A leopard has been caught on camera in snow leopard territory, high on the Tibetan plateau, for the first time in a discovery that has alarmed conservationists trying to save the latter.

There are fears that, as the climate warms, leopards will increasingly compete with their endangered cousins.

Snow leopards are classed as endangered after losing at least 20 per cent of their population in just 16 years due to habitat loss, poaching and a lack of prey to eat, according to the International Union for Conservation of Nature (IUCN).

The global population is estimated at between 4,080 and 6,590.

Leopards are “widely distributed” in Africa and Asia, according to the IUCN, but are themselves classed as “vulnerable” with evidence of dramatic reductions in their populations because of persecution, hunting, loss of habitat and other largely human-caused factors.

They normally inhabit forests, while snow leopards tend to be found above the tree line.

Byron Weckworth, China programme director at conservation group Panthera, told BBC News that the latter were losing territory as the temperatures rise.

“In a changing climate, we expect the tree line to move up the slopes and that's encroaching into the snow leopard's habitat,” he said.

“The bigger threat is the snow leopards' habitat loss and its fragmentation.”

The ordinary leopard was caught on a camera trap in China’s Qinghai province in July last year, when the same camera also filmed a snow leopard.

It is unclear how the two species will interact. Some local people believe the two types of cat have mated, but Mr Weckworth said it was unlikely they would be able to produce any offspring because they are too far apart genetically.

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Koustubh Sharma, an expert with the Snow Leopard Trust, said: “How are these two cat species already managing to live together — or will the interface be difficult when their habitats are changing with climate change?"

“The pictures from our camera trap make these questions more relevant and pressing.”

The situation echoes the increasing interactions between grizzly and polar bears as temperatures warm in North America.