Reptile Skin Shedding
Snakes, Lizards and Chelonians
©1996, 2002 Melissa Kaplan
All animals, at regular intervals, shed their skin. Some, like humans, do it relatively unobtrusively in a sort of ongoing process (we shed 1.5 million skin cells every hour with a new skin surface every 28 days or so). Others do it quickly and cleanly, like the one-piece sheds produced by snakes and tarantulas. Most lizards are rather more leisurely about it, with their skin coming off in patches. Some lizards are like snakes, tarantulas, and stick insects: they climb out of their old skin, leaving it behind in one piece.
If the terrestrial chelonian is too dry, the skin may hang like tattered rags, waving in the breeze made as the chelonian walks around. A quick spray with water, or a chance to wallow a bit in a shallow pan of water is generally all that is needed. Do not let species from arid climates do a lot of soaking. Some, like Russian tortoises, seem to be "programmed" to take as much time soaking as possible whenever water is available, as it is not often available in their native range. Provide a constant source of soaking water for them, and they will stay in it to the point of causing shell rot. Some species of tortoise and other terrestrial chelonians may take advantage of more humid microclimates in the wild, burrowing under plants, digging into the earth around their roots where moisture may be retained long after it has dried up on the surface of the ground. These species may benefit from the occasional wallow, soak or spray when they appear to be having problems shedding.
The skin of aquatic species, on the other hand, hangs off of the limbs, tail, neck or head in a sort of filmy flag until it finally tears completely away.
The skin covering the bony scutes also shed off. These are more often seen in aquatic species, found by panicked owners who spot them at the bottom of the tank or see them in mid-shed.
The skin on their eyelids will also shed off. At one point in the pre-shed period, you may walk in to find your iguana has suddenly turned into some wild, bug-eyed monster. Lying quietly, its closed eyes are puffed out 2-3 times their normal size. This is quite natural - they are puffing them up with air as a way to loosen the old skin. In a few days you will notice them rubbing their closed eyes against any handy surface as they begin to loosen and rub the skin off. Gentle head rubs, with your thumb and finger sliding over the closed lids, are particularly welcomed at this time.
If you do not regularly bathe or spray your iguana with water, you may wish to do so during pre-shed and shed periods. In the wild, the natural humidity in the air and the free access to rivers and streams helps the oily fluid build-up between the skin layers keep the old skin soft and supple as it peels off. In our much drier captive environments, the loosened pieces may dry out too quickly, resulting in a much slower shed. Spraying with plain tap water is all you need to do; the expensive vitamin and moisturizing sprays are of unnecessary and not any better than plain water in a $0.99 spray bottle.
Often times, spikes need help to shed completely; gently working at them over the course of several days, loosening the skin at the base and spraying them with water will help. If shed is left on, it may constrict the growth of the living tissue from which the spikes are made, resulting in the tissue dying and the spikes falling or breaking off.
The same problem can happen with toes and the narrow tail ends. If old shed is not removed, it can constrict the toes and tails, killing the tissue by strangling the nerve and blood supply that feeds it. Many books and vets claim that carpet fibers are dangerous for this reason yet, in all my years of free-roaming iguanas on wall-to-wall carpeting, I have never had such a problem. I have taken in many iguanas, however, with two, three, up to five layers of retained skin shed on toes and spikes...many of who lost toes and spikes as a result. Part of your regular weekly, if not daily, overall examination of the iguana should be checking toes, tails, and spikes to ensure that they are clean, free of skin, fibers, and human or pet hair.
Sometimes the grommet-shaped pieces of skin around the nostrils may not come off and, as your iguana nears its next shed, you begin to hear a sort of distant whistling sound as it breathes. After the next bath, work at this area gently to remove any such retained shed.
A healthy iguana will shed every 4-6 weeks. Iguanas aged 2-3 years may easily shed more often. It is not uncommon to have an iguana be in the middle of one shed when the next shed starts. During these times, they seem to be little more than skin-producing machines, inhaling food and producing prodigious amounts of both poop and mounds of shed. It is common for such growth to slow down during our winters, and during this time of slowed growth and reduced food intake, iguanas will often not shed. Where I live in Northern California, the last shed usually occurs in November, with the fist shed of the new year occurring in January or February, depending upon our weather patterns.
