"The method we present is a big advance because it allows a direct measurement of the body temperature of extinct species, free from the assumptions required with other approaches," Eagle said.
Hulbert said previous research to measure body temperatures of extinct species by comparing concentrations of oxygen-16 and oxygen-18 involved making several assumptions about climate during mineral formation including average humidity of a region, the degree of seasonality and distance from nearest ocean.
The study authors concede there are limitations to the clumped isotope analysis method for studying the evolution of thermoregulation. The results are not a lifelong record and only provide a snapshot of temperature of that animal's body part at the time of formation. Hulbert also said if the tooth enamel has been significantly altered or chemically changed over geologic time, the method will not work.
Eagle said further testing of different-sized dinosaurs and other extinct vertebrates will provide more evidence about whether they were warm- or cold-blooded.
"Temperatures in the range of 26 to 30 degrees Celsius would suggest dinosaurs were similar to alligators and crocodiles," Eagle said. "Temperatures of 36 degrees or higher would be interesting but would not necessarily mean that they were warm-blooded like mammals. It's possible the higher body temperature could be a result of their large body mass, which allows grea
|Contact: Richard Hulbert|
University of Florida