 <unk> what Iguanodon ate with its well @-@ developed jaws is not known . The size of the larger species , such as I. bernissartensis , would have allowed them access to food from ground level to tree foliage at 4 – 5 metres ( 13 – 16 ft ) high . A diet of <unk> , <unk> , and conifers was suggested by David Norman , although iguanodonts in general have been tied to the advance of <unk> plants in the Cretaceous due to the dinosaurs ' inferred low browsing habits . <unk> growth , according to this hypothesis , would have been encouraged by <unk> feeding because <unk> would be removed , allowing more space for the weed @-@ like early angiosperms to grow . The evidence is not conclusive , though . Whatever its exact diet , due to its size and abundance , Iguanodon is regarded as a dominant medium to large herbivore for its ecological communities . In England , this included the small predator <unk> , larger predators <unk> , <unk> , and <unk> , low @-@ feeding herbivores Hypsilophodon and <unk> , fellow " <unk> " Mantellisaurus , the armoured herbivore <unk> , and <unk> like <unk> . 
