Vipers: A Guide for the Advanced Hobbyist

Vipers are snakes distinguished by their large, movable fangs, and many different species are found throughout the world. Here is expert guidance on care, housing, and breeding of this often dangerous group of snakes. Heavily illustrated with vivid color photos and instructive line art, this book was written by one of America's leading experts on reptiles and their care. DOWNLOAD HERE

Vomiting and Regurgitation

Another common reason that snakes are brought to veterinarians for exams is that they are regurgitating or vomiting. Regurgitation occurs soon after eating, whereas vomiting occurs hours or days after ingestion of food. Regurgitated food is generally undigested food expelled primarily from the esophagus (passively, that is, without much force). Uomitus consists of partially digested food, usually actively expelled from the stomach. With reptiles, distinguishing between the two actions can sometimes be difficult. The point is that the snake is not holding down food, and possible causes are numerous.

There are ten common causes for vomiting or regurgitation in snakes, but remember that there may be more than one cause for any particular case. A good example of this has been termed "regurgitation syndrome" by Ross and Marzec (1990) which occurs in all snakes, although Ross and Marzec were studying boid snakes at the time the phrase was coined. Following are the ten common causes for vomiting or regurgitation in snakes:

1. Handling too much or too soon after feeding
2. A sharp (sudden) drop or rise in ambient temperature or just improper ambient temperature for digestion
3. Increased stress (including from mating) soon after feeding
4. A meal that is too large, too old, or too toxic or offered too frequently
5. Bacterial infection
6. Protozoal infection (amoeba, coccidian, flagellate)
7. Metazoan (worm) infection
8. Tumor
9. Excessive drinking right after eating 
10. Dehydration

Sometimes, making minor changes to a snake's environment or adding a new animal to the enclosure may be very stressful for the snake and cause it to vomit its last meal. Perhaps the most common cause of vomiting or regurgitation is an ambient temperature that does not allow normal digestion. More frequently, a drop in ambient temperature is the cause of sudden onsets of vomiting or regurgitation, yet it also can be caused by sharp rises in temperature. This symptom should serve as a warning to the herpetoculturist that the normal ambient temperature may be marginal for digestion.

Very large meals may cause irritation of the gastrointestinal tract and may result in vomiting or regurgitation. Toofrequent feedings have the same effect. In snakes, irritation leading to vomiting or regurgitation may also be the result of swallowing a large meal backward; the scales of a fish or the fur of a mammal—which generally are directed from nose to tail—would be pushed up if the prey were swallowed tail end first and would irritate the snake's insides.

If the prey offered has been in freezer storage for a long time, perhaps longer than six months, it may be loaded with bacteria or bacterial toxins, which in some cases may induce vomiting or regurgitation as happens with humans in cases of food poisoning. Some food items, such as certain species of frogs and toads, produce chemical toxins that may be a little more than some snakes can handle.

Bacteria flourish in a filthy environment. Bacteria that are extremely contagious are commonly discovered as the cause of outbreaks of vomiting. These bacteria may be responsible for an inflammation of the lining of the stomach and intestine known as bacterial gastroenteritis. Not surprisingly, two of the contagious gram-negative bacteria, Salmonella and Arizona, are frequent offenders. These bacterial infections are among the few cases in snake medicine in which oral antibiotics are deemed appropriate and necessary. Ross and Marzec (1984) and Ross and Maxzec (1990) have used ciprofloxacin and amoxicillin successfully. The senior author of this book commonly uses ciprofloxacin and enrofloxacin orally in snakes with gastroenteritis, at the doses listed in the drug tables at the back of the book, and it has worked very well.

Since we discuss parasites (protozoan and metazoan) in some detail in the last chapter, we will not dwell upon them here. However, you should always consult your veterinarian if you suspect parasites. It is usually a waste of time and money—not to mention dangerous for the snake—to pump one routine deworming agent after another into a debilitated snake without the benefit of repeated fecal exams or a gastric wash.

