Dinosaur size

Size has been one of the most interesting aspects of dinosaur science to the general public and to scientists. Dinosaurs show some of the most extreme variations in size of any land animal group, ranging from the tiny hummingbirds, which can weigh as little as three grams, to the extinct titanosaurs, which could weigh as much as 70 tonnes.

Scientists will probably never be certain of the largest and smallest dinosaurs to have ever existed. This is because only a tiny percentage of animals ever fossilize, and most of these remain buried in the earth. Few of the specimens that are recovered are complete skeletons, and impressions of skin and other soft tissues are rare. Rebuilding a complete skeleton by comparing the size and morphology of bones to those of similar, better-known species is an inexact art, and reconstructing the muscles and other organs of the living animal is, at best, a process of educated guesswork. Weight estimates for dinosaurs are much more variable than length estimates, because estimating length for extinct animals is much more easily done from a skeleton than estimating weight. Estimating weight is most easily done with the laser scan skeleton technique that puts a "virtual" skin over it, but even this is only an estimate.