The ostrich originated in Africa and has been commercially raised since 1850 for feathers, meat, and hide products. The emu originated in Australia and has been raised for meat, oil, and leather. The South American rhea has been produced primarily for feathers.
Ostriches (Struthio camelus) are the largest members of the ratite group. Mature ostriches may stand 2.4–2.8 m tall and weigh up to 160 kg although most are 65–130 kg. Males are black and white, females are brown.
Emus (Dromaius novaehollandiae) are second only to ostriches in size, measuring up to 2 m tall and weighing 18–48 kg. Both males and females have plumage that is brown to gray-brown; feather shafts and tips are black. Emus are flightless but travel at a quick trot and can sprint at speeds up to 51 km/hr.
Rheas can reach 1.7 m in height and 40 kg in weight. They are native to South America and are divided into 2 species: the Greater Rheas (Rhea americana) include 5 subspecies, and the Lesser Rheas (Rhea pennata) include 3 subspecies. Like emus, their feathers are brown to gray-brown.
Last full review/revision July 2011 by Karen Hicks-Alldredge, DVM