Had just put the cans in the back of my van when I happened to look down on the ground and noticed that I had a "little" unexpected company. A lizard, looking pretty similar to the one in the accompanying photo, was lying on its back near the track where the bottom of the door to my shed rests all the time. The one thing that first grabbed my attention was the fact this lizard was missing most of its tail.
However, I also didn't observe any movement in the little critter at first, so I lightly nudged him and got an immediate response. Despite all of its movement, though, the lizard appeared unable to right itself. With a little help from me, it soon was on its feet but didn't go anywhere. There was some head movement, and I could see it kept opening and closing its mouth...but that was all.
After moving the little fella to a safe location, out of my way, I went about doing the job I had planned to do all along. As I was getting ready to come home, I checked on the little critter and found that he no longer was where I had placed him. Subsequently made a mental note to go online and see what, if anything, I could find out about tail-less lizards.
My research revealed that tail loss is called "tail autotomy," "caudal autotomy," or "tail-shedding." Many species of lizards are able to lose part of their tail to help them escape from a predator. The broken part of the tail falls to the ground, where it continues to wriggle like a living creature, distracting the predator away from the lizard's vulnerable body, sometimes for as long as five minutes. This distraction allows the lizard to escape while the predator is left holding or trying to catch the detached tail.
Since lizard tails often are used to store fat, they will provide some energy to a predator that eats it, and this might help the lizard by keeping the predator from searching for it again. Some lizards, such as skinks, also are known to eat their own severed tails for the energy stored in them.
Some lizard species can voluntarily lose their tails, even if little external force has been applied to the tail. They accomplish this by contracting muscles at the base of the tail, which break the vertebra. Often, though, the tail loss is the result of a predator grasping the tail and breaking it. Sometimes a lizard will thrash around a damaged or partly-broken tail until it breaks off completely. It's hard to know if a lizard is intentionally trying to detach its tail, but it often appears so.
Losing the tail does not seriously harm a lizard and may save its life, but the loss of a tail might have some negative effects besides a loss of stored energy. It could impair the lizard's ability to run quickly or balance itself while climbing. Further, a male lizard's attractiveness to the opposite sex might diminish with its social standing. Tail loss in juveniles also can delay growth and sexual maturity.
Broken tails do grow back, but these regenerated tails often are not as long as the original. Regenerated tails are made of cartilage, instead of bone, but they also can be broken off. It is not uncommon to find lizards in the wild with no tail or with a partly regenerated tail, so tail autotomy apparently works.
The tail of a juvenile skink usually is bright blue or pink. This helps the tail to be more visible to predators, which lets the lizard use its tail-loss defense. But the bright color on the tail often disappears when a juvenile becomes an adult. This is because adult females need the extra energy stored in the tail for the production of eggs or young, and adult males need the energy to court females and fight off other males. The needs of reproduction become more important to adults than the extra survival benefits of the tail-loss defense.
For that reason, everyone who handles a lizard always should be careful of the tail while handling one of the little creatures.
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