"Almost everyone has a story about seeing one, it's such a mythical thing", says Mr Pilfold, of San Diego Zoo Global's Institute for Conservation Research.
After learning that several had been spotted in the Laikipia area of Kenya - the only area thought to have black leopards in all of Africa - he made a decision to investigate further and set up an expedition this January.
While albinism causes whiteness due to a lack of pigmentation, the genetic variation melanism results in an excess of dark pigmentation.
Wildlife photographer Will Burrard-Lucas managed it - and it's thought to be the first time anyone has captured a melanistic leopard on camera in Africa in 100 years. Typically in Africa and Asia that would mean a melanistic leopard - a black leopard.
A black leopard raised in captivity at the The Rhino and Lion Nature Reserve in Johannesburg.
Pilford was then told of a black leopard at the Laikipia Wilderness Camp in Kenya - an area not known for the creature.
Image copyright Burrard-Lucas Photography Image caption Dad? "As I scrolled through the images on the back of the camera, I paused and peered at the photograph below in incomprehension ... a pair of eyes surrounded by inky darkness ... a black leopard!" 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. I think when I started this project I didn't actually think I was going to be able to achieve a shot of a black leopard in Africa but that it is exactly what is here on the back of my camera.
"This is not just because leopards are extremely secretive and hard to see, but also because only a tiny percentage of leopards are completely black".
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He used specialist equipment including wireless motion sensors, high-quality DSLR cameras and two to three flashes.
Will captured a spotted leopard on one of the camera traps, which could be the black leopard's dad.
'This is what Will's photos and the videos on our remote cameras now prove, and are exceptionally rare in their detail and insight.
You don't need two black leopards to make one, but both parents need to carry the recessive gene for melanism.
"Coincidentally, our observations are very close to where the fantasy Marvel comic country of Wakanda is suggested to be located", he said.
Burrard-Lucas said in his release that he was always interested in black panthers.
"A black panther is basically a melanistic big cat".