The largest plant-eating dinosaur was the argentinosaurus. It was not only the largest plant-eating dinosaur, but probably the largest
dinosaur to have ever roamed the Earth.
This dinosaur (which was a sauropod) is believed to have grown to an incredible length of about 40 metres (130 feet). It might have weighed about 80–100 tons. As seen in the left hand side picture, it had a long neck and tail, and a small head.