Orangutan Orphan, Borneo

Photograph by Mattias Klum

Clinging to the hand of a human protector, six-year-old Mugi is one of some 500 orphans cared for at the Nyaru Menteng Orangutan Rescue Center in Indonesian Borneo. The island's orangutans are endangered: The population has fallen by more than 50 percent in the past 50 years.