To survive eagles depend on their ability to fly. Their bodies are designed for flight. To be a good flyer, an eagle's body has to be both strong and light weight. Eagles have several adaptations that make their bodies light enough to get off the ground, but powerful enough to catch and kill their prey.

When an eagle flaps it's wings, most of the lift that powers the eagle into the air comes from the downward stroke. Because the downward stroke is so important, the muscles responsible for this motion are huge! The flight muscles of an eagle can account for half of its total body weight.

Like all birds, eagles have hollow bones. Whoa! What advantage would there be to having hollow bones? Don't they break easily?

It takes a lot of energy to fly. The more a bird weighs, the more energy it takes to fly. Eagles have a lightweight frame that gives them maximum strength with the least possible amount of weight. In fact, the weight of an eagle's skeleton is only half a pound!

Math problem: If a Bald Eagle, Rainbow, weighs 8 pounds with a half pound being the total weight of her skeleton, what percentage of Rainbow's total body weight is bone? Answer: 6.25% (Show the work.)