Size is an important aspect of dinosaur paleontology, of interest to both the
general public and professional scientists. Dinosaurs show some of the most
extreme variations in size of any land animal group, ranging from tiny
hummingbirds, which can weigh as little as two grams, to the extinct
titanosaurs, which could weigh as much as 50–100 t (55–110 short tons).
The latest evidence suggests that dinosaurs' average size varied through the
Triassic, early Jurassic, late Jurassic and Cretaceous periods, and dinosaurs
probably only became widespread during the early or mid Jurassic.