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 Some dinosaurs¹ were really huge, and now we may have a better way to estimate just how heavy these giants were. Researchers have developed a method to weigh dinosaurs based on laser scans of their skeletons. The study is in the journal Biology Letters. Looking at a bare human skeleton, how would you guess wether its owner was chubby² or svelte³? If you calculated how much space the fully-fleshed body occupied, you could multiply that volumn by tissue density⁴ to find the weight. Researchers laser-scanned 14 modern mammal skeletons to create digital models of each body. These 3-D models were unrealistically scrawny, with skin streched tight ove the bones. But their undersized volumns were consistent, measuring is 21% less than the actual animals. Based on the same information, researchers scanned Giraffatitan bones, added 21% to the digital model's volumn, and then calculated the dinosaur's weight---about 51,000 pounds. The technique could become the preferred way to estimate mass based on skeletons, improving our understanding of how extinct species lived and moved, and helping⁵ paleontologists make earth-shaking discoveries.