A mouse is an example of an animal with bilateral symmetry. If an imaginary line were drawn from the tip of its nose to the end of its tail, one side would be exactly like the other.
Humans also show bilateral symmetry. The left side of the body is identical to the right. Many types of animals exhibit this trait. In fact, all members of the phylum Arthropoda have this characteristic. Arthropods account for 90 percent of all animals. In addition to bilateral symmetry, each of these organisms has an exoskeleton, distinct body parts and jointed legs. This phylum also includes insects, spiders, crustaceans, centipedes and millipedes.