The black-horned capuchin (Sapajus nigritus) is a member of the capuchin family living in the tropical rainforests of Argentina and southeastern Brazil. Diurnal, it eats a varied diet of fruit and seeds as well as frogs, birds, insects, and eggs, and grasps branches with its prehensile, coiled tail. Troops number 5–25 individuals led by an alpha male and form a matrilineal society. Gestation lasts about five months, weaning occurs at around one year, and the species is currently classified as Near Threatened due to habitat loss and hunting.