François’ langur, also known as Francois’ leaf monkey, Tonkin leaf monkey, or white side-burned black langur is a species of lutung. The species is distributed from Southwestern China to northeastern Vietnam. It is a medium sized primate with black silky hair. It has very distinct white sideburns that grow down from its ears to the corners of its cheeks. A morphological specialization of François’ langur is its complex stomach, made up of four separate chambers. This is a necessary adaptation for the digestion of its folivorous diet.
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