Dinosaurs hunted and killed other dinosaurs. A few huge relatives of crocodiles, such as Deinosuchus and Suchomimus, probably hunted dinosaurs. A few of the largest mammals alive at the time, such as Repenomamus, may have hunted dinosaur hatchlings. Scientists consider birds a subdivision of dinosaurs, in which case any animal that hunts birds kills dinosaurs. Of course, prehistoric pathogens would have killed some dinosaurs through disease.