A herd is a large group of animals and is a form of collective animal behavior. The term is usually applied to mammals, particularly ungulates. Other terms are used for similar phenomena in other types of animal. For example, a large group of birds is usually called a flock (this may also refer to certain mammals as well) and a large group of carnivores is usually called a pack. In addition, special collective nouns may be used for particular taxa: for example a flock of geese, if not in flight… (More on Herd)