Conservation: Saving the Man of the Forest

Youngsters roll on the ground, tussling, teasing each other and gleefully aping their elders. They climb the tropical trees with abandon and plunge happily into cooling water—holding their noses when they dunk. Despite the similarities, the equatorial playground, at the edge of a 12,000-acre forest preserve on Borneo is no boys' camp. It is the Malaysian state of Sabah's experimental center for the rehabilitation of orangutans.

The orangutan—Malay for "man of the forest"—is badly in need of a helping hand. Once these big red-haired primates (an adult male stands about 5 ft. tall, weighs 150 lbs.) inhabited the jungles of...