When wild chimps encounter humans, they typically flee in panic—understandable given that the relationship between our two species has often been one of prey and predator. This reticence around humans is part of what makes wild chimp research so difficult. Before the animals can ever be studied, they must learn not to bolt at the sight of a person, a process of habituation that requires many years of diligently trailing the animals around the forest.
One thing unhabituated chimps aren't ever expected to do when they run into humans is call over all their buddies. But that's exactly what happened. Another chimp showed up a moment later. Then a third. Then a fourth. Manic yelping enveloped the canopy. Morgan and Sanz may have been the scientists, but it was the chimps who were behaving as if they'd made some great discovery. The party sat on limbs above the camp all evening, watching excitedly as a fire was started, tents were pitched, and dinner was prepared.
"I thought, This is what loggers must have seen all through central Africa, and poachers shot them all," says Morgan, 40, a conservation fellow with Lincoln Park Zoo and the Wildlife Conservation Society (WCS). Morgan has spent the better part of the past ten years living with Sanz in the Goualougo Triangle study area, a pristine 147-square-mile nub of lowland forest overlapping the Ndoki and Goualougo Rivers in northern Republic of the Congo. He and Sanz were awed by the close encounter, but they began to wonder when it might end. It was getting dark. Where were the chimps going to nest?
"Sure enough, they built their nests directly over our tents," says Morgan. "I was like, This is great! But our trackers were like, No way, man, this is very bad news." All night long, the chimps hollered from the trees, shook branches, urinated and defecated on the tents, and hurled sticks at the team. Nobody slept. At daybreak the chimps came down from their perches and watched from the forest floor as the group built up the fire and made breakfast. Then, quietly, one by one, the chimps slunk away and vanished into the thick underbrush.
When tales of the "curious" chimps of northern Congo—uncorrupted by misdealings with humans and apparently fully ignorant of our existence—were first reported in this magazine in 1995, more than a few primatologists scoffed. "People were like, Curiosity: Hmmm, how do you define that?" says Sanz, 34, now a professor at Washington University in St. Louis. "Poor Dave, when he first told me about these chimps, even I didn't believe him." Though there had long been scattered anecdotes of fearless central African apes who trailed explorers around the jungle and behaved as if they'd never seen a human before, it beggared belief that there could be an entire forest full of them.