Anorexia in Snakes

Anorexia is the loss of appetite or refusal to eat. It can be a health problem in itself or it can be a sign of underlying problems. If your snake shows other signs of illness such as weight loss, depression, abdominal swelling, vomiting, diarrhea, sores in the mouth or on the skin, wheezing, abnormal discharges or abnormal posture in addition to not eating, there is a good chance that your pet is seriously ill and you should take him to a veterinarian who is experienced in reptile care.

Except for some female snakes just prior to egg laying and snakes undergoing planned hibernations, it is not normal for captive snakes to refuse to eat for more than one to two months. Many snakes from temperate climates tend to decrease their feeding rate in the autumn as the light cycle decreases. If your snake is healthy, you may just want to decrease feedings for the cooler months, but you should be vigilant to ensure that as the light cycle lengthens your snake’s appetite returns. Many owners whose snakes significantly slow down for the winter season elect to hibernate them. When snakes are prepared correctly for hibernation, it may be preferable to keeping them active for the winter.

Snakes often go off feed temporarily prior to shedding. When their skin is grey, they cannot see very well and often appear to be irritable. Once the shed is complete, the appetite should return to normal.

Wild caught snakes that are not used to living in captivity or eating domestic prey animals often suffer from anorexia. Newly acquired snakes and shy, retiring species such as ball pythons often refuse food until they become used to their new cages and owners.

If anorexia is allowed to continue for more than a few weeks, however, it can predispose the animal to infection. Severe, possibly non-reversible liver and kidney damage can occur if anorexia is allowed to go on until the animal has lost a significant amount of weight. Anorexia is a sign that a snake does not feel secure enough in his cage to eat. This is a strong indication to improve husbandry and reduce stress.

Diagnosis

Unless your veterinarian finds an obvious cause for anorexia on physical examination, such as mouth infection, pneumonia, or parasite infection, a detailed history is extremely important. If your snake has produced a recent stool take it with you to the veterinarian, so that it can be tested for parasites.

If your snake has not eaten for more than one to two months depending on the size and age of the snake or has lost significant body condition, further diagnostic tests are warranted. These include:

• Hematology (analysis of red and white blood cells)
• Serum chemistries (evaluates organ function)
• X-rays
• Cytology (microscopic examination of discharges or small samples of tissue)
• Specialized fecal analysis
• Bacterial or fungal cultures

Treatment

If husbandry problems are diagnosed and the snake appears healthy on physical examination, treatment is aimed at improving his environment and removing any intestinal parasites that may have been diagnosed on a fecal examination.

If your reptile has not eaten for awhile, he is probably dehydrated. It is important to rehydrate the snake prior to attempting to feed him. Depending on the severity of dehydration and the level of kidney and liver function, your veterinarian may select to rehydrate your snake with oral fluids given into the stomach with a feeding tube, subcutaneous fluids (under the skin), or intraperitoneal fluids (fluids given with a needle right into the abdominal cavity). In extremely severe cases, your veterinarian may want to hospitalize your snake and administer intravenous fluids.

Once your snake is rehydrated, it is important to start a series of tube feedings that are geared to prepare the intestines to digest real food again.

Concurrent treatment of any underlying medical problems, such as bacterial infections, obstructions or organ dysfunction, is crucial to the successful treatment of anorexia.

Home Care

Administer fluids, food supplements and medications according to your veterinarian’s instructions. Also, observe the general activity level and interest of your pet. Note the character and frequency of stools. Contact your veterinarian if you notice regurgitation. This is a sign that the medications or the feeding regime needs to be updated. In addition, do the following:

• Schedule regular veterinary visits to monitor the condition.
• Use a thermometer to measure the temperature gradient in the cage. Just feeling cage surfaces is not precise enough. Adjust heating devices to maintain a temperature range recommended by your veterinarian.
• Make sure that your snake gets a proper light cycle. Usually 12 hours light to 12 hours of dark is recommended for tropical species and 10 hours of light and 14 hours of dark in the winter and 14 hours of light and 10 hours of darkness in the summer is recommended for temperate species that normally live in North America or Europe.
• Make sure you know what your snake eats in the wild. Trying to feed a mouse to a snake that only eats eggs will not be successful. Do not buy snakes for which you can’t easily obtain prey items.
• Try another species of prey. If your snake won’t eat mice, try a hamster or if your snake won’t eat a goldfish, try a minnow.
• Make sure that the size of prey is appropriate for your size snake. A good rule of thumb is that the head of the prey animal should be no larger than 3/4 the diameter and no smaller than 1/4 the diameter of the snake’s head.
• Offer food during the time of day that the snake would be hunting in the wild. Offer it when there are few or no people around.
• Never introduce a fully functional prey animal to an anorexic snake without direct supervision. When the snake is not interested in eating the rodent, there are countless cases where rodents have attacked the snake. Many snakes have been seriously injured or killed by rodents that were supposed to be their prey.
• Your snake will not eat if it is not well hydrated, so make sure that the water dish is large enough for him to soak in. Keep the water fresh and clean.

