Rhinopithecus avunculus, commonly known as the grey snub-nosed monkey, is a primate species found in the mountainous forests of Vietnam. This species is characterized by its distinctive flat nose and long tail, which help it navigate through the trees. They primarily feed on leaves, fruits, and flowers, making them folivorous. These monkeys are social animals, living in groups that can range from a few individuals to over a hundred. Rhinopithecus avunculus is currently classified as endangered due to habitat loss and hunting, highlighting the need for conservation efforts to protect their natural environment.