Scientists at the Colorado University in the US claimed to have found that the original statistical model, used to calculate dinosaur mass, was flawed.
The model showed dinosaurs as oversized animals due to the imperfection of the evaluating techniques, they said.
"Paleontologists have for 25 years used a published statistical model to estimate body weight of giant dinosaurs and other extraordinarily large animals in extinct lineages," said Gary Packard of the university.
"By re-examining data in the original reference
For example, the estimate for the mass of Apatosaurus louisae, one of the largest dinosaurs, was 38 tonnes and may plummet to 18 tonnes after the error in the model is rectified, Packard said.
The study was published in the June 21 issue of the Zoological Society of London's Journal of Zoology.
The revelation is of significance in view of the numerous theories about the biology of dinosaurs, ranging from their energy metabolism and requirement of food besides their modes of locomotion.