Quetzalcoatlus

Fantasy Fact: Prehistoric dragons weighed over a ton and had a wingspan of more than 35 feet.

Scientific Inspiration: Many Cretaceous animals were larger than their closest modern equivalents. The largest flying animal today is the Andean condor. It weighs 20-30 pounds and has a wingspan of about 10 feet. In the late Cretaceous, the largest flying animal we know of was the giant pterosaur, Quetzalcoatlus. It had a wingspan of over 40 feet. How could larger animals get airborne then, rather than now?

One possible explanation comes from a study of tiny bubbles of air trapped in the resin that dripped from pine trees 80,000,000 years ago. Analysis of this Cretaceous air shows that it was composed of approximately 30 percent oxygen, compared with the 20 percent in today's atmosphere. Higher oxygen concentration means that muscles can potentially generate more power. The giant Quetzalcoatlus may have grown larger in response to the oxygen-rich Cretaceous atmosphere.