English: Hesperornis is a genus of cormorant-like bird that lived throughout the Campanian age, and possibly even up to the early Maastrichtian age, of the Late Cretaceous period. It was a large bird, reaching up to 1.8 m in length. It had virtually no wings, and swam with its powerful hind legs. It is unknown whether Hesperornis had lobed toes similar to modern-day grebes, or webbed toes as seen in most aquatic birds. Like many other Mesozoic birds, Hesperornis had teeth as well as a beak. The teeth were present along nearly the entire lower jaw and the back of the upper jaw. Studies of the bone surface show that at least the tips of the jaws supported a hard, keratinous beak similar to that found in modern birds.