Circulatory System
Birds have a four-chambered heart, in common with humans, most mammals, and some reptiles (namely the crocodilia). This adaptation allows for an efficient nutrient and oxygen transport throughout the body, providing birds with energy to fly and maintain high levels of activity. A Ruby-throated Hummingbird's heart beats up to 1200 times per minute (about 20 beats per second).
Read more about this topic: Bird Topography
Famous quotes containing the word system:
“I need not say what match I would touch, what system endeavor to blow up; but as I love my life, I would side with the light, and let the dark earth roll from under me, calling my mother and my brother to follow.”
—Henry David Thoreau (1817–1862)