Downsizing a giant

Collaboration between four UK universities has found that the world’s largest dinosaur isn’t quite as big as previously thought.

Credit: Biology Papers.

Faculty scientists from The University of Manchester teamed up with scientists from the University of Liverpool, Liverpool John Moores and Imperial College London to help create a computer reconstruction of a dinosaur called Dreadnoughtus. They used this model to help predict the overall mass of the now extinct animal.

Dreadnoughtus, a herbivore with a long neck and tail, was thought to weigh around 60 tonnes but this new model puts the dinosaur’s weight at a more moderate 38 tonnes.

The original estimate of 60 tonnes came from a calculation that was based on the circumference of one of the dinosaur’s fossilised remains and then comparing that to animals that are alive today and their weights. However, the team used a different approach. They fitted simple shapes to a digital model of the Dreadnoughtus’ skeleton and calculated the volume. This volume was then converted into a body mass, using data collected from similar modern animals.

Dr Charlotte Brassey who headed up the Faculty’s involvement explains the results:

“The model we have used here shows that for Dreadnoughtus to have reached the originally estimated size it would have either needed a much higher body density, or much more soft tissue than you find in living four-legged animals.”

She adds:

“While Dreadnoughtus was clearly a huge animal, we don’t think it would have grown to quite as big as the 60 tons originally claimed.  Estimating the size of an animal from its bones necessarily means you have to theorise, but we think our figure fits much better with what we currently understand about the size and shape of modern land animals.”

The paper, ‘Downsizing a giant: re-evaluating Dreadnoughtus body mass’, has been published in the Royal Society journal Biology Letters.