Tail regeneration in the Leopard gecko (Eublepharis macularius)

Like many other lizards the Leopard gecko, Eublepharis macularius, can drop off its tail when frightened via tail autotomy, and regenerate a new tail. Anatomically the tail consists of skin with fat and muscle tissue underneath, which envelopes the vertebrae with blood vessels and nerves in the centre. On selected places in the tail a “fracture plate” of connective tissue exists, which is visible on the outside as constrictive rings. This fracture plate is a predilected place for the tail to rupture; here the vertebra consists of demineralized zones and cartilage to ensure a smooth rupture without fractures, special connective tissue plates in the muscle and fat tissue ensure a smooth rupture and the blood vessels have sphincters to minimize blood loss. When the tail is dropped due to autotomy it will always be ruptured on a fracture plate, when the tail is ripped off, it can also rupture on a different location. As soon as the tail is autotomized a thrombus forms to minimize blood loss and to cover the exposed spinal cord. The tail regeneration starts immediately, this process can be divided in seven phases and takes up to 25 days. During the regeneration, new skin tissue that covers the wound is developed first, followed by the growth of new blood vessels. As the development of new nerve cells is impossible, axons from the nerve cells in the existing part of the tail are further extended into the regenerative tissue. This new spinal cord is then enveloped by cartilage and muscle tissue and the outer skin layer starts to keratinize and pigmentate. When the tail is fully regenerated it has the same diameter and colour as the original tail, but without constrictive rings as there are no new fracture plates formed. The regenerated tail has a smaller mobility range, and this impairs the movements of the gecko, which is visible as a change in locomotion and different tail movement. 

A Leopard gecko that has lost its tail needs special care, as it has lost its primary fat reserves. The animal needs to be put in a quarantine box with paper towel bedding, and has to be fed more often, preferable every other day, to prevent further weight loss. Feed the gecko by hand until it declines the offered insects, no live crickets should be left in the box, as they can harm the regenerating tail. Place a dish with calcium + vitamin D3 in the box and use UVB lighting as the animal needs to replenish the lost calcium from the tail vertebrae loss. Remove faeces daily to prevent wound infection. When the tail is fully regenerated the gecko can be returned to its original terrarium. However, if it has an aggressive cage mate it should be housed solitary from now on. Young animals may develop a growth retardation and their weight needs to be monitored.