Warning: Undefined array key "visitor_referer_type" in /var/www/vhosts/wordinf.com/core/app/libraries/Core.php on line 98 Mark Norell - When people look of non-avian dinosaur...
When people look of non-avian dinosaur they're thinking of extrapolating a cow up to that size. Mammals are much much denser than birds are, because a lot of the skeletons of sauropods (the big, long-necked ones-Apatosaurus, Brachiosaurus and the like) and theropod dinosaurs are just air. Theropods don't have solid bones like we do; they have hollow bones. Sauropods don't, but they have tremendous air sacs that fill up a lot of their bodies. And thus they weigh way less than a mammal scaled up to that size.