external anatomy of ratites

written by: dr. jacquie jacob, university of kentucky

a ratite is a bird that does not have a keel (the breastbone of a bird). 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.

ostrich skeleton
figure 1. ostrich skeleton (left) and close up of the breast area (right): source: dr. jacquie jacob, university of kentucky.
chicken skeleton showing the keel bone
figure 3. chicken skeleton showing the keel bone (image by arogant from shutterstock.com)
photos of emu and rhea
figure 3. comparison of rhea and emu. source: dr. jacquie jacob, university of kentucky
emu and rhea heads
figure 4. comparison of the head of a rhea and the head of an emu. source: dr. jacquie jacob, university of kentucky

back to the anatomy of menu