Written by: Dr. Jacquie Jacob, University of Kentucky
A ratite is a bird that does not have a keel. Ratites do not fly, so they do not need the strong breast muscles typical in birds that have a keel (such as chickens, turkeys, and ducks). Figures 1 and 2 illustrate the difference between a ratite and a bird with a keel. Ratites include ostriches, emus, and rheas. Ostriches have two toes on each foot, with one toe having a long nail that the ostrich uses to lash out at predators. Emus and rheas have three toes on each foot, and neither the emu nor the rhea has hind toes. See Figures 3 and 4 for comparisons of the external characteristics of emus and rheas.
Fig. 1. Ostrich skeleton (left), close-up of the breast area (right). Source: Jacquie Jacob, University of Kentucky.
Fig. 2. Chicken skeleton showing the keel bone. Source: Public domain.
Fig. 3. Comparison of a rhea and an emu. Source: Jacquie Jacob, University of Kentucky.
Fig. 4. Comparison of the head of a rhea and the head of an emu. Source: Jacquie Jacob, University of Kentucky.