Young Siberian tigers, a male is captured in these photographs taken by infrared cameras last Sunday at Hunchun Nature Reserve in northeast China's Jilin Province. Experts identified the pair and two Amur leopards, both extremely endangered species, among photographs triggered by the animals' movements between March 26 and Tuesday at the 108,700-hectare nature reserve, which borders North Korea and Russia. China has a population of just 20 Siberian tigers but there are estimated to be an additional 100 on the Russian side.