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:
“The system was breaking down. The one who had wandered alone past so many happenings and events began to feel, backing up along the primal vein that led to his center, the beginning of hiccup that would, if left to gather, explode the center to the extremities of life, the suburbs through which one makes one’s way to where the country is.”
—John Ashbery (b. 1927)