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For tortoise, terrapin and turtle care and conservation

KNOW YOUR TORTOISE. (This series originally appeared in the Leicester Tortoise Society Newsletter.)

THE EYE.

Most of the tortoises commonly kept in captivity have bright black eyes, the main exception being box tortoises, whose yellow, orange or brown eyes blend in with the camouflage markings on their heads. Tortoises have good colour vision, even though unlike mammals there are no blood vessels on the retina. There are no tear ducts to convey tears to the nose, so if tears form they will spill down the face.

There is a third eyelid in the front corner of the eye, but this is usually only just visible. It becomes more obvious in dehydration or disease, due to slight sinking of the eye, often accompanied by incomplete opening of the eyelids. If one eye is completely closed, even when the tortoise is warm and awake, it must be opened to assess whether there is a problem underneath. It may be possible to do this by softening the lids with warm boiled water. This can also be used for easing the eyelids open if they are sticky after hibernation. Bear in mind that the upper lid is quite firmly fixed, but the lower lid is more mobile.

If there is a speck of plant material in the eye, you may be able to flush it out, using warm boiled water again. Alternatively, you might have to gently tease it out, after which the surface can be flushed with antiseptic eye drops such as Brolene, available from chemists. Stubborn specks may need veterinary attention. This is one of the reasons for not hibernating tortoises in hay or straw; in the worst cases, a seed could penetrate the cornea while the animal is shuffling around in its box.

Swollen eyelids on one side only may be due to an infection, or to an injury such as a scratch from a companion’s claw or a burn from a heat lamp. If both sides are affected, this could indicate Vitamin A deficiency. These conditions may be accompanied by debris in the corner of the eye, which can be flushed out, or by a white plaque on the cornea. Veterinary treatment is advisable.

Cloudiness or cataracts within the eye may be due to freezing during hibernation. This can cause feeding difficulties and other strange behaviour. Mild cases can return to normal in time, but may need hand feeding for many months. Make sure your tortoise does not suffer this fate by hibernating it in a well insulated box in a frost free place.

EAR, NOSE & MOUTH

THE EAR. Tortoises respond mainly to low frequency sounds, so if yours comes when you call it has probably glimpsed you or heard your footfalls. The eardrum is below a small circular scale just behind the angle of the mouth, which should be flat or slightly concave. Try to avoid too much pressure on this area if you need to open the mouth. Bulging may indicate an abscess, so seek veterinary advice. The middle ear is connected to the back of the mouth by the Eustachian tube, and pus may appear at the internal opening if infected.

THE NOSE. Tortoises have a very good sense of smell, for identifying food and also for locating the opposite sex. They breathe through the nose, so open-mouthed breathing usually indicates a respiratory problem. After eating succulent food, liquid may appear through the nostrils from the back of the mouth, but normally the nose should be dry. A watery discharge from both nostrils can be a sign of rhinitis or ‘runny nose syndrome’, often brought on by a sudden drop in temperature or by the introduction of a ‘carrier’ tortoise. Isolate the victim immediately, keeping it warm under a lamp for a few days. If this fails, antibiotics are advisable. If the discharge is gelatinous or purulent it is more serious. A discharge from one nostril only could mean a foreign body or a bacterial infection, and will also need veterinary treatment.

THE MOUTH. Hidden in the roof of the mouth is a sensitive patch called ‘Jacobsen’s Organ’, which assists in the keen sense of smell. A tortoise whose throat is pumping is circulating air through the nose and around the mouth to detect scent particles. Tortoises have a strong bite, but do not chew; they salivate and manipulate their food for swallowing. An overgrown maxilla or ‘parrot beak’ may interfere with feeding. It can be corrected by careful clipping (little by little to avoid splitting) and then filing; introduce tough food into the diet, such as cauliflower stumps. An undershot mandible or ‘bulldog jaw’ is caused by dietary deficiency or congenital misalignment, and may be impossible to correct.

The mouth and tongue of an active tortoise are usually a healthy pink, but this can vary depending on what it has eaten. Do not assume jaundice if your pet’s mouth is orange or brown; it may simply be stained by the sap of thistles or dandelions. If you open the mouth wide you can see the glottis behind the fleshy tongue, and if you ever need to pass a stomach tube for force feeding, it should slide easily over the glottis and down the oesophagus. After hibernation, there may be a white or yellowish deposit inside the mouth and on the tongue. This can usually be scraped off by firm pressure with a cotton bud, followed by a wipe with ‘Betadine’ antiseptic solution. If it has not completely disappeared within a few days, you probably have a case of stomatitis or ‘mouth rot’, so see your vet without delay. A tortoise that goes off its food should have its mouth examined, and if stomatitis is present immediate isolation and treatment are essential; it can be very infectious.

Try to practise opening your tortoise’s mouth – it’s a good idea to check regularly anyway, and if he gets used to it then you won’t find it so difficult if you really need to.