If your iguana is not shedding, and it is not the winter slow-growth period, then there is a problem. It may be that the environment is wrong, the diet is not nutritious enough to promote growth or normal skin renewal processes, or your iguana is sick. The iguana may also be psychologically stressed. A review of the environment and diet is necessary, as is a review of any other factors that may affect how the iguana responds psychologically/socially to his environment. Slow growers should also be seen by a reptile veterinarian to ensure that they are not suffering from bacterial infections, parasite infestations, or other medical problems.
Like iguanas, other lizards with movable eyelids will puff out their eyes in the days before their head shed starts. This can be particularly alarming, especially on chameleons (Chameleo, etc.) whose already large, protruding eyelids may swell to several times their normal size, immediately deflating when gently touched.
Many lizards who, in the wild, live in more arid areas are often kept too dry in captivity. In the wild, they would make use of more humid microclimates, burrowing down into the sandy ground, or heading into rocky crevices or burrows where moisture remains despite the heat of the day. In captivity, we also need to provide them with these microclimates, either by keeping a patch of sand or other substrate damp (as for many agamids), or by providing an easily accessible humidity retreat box.
In the wild, some larger lizards (monitors and tegus, for example), will soak in standing water or in river shallows. In captivity, standing water can be provided by putting into their enclosure a tub of water bowl, one large enough for the lizard to comfortably sprawl in, but deep enough so that when the lizard is fully submerged, the water doesn't overflow the tub and soak the enclosure. With large lizards, the need for such a water tub must be accounted for when designing and building an enclosure for the lizard.
Small to medium sized snakes (up to 5 feet / 1.5 m) snakes can instead be provided with a humidity retreat box, either as a permanent fixture in their enclosure, or one that is put in when the color changes associated with the start of the shed period are noted.
Snakes will also undergo color changes prior to a shed.
Boids (boas and pythons) will tend to grow dull, then get darker, sometimes becoming so dark that it is hard to differentiate their normal markings from a distance. Those boids with normally light colored bellies will often show signs of reddening and increased blotching of the belly scutes. This is normal in boids, especially pythons. Unfortunately, it can freak out the unprepared keeper as a reddening of the belly scutes is also an sign of advanced septicemia (systemic infection) and Salmonella. A good rule of thumb as to when to panic and when not to is if the reddening belly occurs in conjunction with an overall pre-shed darkening and associated behaviors, don't worry. If the reddening happens without the pre-shed color changes, and/or in conjunction with other signs of illness, worry and make a vet appointment.
Most colubrids lighten up a bit, getting a milky cast to their skin, including their bellies. Sometimes you will notice a dulling of the skin on their back and sides; a look at their belly will tell you that it is a pre-shed change as the belly starts to gray or lighten up.
Snakes go through a several day period where their eyes cloud up as the fluid builds up between the old and new spectacles. At its peak, the eyes are milky white with a bluish cast to them (called "white" or "blue"). Once the eyes clear, the snake will soon be ready to start its shed. I have found that if I bathe a snake (in a warm bath, for 15-20 minutes) the day the eyes are clear again, it will shed completely within the following 24 hours. I bathe the large snakes in the bathtub rather than wrestle a tub full of water into and out of their enclosure; smaller snakes are left to use their water bowl or humidity retreat boxes ad lib.
Many snakes will defecate at the same time that they shed. Before reaching in grabbing a handful of shed skin that is partially obscured by substrate or furnishings, you might want to check it out first...or always wear a glove!
A cautionary note of snake skin sheds: It is estimated that between 16-92% of snakes carry one or more serotypes of Salmonella (tables and citations can be found in my Salmonella Precautions article). Researchers in one university laboratory found viable Salmonella organisms on skin sheds that had been hanging in their lab for years. Since testing for Salmonella is not very effective, use caution when letting anyone who is at high risk for salmonellosis come into contact with snake skin shed or in contact with anyone who has been handling shed skin.
Always check your snake's head shed to make sure that both eyecaps ("spectacles") have come off. If they have not, take steps to removed the retained eyecaps.
