Orangutan (Pongo pygmaeus)
As apes, orangutans are among our closest mammal relatives. They are the only truly arboreal apes—and the largest animals in the canopy. Orangutans are so adapted to life in the trees that they cannot survive outside their rainforest habitat. Once found throughout much of Southeast Asia, they now live only in the lowland and hilly tropical rain forests of Borneo and Sumatra. Here, logging and forest fires have edged them toward extinction.