Scientists estimate that there are only 84 highly endangered Amur leopards remaining in the wild across their current range in Russia and China. This new figure was reported in the journal Conservation Letters by scientists from China, Russia and the US.

They combined forces to collate information from camera traps on both sides of the border of China and Russia. Because there are no records of leopards in other parts of its former range, this estimate represents the total global population of this subspecies in the wild, they say.

Biologist Anya Vitkalova, from Land of the Leopard National Park in Russia, said: "We knew that leopards moved across the border, but only by combining data were we able to understand how much movement there really is."

Despite the movement, there were differences in population dynamics in Russia versus China. Leopards are recolonising habitat in China by dispersing from the Russian side, where leopard numbers appear to be close to the maximum that can be supported.

Dr Dale Miquelle, a co-author and Tiger Programme Coordinator for the Wildlife Conservation Society, said: "This first rigorous estimate of the global population of the Amur leopard represents an excellent example of the value of international collaboration."