In December, 2002, a photo taken during camera-trap surveys organized by the Wildlife Conservation Society showed a leopard wearing a radio-collar. Scientists from WCS and the Russian Academy of Sciences realized that they must already know this leopard from capture and radio-tracking activities conducted between 1994 and 1996, and knew that they could identify this animal from the pattern of spots on his side – each leopard has a unique pattern. It turned out that this individual had been fitted with a radio-collar back in 1994, more than eight years earlier! The scientists who put the radio-collar on this leopard had named him "Leopold" and estimated his age at that time at 3-5 years. The last time Leopold appeared on a camera-trap photo was in 2004. This means that Leopold reached an age of at least 13 years – as old as Methuselah for a leopard in the wild. This indicates that clever and experienced leopards are not killed easily by poachers, and that inbreeding may not affect the lifespan of Amur leopards.