They chiefly eat plant matter. Ostriches sometimes lie on the ground with neck outstretched when enemies are near. This may have given rise to the legend that the bird buries its head in the sand. Actually it is attempting to escape detection or view the enemy against a lighter horizon. Among the three species is Rhea americana, called the common rhea.
Rheas are brownish instead of black like the ostrich and have three toes instead of two.
They live on plants and, like ostriches, move in groups along with other grazing animals. In Brazil, rheas thrive on the open plains where cattle are raised. Annually, gauchos trap rheas in nets, wrestle them one by one to the ground, and take their tail feathers, which are made into dusters. The others were exterminated by European settlers in mainland Australia and Tasmania. Emus lack the graceful plumage of the ostrich .