THE SKIN

The skin of the tortoise is modified in parts into protective scales, some of which can be quite thick. This is used for identification in some similar species, notably the horny tubercles on the inner thigh of a Spur-thighed tortoise, and the horny pin on the tip of the tail of a Hermann’s tortoise. You will find small spurs and a tail pin on a Horsfield’s tortoise, but neither on a Marginated tortoise. It is quite normal for scales and shreds of skin to peel off, especially in the head and neck area. The skin colour can vary slightly between species – for example, the Horsfield’s has a greenish tinge, so you can’t take this as an indication of ill-health unless you’ve observed the normal colour in a healthy animal. There are no sweat glands in the skin, so to cool down a tortoise will seek the shade.

Skin wounds in tortoises can take several weeks to heal completely, even at optimum temperatures. The most likely cause is a bite from an over-amorous male, with rats, dogs or foxes being other possible culprits. Clean the wound with water and apply ‘Betadine’ antiseptic solution, or 1% Crystal Violet solution to promote healing. In some cases antibiotics will be necessary. Never put a tortoise into hibernation with an unhealed wound, as bacterial or fungal infections are likely to take over. Wounds can become fly-blown in summer, so watch carefully for this, or keep the animal indoors for a few days until the wound has dried up. Pay particular attention to the cloacal area where abrasions can become soiled, especially in vigorous males.

If fly strike does occur the eggs or maggots must be flushed out or picked out with tweezers. Insecticides should be used with caution; 'Ivermectin' in particular is poisonous to tortoises. The only other skin parasite of tortoises is a type of tick not found in the UK, so you would only see this on newly imported animals. A lump under the skin is most likely to be an abscess, and will not go away without treatment. The pus is usually cheesy and cannot be drained, so the whole abscess has to be removed by your vet. Skin tumours are quite rare.

The claws are another skin modification which can be used as an identifying feature, as the number varies between species. Hatchlings can have the opportunity to wear down their sharp claws if given an area of 'budgie' sandpaper in their vivarium, but some may grow at crazy angles in which case the tip can be nipped off with sharp scissors. Adults’ claws only need clipping if they are growing abnormally or have become so long there is a danger of snagging. If you should accidentally draw blood, don't panic – firm pressure with cotton wool soaked in 'Betadine' will stop the flow. A torn claw will not always grow back – it depends on the degree of damage.

The beak can also be clipped if overgrown, preferably with pincer type clippers rather than scissor action, to avoid the risk of splitting. Finish off by gentle filing.

The rostrum is the area around the nostrils. A tortoise which frequently bangs its nose trying to escape from a glass-fronted vivarium may cause permanent damage, so if you have this problem adjust the accommodation so the animal can’t see out.

THE SHELL

The bony box of the tortoise is a unique feature which, as well as giving protection, also allows it to absorb heat from the sun and remain warm for longer than other reptiles. There is tremendous variation, ranging from the highly domed Starred tortoise to the flattened Pancake tortoise.

The shell consists of the carapace above and the plastron below, linked by vertical bridges between the front and hind limbs. There is a layer of interlocking bony plates overlaid by horny scutes, and between these is the growth region where keratin is produced to form the scutes. It is this layer which bleeds if the shell is damaged. The scutes are named according to their position relative to parts of the body, and there are about 54 in total, with congenital abnormalities in shape being fairly common. A growth ring is visible around the scutes, and is most obvious as a paler strip between the marginals and the rest of the carapace in animals up to about 35 years old. After this it becomes indistinct, as it also does in those tortoises which are not thriving. Some shells are hinged, as in the Box tortoises which can enclose themselves completely against predators (and owners!) and the Hingebacks which close their rear end for protection when partly buried. It is quite normal for there to be slight movement between the abdominal and femoral scutes of the plastron in some species, sometimes with a very pronounced groove.

In captivity, scutes can become domed due to overproduction of keratin, sometimes attributable to a diet too rich in protein. Some people moderate the diet by not feeding every day, and by allowing hatchlings to hibernate briefly as they would in the wild. Imbalance in the calcium intake can cause problems ranging from softening of the plastron to severe cases of osteodystrophy where the whole shape of the shell becomes contorted. This cannot be corrected once it has occurred, so to avoid this problem make sure you give dietary supplements with a calcium/phosphorus ratio of at least 1.5:1, adding even more calcium for juveniles in the form of limestone flour or crushed calcium tablets. Daylight is also essential for shell growth, so hatchlings should go outside whenever the weather is favourable, or have a carefully controlled artificial ultra-violet source such as a Powersun®, Reptisun® or Arcadia D3 Compact® reptile lamp. Adults benefit from an additional source of UVB in poor weather too.

