Like other apes, orangutans don't have a tail. Orangutans spend most of their life in the trees, swinging confidently from branch to branch. Their long fingers and toes can easily grasp branches and vines.

Why do orangutans have flaps?

Male-male competition for access to sexually receptive females is a major factor in orangutan adaptation. Flanged adult males use their pendulous laryngeal sacs as a resonating chamber for the “long call,” parts of which sound like a loud roar. Sometimes the sound of a long call can carry for almost a mile.

Is an orangutan a monkey?

There are only a handful of ape species, while there are hundreds of species of monkeys. If the primate you're trying to place is not a human, gibbon, chimpanzee, bonobo, orangutan, or gorilla (or a lemur, loris, or tarsier), then it's a monkey.