Tail

The tail (also called seed or dabo) is a body part extending from the rear end of the body in many animals. It is typically a continuation of the backbone extending beyond where the abdomen and pelvis end. It consists of small bones joined together, muscle, nerve, and blood vessel; some tails lack bone entirely.

The tail does not serve a single function. Different types use it in different ways: balance, locomotion, air control during flight or diving, social communication, and protection of young. Its shape and size vary according to the lifestyle of the species.

Structure

In vertebrate animals, the tail usually consists of caudal vertebrae following the sacrum. The number of these bones varies widely: some species have only a few, others more than fifty. The tail's muscles control rotation, elevation, and lateral movement. In fish, the tail is comparable to the caudal fin and is the primary organ of water propulsion.

Functions

In fish, the tail provides forward thrust. In climbing and tree-dwelling mammals, it aids balance. In birds, the tail feathers function as a rudder, controlling direction and stability of flight. Many hoofed animals use the tail to swat away insects and parasites from the rear. In dogs, tail movement is among the signals of social communication observed between individuals.

Evolution

In some species the tail has reduced or disappeared entirely. In humans and large primates, only a small bone called the coccyx remains, a vestige of a former tail. Certain reptiles such as lizards have the ability to detach the tail when grasped, then regrow part of it—a survival mechanism.