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:
“Science is a system of statements based on direct experience, and controlled by experimental verification. Verification in science is not, however, of single statements but of the entire system or a sub-system of such statements.”
—Rudolf Carnap (1891–1970)