Alternatively, they may have been mainly scavengers, omnivores or even herbivores. The large beak of "Gastornis" would have been suited for crushing seeds and tearing off vegetation. But it seems too strong for a purely vegetarian diet. Regardless of what these birds ate, the beak may have been used also for social display – its presence in all known fossils argues against a sexual display role. These contradicting hypotheses, which can't be separated by the evidence, make the paleobiology of "Gastornis" unclear.