It was thought that birds gained an energy advantage by escaping cold winters, but new research has quashed that assumption.

The metabolism of gulls and parakeets is measured during ascending, descending and level flight in the wind tunnel. The results show how flying birds can husband their "fuel" By Vance A. Tucker ...

For their size, some birds have remarkably long lifespans. They live at least three times as long as mammals of the same size, despite shared qualities such as a high body temperature, high metabolism ...

All regularly shed the outer layer of their skin. Their metabolism depends on the temperature of their environment. Unlike birds and mammals, reptiles do not maintain a constant internal body ...