Although gray wolves usually travel in packs, there are cases of wolves traveling alone or in pairs: This can happen for different reasons, and they may simply haven't been able to start their own pack yet. Lone wolves can be even more successful at hunting large prey than noisier packs. When food is scarce, gray wolves can eat fruit or plants. In fact, they often eat berries, melons, apples and pears to supplement their diet; gray wolves can eat black nightshade, which can be toxic to humans.