In the short span of two decades, breeding snakes in captivity has evolved from hit-or-miss success in a backroom to a mainstream business. And there are some general guidelines for enhancing the reproductive potential of your snakes.
The reproductive cycle, or breeding responses, of many snakes is prompted by the average temperatures they experience and the photoperiod, which is the length of the day versus the length of the night. Snakes typically become sexually active after emerging from winter dormancy (or at least a period of comparative inactivity) as the temperature and photoperiod increases in the spring. So, to breed snakes in captivity you'll have to provide them with some degree of winter cooling and then warm them.
In general, a snake originating from a temperate area (some rat, king and bull snakes, some rosy boas, and Argentine boas, among others) will require more and longer cooling than a species from a tropical area. Strangely, snakes that are themselves captive bred often require less preparation than wild collected examples.
Getting Your Snakes Ready
To prepare tropical (and many temperate) snakes for breeding, it is best to first separate the sexes. (Note, though, that many herpetoculturists suggest leaving boa constrictors together at all times.) You should also stop feeding your snake or snakes two weeks prior to cooling. Then reduce the relative humidity and temperature in the tank.
Daytime temperatures of 78 to 83 degrees Fahrenheit and nighttime temperatures of 69 to 73 are usually adequate. The cool should be maintained for 60 to 90 days, preferably the latter. It is often recommended that males be cooled to slightly lower temperatures than females.
During the cooling, snakes can be provided with a natural photoperiod or kept dark. During hibernation we feel that continued darkness is best. Since their digestive systems will be compromised by the cool temperatures, feed cooled snakes sparingly, and hibernating snakes not at all.
After 60 days of cooling, warm the snakes and provide a natural photoperiod. At this time, a night temperature of 75 to 78 degrees and a day temperature a few degrees warmer is best.
To induce actual hibernation in temperate snakes, follow the same procedure but reduce the temperatures even further – to between 48 and 56 degrees. You'll also have to prepare hibernation quarters. A plastic container about the size of a shoebox will service nicely. Place your snake inside and set the container in a dark, cool, little-used closet, a basement, garage or converted refrigerator.
Hibernating snakes must be roused for a drink of water every 15 days or so. Take the snake out of its box, place it on a shelf in front of you and offer it water. After it drinks, place it back into its hibernation box and return it to its cooled area. If the snake doesn't drink, re-offer it water in a week.
At the end of the cooling period, simply replace your snake (or snakes) – tropical or temperate – in its regular cage and return all parameters to normal. After warming the snake(s) for two or three days, begin feeding them frequent meals of small prey items. After determining that digestion has not been compromised by hibernation or cooling, the size of the prey items can be increased.
Snakes may cease feeding during the breeding season. For this reason, it is imperative that they be at optimum weight when they are cooled for the winter and are fed heavily when warmed in the spring.
After the post-hibernation shed (or before if you choose) put the female in the male's cage. Courtship may begin immediately, but is often delayed until the post-hibernation shedding cycle is completed.
A gentle misting (simulating a rainstorm) may stimulate your snake's reproductive behavior. This can be accomplished with a simple sprayer bottle. Point the bottle upward so the mist falls like a gentle spring rain. Placing a second sexually mature male in the cage may also stimulate breeding, but since the males of some snake species (especially boas and pythons) may fight savagely with a rival male this must be done carefully and under supervision. Be prepared to intervene and remove the second specimen if necessary, but don't get bitten in the process.
Some snakes become particularly aggressive during the breeding season and must be approached very carefully. Caution is particularly important if your snake is large. Be very careful when servicing the cages of breeding snakes.
Not all female snakes breed annually. Some may ovulate biennially or even triennially. This seems especially true of certain of the larger live-bearing boas and vipers. After mating (this may occur several times over a period of days), separate the sexes and feed them heavily.
Gestation and Egg Deposition
Gestating snakes need rather warm, secure areas in which to bask, and ultimately, to deposit their eggs or to give birth. As with all other aspects associated with the keeping of snakes, the size of gestation and deposition sites must be tailored to the needs of your specimens.
An opaque, lidded, plastic dish partially filled with barely moistened peat or sphagnum will often be accepted by your female snake as a deposition site. An appropriately sized access hole should be cut in one corner of the lid. Be careful where in the cage you put the deposition box. If it sets atop an undertank heater, overheating and very rapid drying of the deposition medium may occur. Remoistening the medium regularly may be necessary.
Female snakes look carefully in their cage for the best spot to lay their eggs. The deposition box will probably win, but sometimes a female may decide on her water bowl. To avoid this, be certain that the water bowl is too small for her to coil in or remove the water bowl and provide the female with water for only an hour or so each evening.
After egg deposition many female snakes appear thin and depleted. Offer them small but frequent meals to allow them to quickly regain their lost body weight. Female snakes that retain or quickly regain their body weight following egg deposition may multi-clutch annually.
Correct temperatures for gestation and incubation must be provided. Incorrect incubation procedures can result in embryo deformity or death.
Incubators can be either homemade or purchased. You can make one from a styrofoam cooler, an inexpensive thermostat from a hardware or livestock feed store, a length of heating cable and a few feet of electrical wire. Chick-egg incubators from any feed store may also be used. Be certain that the one you purchase can be adjusted downward to 80 to 86 degrees. Many commercial incubators now have pre-set solid state controls that maintain temperatures far too hot for reptile eggs.
The base temperature during incubations (for most snakes) should be between 80 to 83 degrees. A little variation will not hurt and may actually be desirable. Incubator humidity should be maintained at 80 to 95 percent; we keep an open container of water in the incubator. Keep the incubator dark. Once laid, eggs may be gently moved but should not be turned. Full-term babies will slit the egg with the help of an egg-tooth on their upper lip, and after a variable period of periodically peering from the egg then withdrawing again, they will emerge. Keep the relative humidity high.