Prevention

The best prevention is to buy healthy captive bred snakes that are readily feeding on their own on easy-to-obtain prey items. At home excellent husbandry will prevent most snakes from becoming anorexic.

Avoid handling snakes for at least 48 hours after a meal. Have your veterinarian test a stool sample from your snake for the most common parasites found in that species. Follow your veterinarian’s instructions for administering de-wormers. In addition, make sure you clean and disinfect your snake’s cage and cage furniture after all de-wormer doses. This will minimize your snake’s chances of re-infecting itself from immature parasites or parasite eggs that may be in the cage.

Although adverse environmental conditions such as cold temperatures, very hot temperatures, drought, poor prey abundance, and flooding may force some species of wild snakes to fast for several months, these conditions usually are not the case for captive animals. In addition, wild snakes usually do not enter a fast suddenly; there is usually a gradual period of cooling or reduction in prey numbers that precedes the fast. During this period, the snake’s body has time to adapt to the fasting state.

When enduring a forced fast, snakes reduce their activity levels and the basic rate at which their body burns calories. They slow down their metabolism until the environment is favorable to them successfully hunting again. Herpetologists that hibernate their snakes have recognized the need for slow transitions for years. If snakes are not given the time to pass the feces of their last meal prior to a serious drop in temperature, the food left in the gut will rot and make the snake sick. In general, except for hibernation, snakes in captivity are not given the environmental cues necessary for them to successfully fast for long periods of time.

If you have acquired a snake that is not eating and someone tells you that this is normal, be careful. Unless the snake is purposefully being manipulated by cooling or change in water availability or just getting ready to shed, the anorexia is probably abnormal.

Neonatal snakes do not usually feed until after their first shed approximately two weeks after hatching. Until this time, they live off of the remnants of their yolk sac.

Causes

Although many cases of anorexia are secondary to poor husbandry, the following is a list of common medical problems that are associated with anorexia in snakes:

• Mouth infection (infectious stomatitis, mouth rot)
• Pneumonia
• Intestinal parasite infection
• Kidney disease
• Liver disease
• Inclusion body disease of boids
• Systemic or intestinal bacteria infection
• Retained eggs
• Intestinal impaction

It is important to determine that a snake is really anorexic. Many snakes are overfed in captivity and simply cannot eat as frequently as their owner wishes to feed them. An excellent diet history and a normal physical examination with the exception of obesity is usually diagnostic for this condition. A conclusive diagnosis is made when the snake’s appetite returns after a decrease in portion size and an increase in feeding intervals is instituted.

Diagnosis

• History. A thorough husbandry history for an anorexic snakes usually includes questions about cage temperature and how it is measured, presence of a temperature gradient, types of heating and light elements, light cycle, presence and type of hide boxes, access to water, selection of prey item (species, live or killed, color, size, temperature if thawed), presence of cage mates, last breeding date, and usual time of feeding. Your veterinarian will also want to know if your snake has ever eaten for you or a previous owner, has ever been attacked by a prey animal, normal time between sheds and stools, any recent changes in these, and the time of the next expected shed.
• Hematology. An analysis of red and white blood cells will allow your veterinarian to determine if anemia, blood parasites, or an overwhelming infection is the underlying cause of anorexia.
• Serum chemistries. This blood test that evaluates organ function and electrolyte levels can be used to look for underlying kidney or liver disease. In addition, serum chemistries can be used to diagnose mineral or electrolyte imbalances such as hypocalcemia (low blood calcium), hypokalemia (low blood potassium), or hyperkalemia (high blood potassium). In addition to the chemistry values mentioned above, values for glucose (blood sugar), cholesterol, total protein, and bicarbonate (helps to regulate the blood pH) can help your veterinarian give you a prognosis for your snake’s recovery.
• X-rays or ultrasound. These tests can be used to determine if your snake is not eating due to an obstruction. Many, but not all snakes also regurgitate (throw up) if they have an obstruction.
• Cytology. Specialized fecal tests and cultures are important to determine the actual cause of any thickening or infection. A specific cause will allow your veterinarian to select the best treatment plan and also give you an estimation of your snake’s chances of getting better.

