Greater Rhea

The largest bird in the Americas, the greater rhea is a flightless runner that steers with outstretched wings and can outrun a horse across open pampas. Its long neck and small head give it a browsing view of the grass, and it swallows pebbles to grind up tough vegetation.

In a role reversal rare among birds, the male alone incubates the eggs — laid by several females in one nest — and then raises the chicks by himself, defending them fiercely for months.