How Did Dinosaurs Get So Big? Maybe Because They Were Couch Potatoes

Dinosaurs are objects of eternal fascination to we puny humans because of their sheer size. Some, like the long-necked sauropods, are thought to have had eight times the mass of an African elephant, the largest modern land animal. Now a new model from zoologist Brian McNab suggests that the secret of dinosaurs' size was really quite simple: They had plenty to eat, and didn't have to expend much energy in their daily lives. Says McNab: