Most animals are made up of more than one cell, have cells that group into tissue, reproduce sexually, are capable of movement and ingest other organisms to obtain energy. There are exceptions to many of these characteristics, however.
Animals are made up of more than one cell. This characteristic is required to be classified as an animal but is not unique to animals as there are multiple types of organisms that are also multicellular. Most animals have differentiated types of cells that make up various types of tissue, such as nervous tissue. Sponges are an exception to this rule as they are animals with non-differentiated tissue. Most animals reproduce sexually, although some types are capable of asexual reproduction.
In addition, many types of animals are motile, or capable of independent movement. Some types of animals, however, are only motile at one point in their development, then remain fixed in one location for the remainder of the process. Animals are capable of movement so that they can catch prey, avoid predators and find the things they need to survive. Most types of animals ingest other organisms, such as plants or other animals, in order to obtain carbon for energy. Animals break these organisms down through the process of digestion, then convert the carbon into forms of energy that their bodies can use.