Current evidence suggests that dinosaur average size varied through the Triassic, Early Jurassic, Late Jurassic and Cretaceous. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the category. The mode of Mesozoic dinosaur body masses is between . This contrasts sharply with the average size of Cenozoic mammals, estimated by the National Museum of Natural History as about .