the ground, but nests and roosts in trees. This species is gregarious, occurring in groupings of up to a dozen birds, though occasionally birds can be seen alone. Its diet consists mainly of fruits, figs and arthropods. Small vertebrates may supplement the diet on occasion, including small mammals (such as rodents). Unlike other cracids, such as guans, they feed largely on fallen fruit rather than pluck fruit directly from the trees. In Tamaulipas, it feeds largely on the fruit Spondias mombin. Elsewhere, it may prefer the red berries of Chione trees. The male great curassow may build the nest and attract a female's attention to it, though in other cases both members of a pair will build the nest structure. Two eggs are typically laid in a relatively small nest (usually made largely of leaves), each egg measuring and weighing . The young curassow weighs upon hatching; as a half-year-old immature fledgling; and by a year of age, when fully fledged and independent of parental care, will be about three-quarters of their adult weight at . This species has been noted for its rather aggressive temperament, which has been regularly directed at humans when the birds are held in captivity. Undoubtedly, they have this inclination in order to repel natural predators, from both themselves and their offspring. Known natural predators of this species have included ocelots and ornate hawk-eagles, though chicks and eggs likely have a broader range of predators. When a potential predator is near their offspring, curassows have been noted to engage in a distraction display, feigning injury. When attacking humans, the curassows leap in fluttering flight and scratch about the head, targeting the eyes. Their lifespan in captivity has reached at least 24 years. Paleontology The great curassow is the most northerly Crax species. It is part of a clade that inhabited the north of South America since about 9 mya (Tortonian, Late Miocene). As the Colombian Andes were uplifted around 6 mya, this species' ancestors were cut off from the population to their southeast. The latter would in time evolve into the blue-billed curassow. The ancestral great curassows then spread along the Pacific side of the Andes, and into Central America during the Pliocene and Pleistocene as part of the Great American Interchange. Status Due to ongoing habitat loss and overhunting in some areas, the great curassow is evaluated as Vulnerable on the IUCN Red List