Shell Problems for Tortoise Keepers

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Shell Problems for Tortoise Keepers

Tortoise shells are a key factor that makes tortoises so interesting, but they are subject to some conditions that the keeper needs to know how to respond to- 'MBD' (Metabolic Bone Disease), pyramiding, 'shell rot', and minor injuries.

It is fairly easy to tell which is which. Injuries are generally obvious. MBD makes the shell soft and deformed, pyramiding causes the scutes on the carapace to grow in a conical or hilly fashion, and 'shell rot' eats away at the scutes on the carapace or plastron.

The term 'Metabolic Bone Disease' (or 'Disorder') is not an actual disease, but a catch-term for a wide variety of things that can soften or deform a tortoise's shell and skeleton. Some MBD's are due to disease processes, like 'Fibrous osteodystrophy', 'Hypertropic osteopathy', 'Paget's Disease', etc. Most MBD's are due to problems with diet and basic cares. The most common is 'Nutritional Secondary Hyperparathyroidism' or NSHP. Common names for this condition are 'rubber jaw' in lizards, or 'soft shell' in turtles and tortoises. The root cause is usually a combination of too little calcium, too much phosphorous, or too little vitamin D.

The more you study it, the more amazing the calcium cycle is. Calcium, phosphorous, magnesium, iron, water, some dietary vitamin D, vitamin A, and other nutrients and water are taken in the diet, and light with a wavelength around 296nanometers (UVB, almost UVC range) is absorbed through the skin. The liver, kidneys, parathyroid glands, and ultimobranchial glands process chemicals, converting calcium and other ingredients to a form that the cells can absorb and use. It is a fairly intricate balance and all ingredients have to be in place for everything to work correctly. You can offer all the calcium you want, but without the other necessary elements, it won't help at all.

Since NSHP is almost entirely due to poor cares and diet, it can be prevented by providing the tortoise with the proper cares and diet, appropriate to the species. A diet with enough calcium and a good ratio of calcium to phosphorous, in an average ratio of between 1.5:1 and 2:1 is a good foundation. The tortoise should also be provided with unfiltered sunlight as much as possible.

UVB can be difficult even for experienced keepers. The problem is that evidence suggests that most reptiles need at least some exposure to good sunlight, and that no bulb perfectly replaces what the sun does. Many UVB bulbs do not emit enough of the right wavelengths to really help, and as far as we can tell, dietary vitamin D does not help reptiles as much as sunlight does. On the other hand, we really do not know what role dietary vitamin D2 has, or what the real vitamin D/UVB needs really are for most reptiles.

The tortoise also needs proper warmth, plenty of exercise, good rest, an assortment of other vitamins and minerals, etc.- in other words, good general cares and diet.

NSHP shows up in tortoises as a softened, leathery, or rubbery shell*, but by the time the shell shows obvious problems, there may be problems in the bones. Things like deformed jaws, weak and/or deformed limbs, splayed walking/dragging, paralysis, and cloacal prolapses are signs something is wrong. Be cautious, though, since a.) some of these symptoms can also signal other issues, and b.) these symptoms may be delayed as the tortoise 'steals' calcium from the shell to protect the skeleton and nervous system.

(* Note: Some turtles and tortoises are supposed to have soft, leathery, or rubbery shells such as the Pancake Tortoise and Soft-shell Turtles.)

Very young tortoises are a bit soft or flexible so they can fit in the egg and so the shell can move as they grow. This often worries keepers, but there is a difference between a young shell and a soft shell. Young tortoise shells are springy, like they are made of a stiff plastic- the plastron may feel a bit springy for some time. Soft shells, however, feel more 'leathery' and do not resist being compressed as much. If the shell just gets softer instead of firming up, you should take action.

As long as the tortoise is still eating, the shell is not too soft, and there are no other worrisome symptoms, the tortoise can probably be treated at home. Do not, however, suddenly start dumping lots of calcium in the poor animal or flooding it with UVB lighting. Instead...
- Work to provide the proper habitat, temps, humidity, and lighting.
- Correct the diet, adding more calcium-rich foods.
- Add a small amount of extra calcium, as a fine powder or liquid, to the diet.
- Add a small pinch or drop of multivitamins once a week or so to help ensure the tortoise is getting the other trace elements it needs.
- Offer good UVB lighting with either natural, unfiltered sunlight or a good UVB bulb. Currently, mercury vapor bulbs (MVB) that are tuned to emit UVB seem to be the most sun-like option, especially if you pair it with a cool-white fluorescent or plant bulb to provide a more balanced color spectrum.

