The Southern muriqui (Brachyteles arachnoides), the largest primate in the Americas, is our primary interest. Observers are drawn to this species for its impressive size, striking beauty, and its sociable and gregarious nature. Regrettably, it is classified as critically endangered on the IUCN Red List.

In São Francisco Xavier (SFX), they are commonly spotted in groups of 2 to 30, comprising females, males, and young. Observing them as they feed in the canopy and exhibit their innate behaviors is a remarkable experience.