Scientists have developed a new laser technique to measure the weight and size of dinosaurs - and found they were much lighter than previously thought.
University of Manchester biologists used lasers to measure the minimum amount of skin required to cover the skeletons of modern-day mammals, including reindeer, polar bears, giraffes and elephants.
And they found that in each case the animals had almost exactly 21 percent more body mass than the bare minimum 'skin and bone'.
Applying this to a giant Brachiosaur skeleton in Berlin’s Museum für Naturkunde produced a much lower weight than previous estimates, which have ranged as high as 80 tonnes. Indeed, the new technique produced a figure of just 23 tonnes.
"Volumetric methods are becoming more common as techniques for estimating the body masses of fossil vertebrates but they are often accused of excessive subjective input when estimating the thickness of missing soft tissue," says the university's Bill Sellers.
"Here, we demonstrate an alternative approach where a minimum convex hull is derived mathematically from the point cloud generated by laser-scanning mounted skeletons. This has the advantage of requiring minimal user intervention and is therefore more objective and far quicker."
The team says the technique should be accurate for all dinosaurs, and means that most were significantly lighter than previously believed.
"Our method provides a much more accurate measure and shows dinosaurs, while still huge, are not as big as previously thought," says Sellers.