Physical damage to the shell is a frequent occurrence, often from mating rituals but also by trauma from other animals, lawn mowers, bonfires, or simply by falling down steps etc. Tortoises can recover from quite horrific shell injuries. Minor damage will usually heal unaided after cleansing with Betadine and protecting from flies. Dog bite victims will need antibiotic treatment from your vet to avoid deep infection arising from puncture wounds. Serious damage and burns may need intensive care, and the lesions must be protected while healing takes place. This can take many weeks or months, and the fixative may be left in place permanently except in juveniles where it must eventually be removed to allow for normal shell growth. The scars from shell injuries are sometimes white where the bony layer appears at the surface. It is important not to let vigorous males cause shell damage to others by butting. It is quite amazing what serious abrasions some owners will tolerate, sometimes leading to shell rot or permanent damage to the growth ring. Such tortoises should be kept separately except during planned mating encounters. Shell rot can also start from less obvious causes, so if a scute appears to be soft or has liquid seeping from its margins, seek veterinary treatment.

Finally – to oil or not to oil the shell? Well, it wouldn’t get oiled in the wild, and a greasy surface attracts dirt, so just clean it with water.

LOCOMOTION

A healthy tortoise walks with its plastron clear of the ground, and the strength of its legs is legendary. Boulders or bricks can be heaved out of the way of a determined escapee, and it can squeeze into spaces from which extrication is difficult. The shoulder blades and pelvis are actually fused to the spine and shell, giving them tremendous leverage. The claws are also very useful for escaping, as owners with Hermann’s and especially Horsfield’s tortoises will know. Some can climb bushes or wire netting with ease, and even those finding it difficult may have the tenacity to succeed. Speed is dependent on temperature: a very warm tortoise can scuttle around almost at a run, particularly during a pursuit.

A sick tortoise may not have the strength to raise its body off the ground, and if it becomes very debilitated it may never recover the ability to do so. A weak tortoise may even appear to be walking backwards, but this is usually just an inability to get a grip, so you can help by experimenting with different surfaces. You can also help a weak tortoise by manipulating its joints, or by placing it on a brick when it is nice and warm so it will exercise itself in its struggle to get down. If a tortoise is just regaining its appetite after illness, put its food where it has to walk a little way to find it, rather than right under its nose.

Walking in circles can have several possible causes. For example, exposure to frost during hibernation may cause total or partial blindness, in which case the tortoise may slowly recover; or it may have suffered irreversible brain damage. Circling can also be caused by toxaemia, such as in severe liver damage from obesity, and occasionally by an abscess or tumour on the brain.

Even when hibernating, a normal tortoise should have good muscle tone, i.e. the legs should not be flaccid when you try to withdraw them. Hind limb weakness can occasionally be caused by direct injury to the limb, such as a bite or rubbing of the shell on the leg, but if both limbs are affected it may need a radiograph to pin-point the problem. This is particularly important in females where egg-binding can cause pressure in the abdomen affecting the nerve supply to the legs. The condition can also be caused by a compression injury of the carapace.

Swelling of the joints or feet can be caused by fractures, septic arthritis or occasionally gout. An X-ray is essential to determine the cause and get the correct treatment. Leg fractures can be immobilised and should heal in about 3 months. More serious injuries, or infections that have eroded the bone, may result in amputation, and there have been many ingenious devices to enable a tortoise to retain its mobility with only three legs.

THE TAIL

The tail is the best guide to the sex of an adult tortoise, rather than the concavity of the plastron, which can be misleading. The male’s tail is noticeably longer and more bulky, and the cloacal opening tends to be further away from the plastron. Of course, that still leaves a small number who are not typical, until that ‘male’ lays eggs or ‘female’ starts butting behaviour. Juveniles cannot usually be reliably sexed externally. An additional feature of the Hermann’s and Horsfield tortoises is the horny pin on the end of the tail.

The urinary bladder, the large intestine and the reproductive tracts all lead into the cloaca, which exits via the vent on the underside of the tail. To evacuate its cloaca, a normal tortoise raises its rear end slightly off the ground. If you see it repeatedly doing this, with no results, further investigation is needed. It may be trying to lay eggs if female, in which case you must quickly provide a suitable egg-laying area; or it may be constipated or have a bladder stone. Continued straining may cause prolapse of the uterus, bladder or penis, and there are other causes of prolapse too such as debility or infections.

In males, the testes are inside the body cavity and the penis is on the floor of the cloaca. It protrudes from the cloaca during mating, and the semen travels along a groove on the upper surface of the penis into the female. Sometimes the penis will not withdraw back into the male’s cloaca. Veterinary treatment may be needed to correct this, and if not quickly successful amputation may be necessary. The tortoise can still lead a normal life afterwards, though unable to mate.

A soiled tail is a prime target for fly strike if it becomes damaged, with the unpleasant consequence of having to remove blowfly eggs or even burrowing maggots. The female’s cloaca may be injured during mating attempts by biting or, particularly with Hermann’s tortoise, from the tail pin. A male tortoise normally has his tail tucked sideways under the shell, but if he doesn’t walk very ‘tall’ he may develop a sore vent if not kept on grass, so be aware of this if yours has access to a patio.

Another consequence of tail soiling, or of overcrowding, is the transmission of bacterial or parasitic infections, some of which can enter through the vent and can cause serious illness. In the wild, tortoises seldom encounter faeces from others, but in captivity even a lone tortoise can re-infect itself from a build-up of parasites. So do as much as you can to keep your tortoise’s enclosure clean.

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