The apes may have had us surrounded, but we had them far outnumbered—which is, of course, the main rub in their existence.

In the scrum, the field’s best-known trailblazers jostled up against clusters of younger scholars. To an outsider, it looked like a generational handoff was under way. Earlier in the day, in reports about current research offered in a meeting room nearby, the next generation appeared to have left that timeworn argument about human/ape differences behind. They were fixed more intently on comparisons between non-human species, great-ape or otherwise, such as chimps versus bonobos, or chimps versus dolphins.

In the process, these young researchers have discovered evidence of remarkable behavior changes as chimpanzees come to live in ever-closer, and often fraught, proximity to humans. Their work tells a companion story to regular and worrisome predictions of great ape extinction. Up against swiftly changing conditions, chimps are managing to adapt in surprising ways.

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Gatherings of great-ape specialists border on the funereal. Four of six great-ape species (including both species of orangutans in Indonesia) are critically endangered, just one step away from extinction. The non-captive cousins of the two great-ape species in the center, Western Lowland gorillas and chimpanzees, are endangered, two steps from extinction. In recent decades, chimpanzee populations in Africa, estimated at 150,000 to 200,000, have been decimated because of expansion of palm-oil plantations (an industrialized form of agriculture), logging, hunting, climate change, and disease.

“We’re surrounded by doom and gloom,” Goodall said. But alongside these dominant trends were strands of a more hopeful counter-narrative, which she was eager to highlight. Making a beeline to an oversize electronic monitor smack dab in the middle of the hall, Goodall was joined by Tetsuro Matsuzawa, a primatologist from Japan best known for breakthrough research on instantaneous memory, and extraordinary spatial intelligence, among chimps.

Goodall and Matsuzawa met back at the inaugural Chimpanzees in Context conference, 30 years ago, at a time when great ape scholarship was marked by a sharp divide between experimenters in the laboratory and chimpanzee/bonobo researchers in African forests. Matsuzawa was one of the few scientists of his generation doing research in both settings, so he and Goodall helped bridge a troubled divide. Over the decades, they’ve grown quite close.

At the monitor, Lilian Pintea, the chief of conservation at Goodall’s institute in Washington, D.C., flashed a global overview of African landscape from 2010 to 2014. He pointed out the red shading, which indicated vast swaths where habitat had been lost or was threatened. He also showed back-to-back images from two villages adjacent to Goodall’s study site in Tanzania, revealing robust reforestation.