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:
“A person, seasoned with a just sense of the imperfections of natural reason, will fly to revealed truth with the greatest avidity: while the haughty Dogmatist, persuaded that he can erect a compleat system of Theology by the mere help of philosophy, disdains any further aid, and rejects this adventitious instructor.”
—David Hume (1711–1776)