Did T.rex have any predators?

T. rex was probably the top carnivore of the Late Cretaceous Period and would have had few if any natural enemies. The only threat to T. rex would have come in the form of other tyrannosaurs which lived at the time: Daspletosaurous, Albertosaurus, Nanotyrannus; these may well have preyed upon young T. rex but the adults would have been left well alone!