Hadrosaurus was a 5-ton (4.5-metric-ton), late Cretaceous animal and was the first dinosaur to be discovered and named in North America-in 1858 from fossils found in New Jersey. Corythosaurus was a 36 ft-long (11 m-long), 4 ton (3.6 metric ton), Late Cretaceous herbivore that had a large, hollow, helmet-like crest on the top of its head. Parasaurolophus of the late Cretaceous was similar in size, but it had a curved, hollow crest that swept back as far as 10 ft (3 m) from the back of the head. It has been suggested that this exaggerated helmet may have worked like a snorkel when this animal was feeding underwater on aquatic plants; however, more likely uses of the sweptback helmet were in species recognition and resonating the loud sounds made by these hadrosaurs. Edmontosaurus was a large, non-helmeted hadrosaur that lived in the Great Plains during the late Cretaceous and was as long as 40 ft (13 m) and weighed 3 tons (2.7 metric tons). Anatosaurus was a 3 ton (2.7 metric-ton) hadrosaur that lived as recently as 66 million years ago and was among the last of the dinosaurs to become extinct. The hadrosaurs probably were a favorite prey for some of the large theropods, such as Tyrannosaurus rex.
The 3.5 ton figure is much closer to the range of published Hadrosaur values.
How is it that an animal that is arguably twice the size of a modern male African elephant weighs the same as an average female African elephant?
Something is wrong here. I grant that the tail and head taper toward the extremities, but the main body mass, although much larger, appears in the National Geographic pictures to be proportionate to the elephant's.
According to the square-cube law if the size of an animal is increased, the skin area will be increased by a factor of the square of the size multiplier and the volume will be increased by a factor of the cube of the size multiplier.
If we start with a young hadrosaur, at the same size as a modern elephant, 6,000 lbs, and it doubles proportionately in size, the volume (and equivalent probably the mass) would be eight times (23 larger! That's 8 X ~6,000 lbs = ~48,000 lbs.
Or are the saying an animal with that massive neck and equally massive tail has a really skinny body or is completely hollow inside?