If the shell is very soft; the tortoise is not eating; is showing other symptoms; or is not responding to your cares, you should see a vet. The vet should do blood and other tests, an x-ray, and take a complete history to try to determine if the problem is NSHP or another bone problem. The vet would then determine a course of treatment based on the findings. NSHP is usually treated with vitamin D3 injections and supplemental calcium orally, then follow-ups over two weeks. More severe cases may also need dietary support and other treatment. It is important to follow the vets suggestions as carefully as possible for the best chance at recovery.

Treated intelligently, the tortoise should recover fully, although some shell or skeletal deformity may remain, and there may be residual muscle or nerve problems. The earlier it is caught, the better the chances for a complete recovery. NSHP is rarely fatal by itself, but it can weaken a tortoise and other problems can develop.

When scutes grow in a conical or piled-up fashion with the bone deforming behind the scutes, we call it pyramiding. Some tortoises, such as Star Tortoises, pyramid naturally, and some tortoises, such as some Testudo species, seem a little more resistant to the problem. As common as the condition is in captive tortoises like Sulcata, Leopards, and Red-foots, there is very little hard research on it. This article is based on the best information available, but I am not going to even try to claim that it is the last word on the subject.

Pyramiding has been blamed in the past on excess protein in the diet, but now attention seems to be focused on a two-prong approach- humidity and early growth patterns/diet. Experiments by people like Richard Fife and Tom Roach have shown that keeping a growing tortoise's shell misted throughout the day helps prevent pyramiding, but a counter-argument is that this causes thinner scutes and does not address the shell issues beneath the scutes- pyramided shell and spongy bones with a lower than usual density.

Douglas Mader, DVM, believes that a high calorie diet (which is also almost automatically low in fiber), and lack of exercise plays a role, as does inadequate temperature control, etc. Tom Roach and others feel that adequate calcium and sunlight has an important role. This may help explain why keepers who cannot keep their animals outside for much of the year seem to struggle with pyramiding so much. Andy Highfield of believes that too-rapid hatchling growth is a key issue, possibly combined with as-yet unknown dietary issues.

We will also note that pyramiding and more severe forms of MBD often occur together, especially with long-term poor cares. If the shell itself appears flattened, soft, 'collapsed', etc., then the NSHP form of MBD is probably involved as well.

A two-pronged approach is probably best. Keep the tortoise's shell from drying out, especially in the first year. Misting, humid hides, etc. are helpful. Make sure to control temps correctly, and be aware that some species, such as Red-foots, can develop shell rot if there are in contact with some forms to too-wet substrate for too long (see 'Shell Rot'). At the same time, avoid overfeeding young tortoises, and avoid overly 'rich' foods. Proper environment and daily cares are also important, and real sunlight probably helps.

The first signals of pyramiding may be thick growth rings or a deepening grove between the scutes instead of the normal smooth growth. Additional new growth will add more height to the previous layers if things are not corrected and grooves or valleys will start to develop between scutes. While pyramiding usually happens early, it can start to develop later in some species (like Red-foots) if conditions allow.

There is no way to eliminate pyramids once they start. Treatment focuses on preventing further pyramiding by doing those things that prevent pyramiding. If things are corrected, new growth will be reasonably flat- although it may take years to see a significant difference. See 'Prevention'.

Pyramiding by itself is mostly a cosmetic issue and should not, by itself, be considered a sign of failure. Pyramided tortoises live as long and successful a life as those without pyramids. Because it represents a flaw in our cares or understandings, we want to continue to learn more about it and continue finding ways to prevent it.

This is another 'catch-all' term for a variety of conditions that can include bacterial, fungal, or environmental factors. In most forms of shell rot, micro-organisms get under the protective layers of the scutes and begin to 'eat away' at the tissues they find there. This means that there needs to be a pathogen in the habitat, and usually some form of damage to allow it to get under the top layer of scutes. An example of a specific form of this type of shell rot is Septic Cutaneous Ulcerative Disease (SCUD), which is caused by the bacteria Citobacter freundii, most often associated with shellfish.

