The Mason Spirit

Geoffery Birchard

Dinosaurs have been depicted throughout popular culture as the largest animals to have ever walked on Earth. While they still retain this status, a new study suggests that some dinosaurs may actually have weighed as little as half as much as previously thought.

Geoffrey Birchard, associate professor of environmental science and policy at Mason, was part of a team that uncovered a problem with the statistical model used by some scientists to estimate the mass of dinosaurs. The team conducted a study, Allometric Equations for Predicting Body Mass of Dinosaurs, the findings of which were published in the Journal of Zoology.

“The original equation used by scientists produces fairly accurate results when determining the mass of smaller animals, but when used on larger animals, our research shows that many errors have occurred,” says Birchard. “The new equation shows that dinosaurs are much smaller than we thought, but there is no mistaking that they were indeed huge animals.”

Birchard and his colleagues found the error when they used the equation to determine the weight of living animals, such as a hippopotamus and an elephant, and discovered that the equation greatly overestimated their weight. The researchers have since developed a new equation for calculating dinosaur mass based on bone dimensions.

According to Birchard, this new research changes many of the characteristics scientists had determined about dinosaurs, such as the amount of muscle required to use their bodies and how much they ate and breathed.

—Catherine Ferraro