Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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How Your Reptile Changes His Wardrobe


Pet Column for the week of April 22, 2002


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Jennifer Stone
Information Specialist

If you have ever seen a snakeskin caught on a bush in the woods, you've probably wondered: Why do reptiles shed? How does it work, and what exactly do these cold-blooded beasts have under their discarded scales?

Reptiles grow continuously throughout their lives, but because their skin does not grow to accommodate their increased size, they must shed periodically. Dr. Julia Whittington, exotics veterinarian at the University of Illinois Veterinary Teaching Hospital, says, "Snakes usually shed their skin in one piece from head to tail. As the time to shed approaches, a layer of water forms underneath the outer layer of skin. This loosens the outer skin and separates it from the new layer underneath."

Shedding begins at the head, with the outer layer peeling back at the nose. The skin begins to come off from head to tail as the snake rubs along the ground and against objects in the environment. When the outer layer of skin finally falls off, it is left behind inside out.

Lizards, such as iguanas, geckos, and bearded dragons, don't shed their skin in one piece but in sections. Turtles, on the other hand, don't shed their soft skin at all, but shed the plates (called scutes) that combine to form their shell.

As tough as it may seem, reptilian skin is not invulnerable to skin problems. Problems with shedding can occur when there is too little moisture in the environment and the skin fails to become completely loosened from the underlying layer, leading to incomplete and patchy shedding. If the areas of skin that are left are not too extensive and do not adhere too tightly to the new skin layer, the reptile can be soaked in warm water and the old skin layer can sometimes be gently removed. Care must be taken not to damage the underlying skin layer. Manual removal of skin covering the eyes should never be attempted because damage to the cornea can occur.

"Right before shedding occurs, the skin begins to look cloudy. If the skin reaches this stage, then soaking your pet may not help make the shedding process go smoothly," says Dr. Whittington. "In this case it may be best to determine the optimal humidity for your pet and wait. The next shedding cycle should go more smoothly."

If incomplete shedding leaves skin remnants on the feet, cell death (necrosis) and sloughing of the feet can occur due to a loss of blood supply.

While too little moisture can have negative effects, too much moisture can be equally damaging to reptilian skin. A warm humid environment is a prime breeding ground for a host of bacteria, which can cause problems. Dr. Whittington says, "Reptiles in aquatic environments are especially prone to skin infections because they urinate and defecate into the water which is in constant contact with the skin. If the environment is not kept clean, infections can arise." Other factors that can increase bacteria in this type of environment are natural elements, such as plants and mosses, which in a closed environment foster an overgrowth of bacteria.

Semi-aquatic turtles that divide their time between land and water , such as sliders, are especially prone to a special infection called "shell rot." This is a bacterial infection that causes erosion of the shell. These turtles require water to swim in, but also need a dry area to sit on. "If a semi-aquatic turtle gets stressed, it may hide in the water and be reluctant to come out," says Dr. Whittington. "When this happens, it is the owner's responsibility to take the turtle out of the water to let the shell dry out periodically."

The best way to keep your reptile healthy is to research the needs of your pet. Talk to your exotics veterinarian and find out what kind of environment the reptile should live in and what the optimal humidity should be. Make sure you get a hydrometer to keep track of humidity levels. Most importantly, make sure that the environment that you choose for your pet is conducive to cleaning.

Dr. Whittington says, "Keeping a clean environment is the most important thing that you can do to ensure the health of your reptilian companion."

If you have any questions about reptiles or reptile skin problems, please contact your local exotics veterinarian.