The total extent of the animal's population decline is still unknown, San Diego Zoo said in a statement. But several factors have sharply reduced their numbers, including hunting, habitat loss, competition for prey, and conflict with livestock and farmers.
Pilfold is part of a team from the San Diego Zoo working with local partners, including the Kenya Wildlife Service, to monitor leopard populations in the area and help preserve the species.
He marveled at the coincidence of the location of an animal that's also called the black panther, the title of one of last year's biggest movies.
"Coincidentally, our observations are very close to where the fantasy Marvel comic country of Wakanda is suggested to be located," he said.
Black panthers refer broadly to any melanistic leopard, jaguars and other big cats.
It started in the local community
Ambrose Letolulai, a local leopard conservationist who was part of the project, was speaking with the community as part of efforts to better understand the human wildlife conflict. In one conversation in September, he interviewed an elder who told him about the challenges they were facing with ordinary leopards killing livestock in the region. The elder told him he had seen a black leopard, which he said are known in the Samburu language as "calf killers." The team then set up a camera trap in that location.
"I first heard about the black leopard when I was growing up from the stories of elders, but I didn't believe it at all until I saw it myself," he told CNN. "As a local, people have always been talking about the black leopard."
Kenyan conservationist Paula Kahumbu said there have been many unconfirmed sightings of black leopards, but this is the first time one has been proven.
"Despite many challenges in the sector, Kenya's wildlife continues to awe and inspire the world," Kahumbu said. "I hope that this rare find persuades the authorities that we must balance conservation with development to protect our spectacular and mysterious species."
Kahumbu congratulated Letoluai for helping spearhead the international project. "I ... hope it inspires a new generation of Kenyan wildlife scientists," she said.
CORRECTION: The story has been updated to correct the spelling of conservationist Ambrose Letoluai's last name and to update a quote attributed to Letoluai to clarify the source of the information. An earlier version of this story contained a quote incorrectly attributed to Paula Kahumbu. It has been removed.