Biologists long assumed that one-way air flow was a special adaptation in birds driven by the intense energy demands of flight. But now scientists have shown that bird-like breathing also developed in green iguanas – reptiles not known for high-capacity aerobic fitness. The finding bolsters the case that unidirectional bird-like flow evolved long before the first birds. Read Complete Article ... Use this thread to discuss the article above. What are your thoughts about Why lizards have bird breath: Iguanas evolved one-way lungs surprisingly like those of birds?