The biggest animals ever to have walked on Earth were the long-necked, long-tailed dinosaurs known as sauropods, and the most famous of these giants was likely Brontosaurus, the "thunder lizard." ...
Would it counteract the planet’s gravity more so that, at the time of the dinosaurs, a Brontosaurus would weigh a little less that it would if it existed now? It’s an intriguing question.