In plains and mountain zebras, foals are cared for mostly by their mothers, but if threatened by pack-hunting hyenas and dogs, the entire group works together to protect all the young. The group forms a protective front with the foals in the centre, and the stallion will rush at predators that come too close. In Grévy's zebras, mothers may gather into small groups and leave their young in "kindergartens" guarded by a territorial male while searching for water. A stallion may look after a foal in his territory to ensure that the mother stays, though it may not be his. By contrast, plains zebra stallions are generally intolerant of foals that are not theirs and may practice infanticide and feticide via violence to the pregnant mare.