- Minimize the growth of bacteria, viruses, molds and mildew in the habitat.
- Arrange things to minimize scratches, abrasions, and chips to the shell.
- Prevent overly-wet substrates, especially acidic materials such as mosses, and especially for susceptible species like Red-foots. These conditions can lead to environmental 'rots' that behave like 'immersion foot' does for humans.
- Many forms of shell rot are infectious, so new animals should be quarantined and if one animal shows it, all animals should be monitored.

All forms of rot will show damage to some or all of the layers of scute material. More severe forms of rot actually loosen scutes and cause them to slough off. You may be able to determine the cause of the rot by other symptoms:
- Bacterial 'rots' often show pitting, black deposits, and a bad smell.
- Fungal 'rots' often show a cheese-like material that may look fuzzy up-close growing in and around the eroded or damaged area.
- Environmental 'rots' cause over-saturated scute layers to swell up and rub off with no other sign of damage.

NOTE: Any form of shell rot can invite secondary infestations and infections. Consider any form of rot as a serious condition. The deeper or more widespread the rot is, the harder it is to treat at home. Some forms of shell rot can lead to bone or blood infections, and may be quite dangerous.

- Remove the affected tortoise(s) from the habitat until the habitat can be cleaned and disinfected.
- Clean the affected area with gentle scrubbing or scraping to remove loosened materials. Try to remove any dead, dried-out, or damaged scute materials, but do not force anything.
- Swab the area completely with a multipurpose skin disinfectant such as Betadine Solution. Let dry completely. Betadine is effective against many micro-organisms, but also inhibits healthy growth so do not use it past the first 2-3 days cleaning. (This may be all some very minor forms need, especially minor environmental rot.)
- Treat the affected area with a triple antibiotic ointment. Keep the tortoise on newspaper or paper towel for an hour or so to let the ointment work.
- Repeat Betadine and antibiotic ointment for 2-3 days.
- If there are signs of improvement, stop using the Betadine, but continue to use the antibiotic ointment until there are signs of healing.
- If there is no sign of improvement after the first few days, try an anti-fungal ointment, such as that sold for human foot use. Again, keep the tortoise on newspaper or paper towels for about an hour to allow the ointment to work.
- Continue using the anti-fungal ointment for a few days.
- If the anti-fungal works, continue using it daily until there are signs of healing.
- If the anti-fungal does not help, see a vet or expert.

Most forms of shell rot, caught early and treated aggressively, should be OK although it may take months or even years for some of the shell damage to fully heal and there may always be scars.

Tortoise shells are both very tough, and are designed to get hurt by predators- absorbing all the abuse the body would otherwise have to deal with. Many shell injuries can be treated at home but you should see a vet or an expert if the shell is cracked through, there are pieces missing, or there are holes into the body cavity.

Most shell wounds can be treated by a careful cleaning, gently removing loose parts (but do not force them). Swab the damaged area with Betadine Solution and let dry. Apply a triple antibiotic ointment to any raw areas. You can apply a sterile gauze pad to the wound and use paper tape to protect the shell, then use electrical tape on top of the paper tape for strength and protection.

If the damage leaves a very sharp edge, you can gently file it down like you would a fingernail.

Give the tortoise plenty of warmth and quiet to help it recover afterwards.

Most of the information in this article came from Dr. Douglas Mader's “Reptile Medicine and Surgery”. The author is not a vet, and this article is not meant to replace proper veterinary care.

Mark Adkins, Omaha NE, © October 29, 2010

Additional Resources:
- Richard Fife, Pyramiding in Tortoises,
- Tom Roach (AKA “Tom the Dog Trainer”,, etc.) Personal correspondence and posts, especially on the section on pyramiding

A special word of thanks to Tom for his help in reviewing and contributing to the article- it was incredibly helpful!

Discussions about this topic can be viewed or added to by visiting the Shell Problems for Tortoise Keepers discussion thread.

Edited by the author November 23, 2010 to update the Pyramiding section and clarify a few things elsewhere.
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