story will contribute not just to a broader and deeper sense of what chimps can do but also expand our understanding of chimps into a new part of Africa. Nobody has ever considered Senegal as a country where important things can be learned about chimpanzees. This can be the first step in the direction of coming up and applying a good conservation policy for chimps in West Africa.