The bigger the dino, the warmer its blood: researchers

Large dinosaurs are more like us than you think, according to U.S. scientists who've found that the "terrible lizards" aren't as cold-blooded as they once thought.

Researchers from the University of Florida found that the prehistoric animals were likely able to regulate their body heat like mammals, suggesting that the blood of some dinosaurs was warmer than most reptiles.

The scientists created an equation to measure the body temperature of dinosaurs according to their body weight.

The results showed that the larger the dinosaur, the longer it took for heat to leave its body. This is known as inertial homeothermy, when temperature is maintained by slow cooling. Cold-blooded reptiles, such as lizards and snakes, depend on their outer surroundings to keep warm.

Researchers used measurements of annual growth rings in the bones of eight different dinosaur species to estimate their growth rates. With the measurements, the scientists were able to use the equation to calculate body temperature.

They found smaller dinosaurs had a body temperature of 25 degrees Celsius. (The average temperature inside warm-blooded humans is 37 C.)

According to the researchers, the sauropod Apatosaurus, which weighed close to 36 tonnes, had a body temperature of 40 C.

Photography: Harper Collins

Source: Discovery Channel Reports, July 11 edition