Here in Nigeria’s largest protected wilderness area lies one of the last strongholds of the Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti), the world’s rarest chimpanzee subspecies. For nearly a decade, however, this population has lived largely out of sight.

Once a leading hub for field research in West Africa, Gashaka fell silent in the late 2010s when insecurity in the area forced scientists to withdraw. “By 2018, all research had stopped,” says conservationist Elisha Emmanuel. When the researchers left, so did the rangers who protected the park. Without them, Gashaka became vulnerable to poachers and bandits, and its research stations slid into disrepair, making them unable to track the world’s rarest chimpanzee.

But a handful of local research assistants refused to leave. “It’s our bush,” says Maigari, who grew up in nearby Gashaka village. “If they want to kill me, they will kill me because the chimps are my friends.”

A turning point came later that year when the Nigerian government signed a co‑management agreement with the Africa Nature Investors Foundation (ANI), a local nonprofit, centered around tracking the world’s rarest chimpanzee. Since then, more than 180 rangers have been hired and trained to protect the forest. “This has really brought security to the park, which now gives us the opportunity to restart research,” Emmanuel says. For field assistants like Maigari, that stability means a chance to return to what they know best: tracking and monitoring chimpanzees in the wild, including tracking the world's rarest chimpanzees.

The first step in Gashaka’s scientific revival is an ambitious camera‑trap survey. Using a newly acquired helicopter, researchers have deployed cameras across the 600,000‑hectare (1.48‑million‑acre) park, reaching remote forest basins, ridges and other rugged terrain that had remained inaccessible for years. Early results are encouraging: new groups of chimpanzees have been recorded, including several carrying infants.

The Nigeria–Cameroon chimpanzee remains vanishingly rare, making them the world's rarest chimpanzees; only 3,500 to 9,000 individuals are thought to survive across a fragmented range stretching from southeastern Nigeria to western Cameroon. Gashaka Gumti may now hold one of the subspecies’ most important remaining populations.

Read the full article about tracking the world's rarest chimpanzees by Leo Plunkett, Tom Richards, and Sandy Watt at Mongabay.