 Some salamander species use tail autotomy to escape predators . The tail drops off and wriggles around for a while after an attack , and the salamander either runs away or stays still enough not to be noticed while the predator is distracted . The tail regrows with time , and salamanders routinely regenerate other complex tissues , including the lens or retina of the eye . Within only a few weeks of losing a piece of a limb , a salamander perfectly reforms the missing structure . 
