Published: 2017-07-15 18:40:09 BdST
The startling photographs, taken in Tanzania's Ngorongoro Conservation Area, are the first evidence of such inter-species bonding between predators that are normally mortal enemies.
"There is no other recorded case where a big cat in the wild has suckled a cub belonging to another species," Luke Hunter, president of Panthera, a wild cat conservation group, told Reuters in a telephone interview.
The lioness, known locally as "Nosikitok", is well known to scientists as she is radio-collared and monitored by KopeLion, a Tanzanian conservation NGO supported by Panthera.
The photos were taken on Tuesday and Hunter said that, as of Thursday, Nosikitok had returned to her pride some distance from where she was nursing the leopard cub, "so we are not sure what is going on now".
"It's possible the mother leopard retrieved the cub from what was a temporary lioness day care, but we just don't know," he said.
Photo: Joop Van Der Linde/Panthera/Handout via Reuters
Hunter said Nosikitok has her own litter of lion cubs about the same age as the leopard cub, estimated to be three weeks old, and this could be a reason.
"She is physiologically primed to take care of baby cats, and the little leopard fits the bill — it is almost exactly the age of her own cubs and physically very similar to them."