Asia's leaf monkeys take their name from the lush jungle foliage that makes up the bulk of their diets. All are equipped with a large, chambered stomach, like that of a cow, which allows them to break down and digest their fibrous fare.
Endemic to the jungles of Indonesian and Malaysian Borneo, red leaf monkeys are named for their shaggy auburn coat. They are also known as maroon langurs and maroon leaf monkeys.
These charismatic Old World primates live in bands of 2 to 13 individuals, led by a dominant male, and spend nearly all their time in the trees. They have broad, dark-colored faces with wide, expressive eyes. They average between 13 and 14 pounds.
Beyond leaves, red leaf monkeys also consume large amounts of seeds and flowers. They also eat fruit but avoid sweet, ripe fruit because the sugars disrupt the delicate balance of their complex stomachs.
Red leaf monkeys are highly territorial and will challenge any intruders within their home range. Males emit a loud call to demarcate their territory and warn rivals away.
This species is under some pressure from hunting and habitat loss, but is quite common throughout its range. Nevertheless, they are protected by law throughout Malaysian Borneo.