Brachyteles arachnoides, commonly known as the southern muriqui, is a species of primate found in the Atlantic Forest of Brazil. It is notable for its long limbs and prehensile tail, which help it navigate the treetops. This species is classified as critically endangered due to habitat loss and hunting. Southern muriquis are social animals, living in groups that can include both males and females. They primarily feed on leaves, fruits, and flowers, playing a vital role in their ecosystem by aiding in seed dispersal. Conservation efforts are underway to protect their remaining habitats and ensure their survival.