A foreign-body obstruction commonly occurs in captive snakes that are housed on the improper substrate. Check your references, and use the proper substrates as mentioned in chapter 2. Towels, hand cloths, and T-shirts are not acceptable; they may be accidentally ingested. Incidentally, you can sometimes induce the vomiting of an ingested towel or hand cloth by lowering the cage temperature. Give the snake a sterile electrolyte solution intraperitoneally to counteract the dehydrating action of the towel. Then place the snake in a relatively cool area, about 50°F to 60°F (10°C to 16°C). Vomiting of these soft objects usually occurs within two to three days under these circumstances. You must monitor the snake for dehydration, and intraperitoneal fluids and antibiotics are advisable during and after this procedure. Note that this is a practical field approach to be used when sedation and endoscopic retrieval of the hand cloth are not possible. This approach is definitely worth considering before attempting surgical retrieval, but you must carefully monitor the state of hydration in these animals. (In a seriously dehydrated snake, its skin has wrinkles that return very slowly or not at all to their original position when gently pulled away from the body)

In older snakes, tumors are definitely a possible cause of regurgitation or vomiting. Your reptileoriented veterinarian can determine if one is present by means of physical examination, endoscopic exam, X ray, or any combination of these.

Many snakes tend to drink heavily after gorging on a large meal. Sometimes, it appears that they may overdrink; vomiting or regurgitation occurs soon afterward.

Dehydration theoretically causes irritation to the lining of the gut by blocking the smooth passage of food because of the increased friction, thereby increasing the likelihood of vomiting or regurgitation.

When vomiting occurs, isolate the animal, restrict handling, lower the temperature of the enclosure as needed, feed less frequently and offer smaller prey, and make sure that the cage is clean and the food is fresh. If vomiting persists, have your snake examined by a reptile-oriented veterinarian, who may suggest a fecal exam, a culture and sensitivity test, or a biopsy to determine the cause or causes of the problem and the proper treatment.

Snake Diseases Constipation

Overfed, underactive snakes are prime candidates for constipation. Some snakes that are fed frozen and thawed food items tend to become dehydrated as a consequence of fluid loss in prey items during the freeze thaw cycle. Other fac-tors that can contribute to constipation are cooler temperatures and lower humidity than the snake is used to. Cooler air temperatures can cause a snake to "hug" its heat source; by doing so, the inactive snake essentially "cooks" the stool in its colon for several days, thereby drying it out and making it more difficult to pass. Lower cage humidity increases the rate of evaporative water loss even more and worsens an already serious situation. Without any intervention, the snake's stools may become as hard as rocks, which is why they are called fecoliths (fecal stones). Chronic constipation (formally, obstipation, noted by hard stools every three to five days) may result in quite a backup, especially as many snakes continue eating even when constipated.

There are a number of treatments for constipation. The first and most important action is to correct the environment. Eliminate drying substrates, such as corncob litter. Wood and cardboard fixtures are also very drying and thus should be removed from the cage. Avoid using cages with sides made of untreated wood as these types may also dry out the air within the cage. Other treatment options to consider include using a humidifier, increasing the size of the cage and providing additional accessories to encourage exercise, or reducing the frequency of feeding or feeding smaller and more digestible items. Renowned reptile veterinarian Steven Divers (pers. comm.) suggests that injecting water into frozen and thawed prey items may be helpful. The next step in treating constipation is to try several warm water soaks. Placing the snake in shallow, warm water for fifteen minutes per day for three or four days will usually cause it to defecate. If not, an enema of warm water or of a very dilute solution of dioctyl sodium sulfosuccinate (DSS) will likely work. Frye (1991) quotes PaulMurphy and colleagues (1987) in advising that DSS be diluted at a ratio of one part DSS (standard stock solution) to 20 parts water if the solution is to be administered through a stomach tube. Frye also advises the use of magnesium oxide (milk of magnesia) suspension or mineral oil in small amounts as aids for constipation. One mL/kg of body weight is a safe dose for milk of magnesia.

A small quantity of mineral oil (1 mL/kg of body weight) administered through a stomach tube has long been recommended and, indeed, does seem to work. However, the administration must be made by someone experienced in tubing reptiles as the improper placement may lead to regurgitation as well as aspiration of the oil and result in pneumonia. One means of administering the mineral oil that we have found successful has been jokingly referred to by the senior author as "mouse lax" or "rat lax:" Basically, if a snake is still feeding, you can offer a prekilled mouse or rat that has been injected with the appropriate dose of mineral oil. Several days later, when the mouse or rat is digested, the oil is released and softens the stool; defecation occurs within several days to a few weeks.

If the above approach proves unsuccessful, surgical removal of the fecoliths is necessary. However, the best approach to this problem is prevention. Avoid overfeeding your snake, provide it with as much room as possible, and maintain appropriate temperature and humidity ranges. Although some sources have suggested that routine handling may be good exercise for the snake, remember that some animals do not tolerate handling very well.