British scientists have discovered that dinosaurs were a lot lighter than we used to think. A team at the University of Manchester did it using laser scanners on animal skeletons. They calculated how much animals would weigh if they were just skeletons wrapped in skin but without the normal fat and muscles. For almost any mammal, the full weight was about 20 per cent more than the weight with just skin and bones. Then they scanned a giant Brachiosaur skeleton, calculated the skin and bones weight, and added the missing 20 per cent. It turned out to be about 23 tonnes — only around a quarter of some previous estimates.