The Bald Eagle

The Bald Eagle is the preeminent symbol of the United States of America. The reasons for this are somewhat speculative or subjective but usually pertain directly to the actual anatomy of the bird and its association with certain concepts. The eagle has a graceful aerodynamic beauty that is inspirational. His eyesight is four times sharper than ours. He soars, for real, and in our minds. Yet he is a creature that is also aggressive and ruthless when hunting or defending his territory. When he dives, he does so at a speed approaching 150 mph. On the Great Seal, in one talon, he holds a bundle of arrows, and in the other, an olive branch, signifying the bipolar "war and peace" nature of the Union. In understanding the structure that animates the eagle, the artist is better able to depict the psychophysical components that continue to make him a transcendent part of the American's imagination.

Most species of eagles are found in the Eastern Hemisphere. The Bald Eagle and the Golden Eagle are the only two found in North America with the Bald Eagle being unique to the continent. Bald Eagles, aka Haliaeetus leucocephali ("sea eagle with a white head"), are members of the Falconiformes Order and the Accipitridae Family. They are often referred to as raptors because they are birds that hunt their prey with large talons, a predominant feature of their anatomical structure. Raptors also have such large eyes that they are unable to rotate them in the socket. The limitation is compensated for by their flexible vertebral column which contains fourteen vertebrae. The eye size and its placement on the side of the skull enable the eagle to achieve a "dual focus" on an object in front as well as to the right or left at the same time.

Another interesting feature is that their respiratory air sacs are not confined to the lungs but exist throughout the body and within their hollow bones. This extensive breathing system enables them to take in the enormous amounts of oxygen which are required to fuel the extensive burden on the muscles when flying. This also acts as a cooling system. The bald eagle has a wingspan that can reach up to 7 ft. It weighs anywhere from 8-14 pounds. The wings are flexed by two powerful pectoral muscles that meet together on an enormous breastbone or sternum.