What is an animal? It's a simple enough question, but the answer is complex and requires an understanding of some rather hefty scientific concepts and terms. Here we'll explore the basic characteristics that make an organism an animal and attempt to decipher the scientific jargon that surrounds these concepts.
It's easy to say, for instance, that a giraffe, a whale, or a dog is an animal. But when it comes down to making a list of animal characteristics—identifying specific traits shared by all animals—it gets complicated.
The list that follows describes characteristics shared by all animals, from snails and zebras to mongooses and sea stars. These characteristics help us to declare that, for instance, corals are animals, not plants. They help us trace the evolution of animals and build a framework for placing animals into subcategories that are more familiar to us such as birds, mammals, reptiles or amphibians.