There are fewer than 2,000 wild orangutans left in the West Kalimantan province, Indonesia.

The couple started the project to study the ecology and behavior of wild orangutans.

The critics question if the behavior of the apes mirrors that of a wild orangutan or not.

If you want company and still see wild orangutans, going to the Kinabatangan River is probably your best bet, though it has its drawbacks, too.

Participants help with the rehabilitation of formerly captive orangutans and spend several days tracking wild orangutans through the jungle.

People have been studying wild orangutans for 30 years," he said, "but they've been looking at behavior.

The Mawas area is home to one of the last tracts of forest supporting wild orangutans.

Due to the destructive activities of humans, the population of wild orangutans may have diminished in the past decade by as much as 50%.

Some wild orangutans have learned to get water from a hole by dipping a branch into it and then licking the leaves.

Although similar swamps can be found in Borneo, wild Bornean orangutans have not been seen using these types of tools.