The Rhea is a large, flightless bird from the forests of South America. This ratite is the largest bird in the Americas. The rhea is a fast runner; when it runs, its neck is almost horizontal to the ground. Rheas are polygamous, with males courting between two and twelve females. After mating, the male builds a nest, in which each female lays her eggs. The female rhea will lay 12-30 yellow-cream eggs in a clutch. The male incubates from 10 to 60 eggs for six weeks; the chicks will hatch within 36 hours of each other. The females, meanwhile, may move on and mate with other males. The male will utilize a decoy system and place some eggs outside the nest and sacrifice these to predators, so that they won't attempt to get inside the nest. The male may also utilize another subordinate male to incubate his eggs, while he finds another harem to start a second nest. While caring for the young, the males will charge at anyone - including humans and female rheas - who approaches the chicks. They are omnivorous, preferring broad-leafed plants, but also eating seeds, roots, fruits, insects, and small vertebrates. Rheas have only three toes. This is an adaptation which allows them to run faster than if they had four. They can grow up to 5 feet tall. There are no tail feathers and the wings are large but useless. Rheas are mature at two years of age.