Moscow, Mar 16 (IANS/RIA Novosti): The population of the Amur leopard has grown by half since 2007 and the cats have expanded their habitat as far as North Korea, the World Wide Fund for Nature (WWF) said.

But at an estimated 48 to 50 animals in Russia, including four to five cubs, it remains critically endangered and the least populous of all leopard subspecies, the fund said.

Environmentalists were unable to take a census of the big cats for several years, because the population is counted by their paw prints in the snow. No lasting snow was seen since 2011 in their habitat, an area 5,000 square km in Russia's far eastern Primorye region.

The previous census in 2007 put the number of Amur leopards at between 27 and 34, which many experts said at the time is not enough to ensure continued reproduction of the subspecies.

But a conservation drive spearheaded by the WWF and supported by the Kremlin improved the situation.

Now the Amur leopard is expanding its range to territories both north and south of its current habitat, reaching the Russian-North Korean border, where no big cats were seen since the last century, the WWF said.

Even the leopards' appearance is diversifying -- a photo distributed by the WWF showed an Amur leopard with white paws - a rarity among the yellow-and-black cats.

"The White-Gloved Leopard", as the creature was identified by the WWF, encroached on the territory of the 18-year-old cat nicknamed Fat Guy, whose current whereabouts are unknown.

The total number of Amur leopards may be even higher than 50, because between five and 11 cats also supposedly live in northern China, where no census was held.

Environmentalists hope to increase the population to 70 to 100 cats, which would ensure its stability, said Yury Darman, head of WWF's Amur branch.

At its current size, the population of the Amur leopard can be wiped out by an epidemic.

But whether the WWF can reach its goals remains open to question, given that the cats' food supply is depleting due to mismanagement of deer parks in the area, the report said.

Moreover, the number of Amur tigers sharing the territory with the leopard has doubled to 23 animals since 2008, the WWF said.

Tigers compete with the leopard for food and are not above killing a smaller cat in a standoff over a deer or boar corpse.