Vestigial

                                                    25. Vestigial

Vestigial refers to an organ that is not functional anymore, but used to be used by ancient ancestors. Vestigial organs provide a clue to what ancestors that animal or human was derived from. On my dog, his dew claw is a vestigial organ. A dew claw is the fifth claw on most dogs paws that is higher up on the leg than the other four claws. Most of the time his claw does not touch the ground and is useless is providing traction to the dog.