While reptiles may still eat when in the very early phase of the pre-shed period, as the period progresses, they usually lose their appetite. Most greatly reduce their food intake; others stop eating altogether until after they have shed. Some snakes will not eat while their eyes are milky; some will take a meal once the eyes have cleared but before they shed, while others will not eat until after they shed.
A problem shed is a sign of an even greater, underlying problem. New snakes, especially imports, typically have poor sheds their first one or two sheds in captivity. The import and pet store process is less than healthy and stress-free, and so their sheds reflect that period of prolonged stress (psychological as well as environmental). Once they are housed properly, treated for dehydration and parasites, and begin to psychologically acclimated to captivity, they become healthier, and by the third shed, should be shedding properly - quickly and in one piece.
The same problems may be seen in sick and stressed lizards, especially imported ones. While their skin may normally come off in patches, instead of the shed being completed within the usual 1-3 weeks it would take for a healthy lizard, it may go on for months, with areas never shedding at all. (I took in a savanna monitor one time who had five layers of shed embedded on its back and head!)
When a problem shed occurs, or one that is too slow to start or finish, you need to figure out why it is happening and correct the problem:
If the reptile has started, but not properly completed, a shed, you can help it along:
If your reptile is having a problem shedding, troubleshoot the environment and the animal's overall health status. Fix the physical and social environment and get the reptile healthy, and problem sheds are simply not an issue.
shed 2-4 times a year.
As with full-grown humans, full-grown reptiles will continue to shed regularly as their old skin is ready to slough off to be replaced by the newly formed layer underneath.
If you pull
off shed that isn't ready to come off, you will cause mites.
The only way for your reptile to "get" mites if you pull of skin that isn't ready to come off is if your reptile's environment is already infested with mites. There may be so few that you haven't noticed them yet...but given the right environmental conditions-and easy access to food-they will multiply with abandon. If there are no mites in the environment to begin with, there won't be any mites after you impatiently pull off a piece of shed that you shouldn't have. But your over-eagerness to be helpful will still make the iguana uncomfortable, so restrain yourself!
If you missed Nova's Odyssey of Life: Part II rent or borrow it to get a close up view of the microcreatures such as the skin-eating mites who share our environment--and our bodies! Another look at these fascinating creatures can be found in Furtive Fauna: A Field Guide to the Creatures Who Live On You , by Roger M. Knutson.
The Vets Say
Douglas. R. Mader,
DVM. Dysecdysis: Abnormal Shedding & Retained Eyecaps. p 368-370
...The best method to remove tattered skin is to soak the snake in tepid water in a container deep enough to cover the snake's body but not so deep that the animal drowns. Never leave a soaking animal unattended!
Some people advocate adding various medicines to the soaking water, but in the author's opinion, plain water is usually sufficient. If it becomes necessary to add an agent to the water, such as an antibacterial agent, then a diluted iodine solution (e.g., Betadine) can be used. The recommended dilution is approximately 1:50 (iodine:water), resembling weak iced tea. If the container being used is clear, you should be able to read newsprint through the dilute Betadine. If this is not possible, then the solution is too concentrated.
Stephen. L. Barten,
DVM. Lizards. p 324-332
The species, age, state of nutrition, reproductive status, parasite load, hormonal balance, infection with bacterial or other skin pathogen, ambient temperature, and humidity may have an effect on the frequency of ecdysis.
John V. Rossi, DVM.
Dermatology. p 104-117
One of the practical applications of this process is the increased permeability of the skin during the growth and shedding phase. Snakes sprayed with anti-mite medications at this time appear much more susceptible to such toxins than those sprayed at other times. Hence the use of topical insecticides should be sharply curtailed at this time. Another observation is that severely malnourished snakes and lizards appear to have a very difficult and irregular slough (dysecdysis). This is likely due to the fact that hypoproteinemic animals are unable to produce the full complement of enzymes necessary to complete the breakdown between new and old epidermal generations. Further more, this may explain why excessively dry environments retard normal ecdysis. Drying out the fluid in the cleavage zone compromises the enzymatic and lubricating action of the fluid, hereby resulting in an incomplete separation.
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