By the Cretaceous another oddity of theropod evolution has become obvious. None of them could crush and eat bones the way hyenas do. Walking dinosaur costume Theropods could chew on bones a little, but even stout toothed tyrannosaurs were not bone crushers in the class of hyenas. Hyenas consume whole carcasses, bones and all, with their great jaws and teeth. One would like to imagine theropods with super strongly built and powerfully muscled skulls, the backs of their jaws lined with great, flat bone-cracking teeth. These would have been more efficient at consuming dinosaur carcasses than the theropods we know, but none have shown up in the fossil record. By the Cretaceous crocodilians of essentially modern form were the theropods main competitors. Yet crocodilians appear to be less abundant in most Mesozoic deposits than they are later in the mammal-dominated Cenozoic. Not only that, but they tended to be small-bodied: few specimens were as big as American alligators or Nile crocodiles. It is possible that theropods were eating the crocs. Dinosaur costume Even today, big cats once in a while kill a fairly large crocodilian. A t5rrannosaur could have swallowed one whole, and gone into the water after them. Constant attacks could have suppressed croc populations, and favored the smaller, harder to catch species.
There were gigantic crocodilians called phobosuchids in the Late Cretaceous, which reached forty to fifty feet in length. But they too were uncommon. Animatronic dinosaur While dozens of good tyrannosaur skulls are known from North America, not a single, fully complete phobosuchid skull has been found. Undoubtedly, tyrannosaurs ate juvenile phobosuchids, and on shore even the adult phobosuchids were not safe. On the other hand, when in the water, the slow-breathing ectothermic croc could drown the hieh metabolic theropod by grabbing its foot and dragging it under. Even so, the giant crocs were too rare to ever constitute a serious threat to theropods-in fact, they are missing entirely north of Montana, perhaps because the winters there were too cold for them.