British scientists say their new technique to accurately measure the weight and size of dinosaurs shows they were not as heavy as previously thought.

University of Manchester biologists used lasers to determine the minimum amount of skin required to wrap around the skeletons of modern-day mammals, then applied the technique to a giant Brachiosaur skeleton in a Berlin museum.

While previous estimates of this Brachiosaur's weight have been as high as 80 tons, the Manchester researchers' calculations, published in the journal Biology Letters, reduced that figure to just 23 tons -- still about twice the weight of the largest recorded elephant.

The biologists said the new technique would apply to all dinosaur weight measurements.

"One of the most important things palaeobiologists need to know about fossilized animals is how much they weighed," Manchester researcher Bill Sellers said. "We laser scanned various large mammal skeletons, including polar bear, giraffe and elephant, and calculated the minimum wrapping volume of the main skeletal sections.

"We showed that the actual volume is reliably 21 percent more than this value, so we then laser scanned the Berlin Brachiosaur, Giraffatitan brancai, calculating the skin and bone wrapping volume and added 21 percent.

"We found that the giant herbivore weighed 23 tons, supporting the view that these animals were much lighter than traditionally thought." (UPI)