Among the largest flying birds, Swans are the largest members of the duck family. Generally living in temperate environments, swans rarely live in the tropics. Species are known in the Northern Hemisphere, New Zealand and Australia, and a species in South America. They are not known in tropical Asia, Central America, northern South America, and all of Africa. They feed both in the water and on land. Their diet includes very few aquatic animals and generally swans are herbivorous.