Tail breaks and drops
Many lizards drop their tails as a defense against predators...
©1996, 2002 Melissa Kaplan
Iguanas, like many lizards, have evolved a defense mechanism wherein they can drop a section of their tail. The skin, muscles, blood supply, nerves and bone separate at almost any place along the length of the tail (below the reproductive organs). The tail lays flopping in the predator's mouth or on the ground. While the predator (or harasser) is thereby occupied or distracted by the flopping, wriggling tail, the lizard makes its get away.
The lost of the tail (called autotomy) may be natural, but it is stressful to the lizard, especially if that lizard stores critical fat deposits in the tail, such as leopard geckos. Not only do they need to spend energy healing the stump and regrowing the tail, but the loss of fat may occur at a critical time, such as during gestation or a period of low food availability.
There is not much to do be done if your lizard loses its tail other that to keep its enclosure spotlessly clean, provide lots of nourishment and make sure the thermal gradients and photoperiods are running correctly. The less additional stress the lizard has to deal with, the faster the stump will heal and, if the tail is going to regenerate (they do not always do so), it will do so fairly rapidly.
During healing, the exposed muscle bundles will fold over the exposed bone. They will continue to dry out, forming a rigid cap protecting the stump. Skin will then start to grow over it.
Tails will generally regenerate, especially if the lizard is still small. It rarely grows back the same length or color. In iguanas, the regrowth is generally a dark rubbery black to start, then, as the scales regenerate, they usually come in a dark chocolate brown, with very small scales, sometimes sandy or gritty in texture. Sometimes they may be green or have smears of green through the brown. The dorsal crest does not regrow. In other lizards, the color may be different, and the final regrowth may be smeary or the patterning run the wrong way.
Once a reptile has been treated, care must be taken to provide a supportive environment to promote rapid, uncomplicated recovery. Temperatures towards the higher end of the reptile's preferred optimum temperature zone should be provided (don't drop them as low at night, but do turn off the basking temps at night). Good nutrition and adequate intake must be maintained; nutritional deficiencies, such as hypoproteinemia and hypocalcemia, will delay the healing process, with the latter affecting the healing of broken or weakened bones. The environment must be kept as clean as possible during recovery to insure the least amount of contamination of the wound sites. In this case, keeping the enclosure setup simple, easy to clean and disinfect is of paramount importance. While more natural substrates may need to give way to medical needs, necessary furnishings such as hide boxes must still be provided to reduce psychological stress.
Do work with the tail as part of your taming and socializing process - it will greatly reduce the chances of him dropping it defensively: the tails can be dropped without actually being grabbed or even touched.
If the iguana is big enough to not need the drop-defense anymore, it won't expend the energy to regenerate the tail - instead, all that energy will go into increasing body size.
I never realized just how much igs depend upon their tails for balance...Wally wobbled for a couple of weeks climbing vertical surfaces up and down (down especially) until he found his new center of balance. He did, however, develop a major case of tail envy and went around attacking everyone else's tail.
A Note on Incomplete
If the break is through the bone but not all the way through the tail, or the stump becomes infected, it is best to remove the tail just above the break. Most reptile vets will carve out a little bone and muscle and then pull the skin flaps over the stump, stitching it in place. This will help reduce the risk of infection. It will not prevent the tail from regenerating - if it is going to grow back, it will grow through the sutured skin.
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