A Javan rhinoceros triggers a camera trap in Indonesia's Ujung Kulon National Park in late 2010. The picture was released this week by WWF-Indonesia and Indonesia's National Park Authority.
A motion-activated video camera also recorded "dramatic" footage of four of the rhinos, deemed gravely endangered by the International Union for Conservation for Nature. At fewer than 40 individuals, the Javan rhino may be the rarest mammal on the world, according to WWF.
Though the videos and pictures are "great news," the animals still face serious threats, WWF-US chief scientist Eric Dinerstein noted in a statement.
For instance, an explosion of the nearby Anak Krakatau volcano could easily wipe out all life on the peninsula that the rhinos call home.
"There are no Javan rhinos in confinement," he said. "If we lose the population in the wild, we've lost them all."