Animal - photo wallpapers; Megawallpapers.org: collection contain many wallpapers. Animals are a major group of organisms, classified as the kingdom Animalia. These are generally multicellular, capable of locomotion and responding to their environment, and feed by consuming other organisms. Their body plan becomes fixed as they develop, usually early on in their development as embryos, unless they undergo a process of metamorphosis. Humans are animals, though colloquially the term is often taken to exclude them. The word comes from the Latin word animal (plural animalia) and ultimately from anima, meaning vital breath. With a few exceptions, most notably the sponges, animals have differentiated tissues, including a nervous system and muscles, and an internal digestive chamber. Groups with this organization may be called metazoan, though that word is also used for the animals in general.