Tyrannosaurus rex dinosaur, artwork. . This large bipedal dinosaur is one of the largest ever terrestrial predators. From its large olfactory lobes, it is thought to have possessed a very well developed sense of smell. To find the amount of food it needed to sustain itself, it probably relied on a combination of hunting and scavenging. Its fossils are found in North America, and date to the Cretaceous. Here, it is scavenging on a dead mosasaur that has washed up on the shores of the Western Interior Seaway.