The largest known hadrosaurid is Shantungosaurus giganteus, from China, shown here in red with a selection of other unacceptably large hadrosaurs:

The largest specimens we know of would have been about 16 metres (54 feet) long and weighed 16 tonnes, its skull was as long as the average person is tall, and that’s just the largest we know. These things were well and truly sauropod-scale.

(Reconstruction by Jack Wood @thewoodparable )

Ranking in just below Shantungosaurus is still-stupidly-huge Magnapaulia laticaudus, the largest known lambeosaurine:

(reconstruction by Gabriel Ugueto)

Magnapaulia’s length has been estimated from 12 to 15 metres. This is just … not okay in any way, shape, or form. Who said this was allowed?

In general, hadrosaurs were probably a lot bigger than most people perceive them as, probably due to their being consistently typecast as the peaceful, helpless victims of theropods. Many of the later hadrosaurs reached 12 metres or longer, and were the size of a small elephant.

There’s an Edmontosaurus Skeleton at the Denver Museum of nature and sciene which has always made me glad I’m living Right Now And Not Back Then because it’s roughly the size of a Semi Truck and has the NERVE to look light and graceful enough to be able to Actually Gallop/run my ass down.

An Average Human doesn’t even come up to it’s elbow.