Treatment

• Tube feedings. If your snake hasn’t eaten in a very long time the stomach and intestines atrophy (shrink) to the point where the snake can’t digest a whole animal anymore, even if he feels like eating. Depending on the state of atrophy, your veterinarian may start off with a dilute electrolyte and sugar solution similar to solutions used to rehydrate babies. Do NOT use milk formulas for babies or senior citizens. Since snakes cannot digest milk, these will cause diarrhea. Later sugar and electrolyte powders can be added to increase its osmolality (density).
• Surgery or endoscopy. If your snake has an obstruction due to a foreign body, there is a good chance that your veterinarian will need to either perform surgery or endoscopy to remove the blockage. In some cases where snakes have swallowed lots of small pieces of bedding (such as gravel), oral fluids and lubricants administered along with lubricating enemas can sometimes relieve the impaction. These procedures must be performed very carefully in order to avoid worsening the obstruction, causing aspiration pneumonia or rupturing the gastrointestinal tract.
• Drug therapy. If your snake has an obstruction due to compression or a thickening of the intestinal wall, your veterinarian will need to ascertain the specific cause of the swelling. If the cause is diffuse and due to an infectious agent, your veterinarian will likely treat your snake with systemic drugs. If the thickening is localized your veterinarian may need to perform surgery in addition to administering systemic medications.

Home Care In-depth

Unless you only use your heating devices during the day, make sure that they are not giving off visible light. Many people use regular light bulbs to heat cages. When they are left on 24 hours day, they can interfere with the snake’s circadian (daily) rhythms. Once the cycle is disturbed, many reptiles stop eating. Use of ceramic or infrared bulbs circumvents this problem. For snakes that use hide boxes or burrow, an under-cage heating pad can provide temperature gradients without excess light.

If your snake’s cage is located in a high traffic room, consider getting a cage cover, it can help maintain the normal light cycle and give your snake extra seclusion when its time to rest. If your snake still won’t eat, it may be necessary to move it to a quieter location.

The following tricks can be used to stimulate a feeding response in some snakes.

• Make sure that you are using fresh prey animals. Even frozen prey will get freezer burn after several months.
• Keep all frozen food tightly sealed until just prior to use. Try to prevent frozen food from picking up odors from other items kept in the freezer.
• When defrosting frozen prey, place the prey in a sealed plastic bag. This will prevent the surface from changing texture (a desert snake may not like to eat a wet rodent) and picking up flavors that may be in the soak water.
• Place the sealed bag in warm water to thaw the food.
• Use a thermometer to measure the temperature of the prey item (place in mouth and down esophagus or into rectum). It should match the live animal’s typical temperature.
• Especially for young snakes, splitting the head open to reveal the brains or the chest to reveal the heart can sometimes stimulate feeding.

It is always best to feed the appropriate prey species to snakes, but should you temporarily run out of feeder snakes, lizards or amphibians you can try the following: Save shed skins from usual prey animals. Stuff small rodents into the shed skins before feeding. Rub the shed skins on feeder rodents. Some people collect the slime from amphibian and fish skin and freeze it in a jar. As needed they thaw a little bit and rub it on the head of alternative prey items.

• For cavity feeders (ball pythons), introduce stunned or thawed prey item into hide box. Offer the snake several choices of hide boxes.
• Snakes that have been previously attacked by a particular prey item often develop an aversion (fear, distaste) for that same type of prey animal. In these cases switching from mice to young rats or gerbils or hamsters can be helpful (or visa versa). Sometimes just changing the color of fur will be enough to entice the snake to eat.
• If you are not familiar with the natural history of your snake and you have been trying to feed it rodents while waiting for your books to come in at the library, try feeding a small lizard.
• If your snake has cage mates, try feeding him separately.

Prevention

Optimal treatment for snakes with anorexia requires a combination of home and professional veterinary care. Follow-up can be critical.

Administer any prescribed medications or food supplements as directed by your veterinarian.

Be certain to alert your veterinarian if you experience any problems while treating your pet. Be especially careful to report regurgitation, decreases in activity or the development of diarrhea.