Hesperornis was clearly an actively swimming bird that probably chased and caught fish. Although unrelated to today's loons (loon) (order Gaviiformes), many of Hesperornis's skeletal features resembled those of loons, and, like loons, Hesperornis is thought to have been a good diver. The wings were small and useless for flight, and the wing bones were splintlike. The breastbone lacked the prominent keel that serves as an anchor for powering flight muscles. The legs, however, were powerfully developed and clearly adapted for rapid diving and swimming through water. The neck was slender and the head long and tapered; both were probably capable of rapid side-to-side movement.