Husbandry of Heterodon nasicus kennerlyi
Housing
Mexican hognose snakes must be kept in suitably sized enclosures. This is important for several reasons. When in an appropriately sized enclosure, the snake tends to eat more readily and consistently, is generally easier to keep clean and sanitary, and offers a sense of security for the snake.
When considering hatchlings, smaller enclosures are better than larger ones. Most keepers tend to make the mistake of using enclosures which are too large for hatchlings. For hatchlings, the ideal size enclosure is 6" X 6". When hatchlings are placed in something larger than this, they tend to become "distracted". They seem to be more interested in checking out their environment, and spend countless hours cruising around their enclosure. Unfortunately this seems to impact the hatchlings' desire to feed. Another draw back is they become hard to find during feeding attempts. In order to offer the hatchlings food, you end up disrupting the snakes by shifting through the enclosure and bedding. Once agitated, the snakes will usually refuse to eat. Once a hatchling starts feeding regularly and starts to increase in size (6 - 12 months of age), it can be moved to a larger enclosure. I recommend an enclosure about 12" X 6".
When specimens reach 2 - 2 ½ years of age, I would recommend putting them in a 14" X 9" enclosure. I keep my males in the 14" X 9" enclosures even when fully grown, but move the females to an enclosure of 20" X 13" when they reach full size (3 - 4 years of age).
A good general guideline for sizing an enclosure to a specimen is as follows. The length of the enclosure should be about equal to the length of the snake. The width of the enclosure should be half its length. The height is the least critical, but should be half of the width. Therefore, a specimen 18 inches long would do best in an enclosure about 18 X 9 X 4 inches in size.
Substrate
There are a lot of options when it comes to choosing reptile substrate. It seems as though each one has its pluses and minuses. Cost, safety, and convenience are some factors we must consider. Hognose snakes will thrive well in any commercial reptile bedding. I use a mixture of recycled paper bedding and aspen wood shavings; in equal volumes.
Avoid coconut husk bedding for hognose snakes, as ingestion can cause complications.
Temperatures and Heating
Mexican hognose snakes do best in typical colubrid temperature conditions. The ideal ambient temperatures range is from 75-80 oF. A basking area with a warmer temperature about 83-85 oF is desirable. Although there are many successful ways to heat a reptile enclosure, I'll describe what has worked for me.
All of my enclosures are the plastic "shoe box" type containers, with holes drilled in one side of the cover for ventilation (see image). I heat all of my enclosures with 11" heat tape (20 watts/foot), which is controlled by a proportional thermostat. The surface temperature of the heat tape, taken with a digital thermometer, is 83.0 ± 2.0 oF. The enclosures are placed on the heat tape so only one half of it gets heated, and the other half remains unheated. The holes in the cover are positioned on the unheated side of the enclosure.
This set-up will give the following temperature zones within the enclosure. The warmest zone in the enclosure is under the substrate on the heated side, and is 80.0 ± 2.0 oF. Generally after eating, the snakes will burrow under the substrate to take advantage of this warm zone immediately over the heat tape. The surface temperature of the substrate on the heated side of the enclosure is about 78.0 ± 2.0 oF. The unheated side of the enclosure ends up being several degrees cooler, and is usually about 73.0 ± 2.0 oF.
One of the most important devices for successful reptile husbandry is the thermometer. Having an accurate thermometer is very important, thus all my thermometers are calibrated to a NIST traceable thermometer every year.
Feeding
We have to consider some important factors in determining what, how much, and how frequently we feed our captive hognose snakes. Although Mexican hognose snakes will readily accept toads, frogs, and lizards in captivity, it is best to feed them appropriately sized frozen thawed rodents. Feeding frozen-thawed rodents is safer, less expensive, and they are much easier to obtain than other food types.1.
Feeding too much or too little can both have unhealthy results in your hognose snake. Temperature, activity, age, breeding, and brumation all play a role in determining this. Although there are specific times to increase and decrease meal frequencies, one appropriately sized rodent every 7-10 days is sufficient for an adult hognose snake. Hatchlings and sub-adults should be fed one appropriately sized rodent every 7 days.
The times during yearly cycling when it is necessary to increase the frequency of feedings is before2 and after brumation, breeding, and oviposition3. At these times, feed adult snakes every 7 days, and allow them to get a little "chunky". Extra fat reserves are useful when the snake may go without eating for long periods of time, or when extra nutrition is needed for developing eggs.
The best method to feed your snake is simply to place the food item on a sheet of aluminum foil or paper; so the substrate does not stick to the food item, and set it in the enclosure. Setting the food item in the enclosure during the evening and leaving it over night is best, as the snake is then completely undisturbed.
Another method is using tweezers or hemostats to offer the snake the food item. This method does work, but is sometimes intimidating to young snakes. Generally, if you offer the snakes the food item this way, and it does not take it immediately (within 1 minute), it usually won't no matter how long you try. Continuing to try will only upset the snake more. When this method does work, the snake will usually seize the food item as soon as it scents it (within 5 seconds).
One important point is not to feed captives any wild caught foods; as they may harbor parasites and diseases you could introduce into your collection.
1It should be mentioned, there is some debate on the health issues of feeding hognose snakes an all-rodent diet. In particular, some think doing so will cause a condition called "fatty liver". Fatty liver is a condition in humans, which is most commonly caused by obesity. Therefore, it would seem more likely, if this condition does occur in captive hognose snakes, that obesity would also be the cause of this condition.
Another concern that has recently surfaced is that hognose snakes are not able to "pass" hair through their digestive tracts. This is thought to interfere with nutrient absorption by collecting in the intestine; ultimately causing death through malnutrition. It should be noted that no documented case of this has been found, nor any long-term breeders of hognose snakes that feel this is a concern. It should also be noted that some specimens are still alive and healthy, at over 11 years of age, and have never been fed anything other than rodents.
2A snake should not be fed at all for three full weeks before brumation.
3A snake should not be fed after the pre-oviposition shed.