When in good health, mountain kingsnakes do not have to be persuaded to mate. Copulation almost inevitably occurs when introducing pairs in the spring. But copulation does not necessarily mean that breeding has been successful. Both males and females need to have been cycled prior to copulation. A winter cooling period, known as brumation, achieves this better than any other enviromental stimuli (i.e. photoperiod). In fact, without a brumation period, attempts at breeding usually fail. Brumation allows males and females to synchronize their reproductive cycles: spermatogenesis and vitellogenesis. Apparently, the cooler temperatures allow for sperm maturation in males.

A successful brumation lasts at least three (3) months. But experience has shown that brumation periods can last up to five (5) months with mountain kingsnakes. Temperataures which suffice for many other colubrids, 55 F to 60 F, will not work for mountain kingsnakes. Ideally, a set temperature of 50 F will work across the board for all species of mountain kingsnake. Better to error on the cooler side; most individuals do fine at temperatures of 47.5 F and slightly lower, but if temperatures stay above 55 F, males may not "produce" enough sperm during the spring.

The kingsnakes should be given at least two (2) weeks of warmer temperatures after their last meal to properly digest and clean out their gastrointestinal system. After the two weeks, temperatures can be dropped gradually over the period of another week until the desired brumation temperature has been reached. Kingsnakes should be maintained individually with access to water during this period. Other than routine checks, disturbances should be kept to a minimum. Snakes that exhibit signs of respiratory disease during brumation should be warmed back up and given proper medical attention.

Plot of Temperature vs. Time. This plot shows the author's regimen for brumating mountain kingsnakes. In the early and latter parts of brumation, temperatures hover around 50 F. During the longer, middle period, temperatures drop to around 47.5 F.
Plot of Temperatures vs. Time

After pulling the adult breeders out of brumation, they should be given one (1) to two (2) weeks time to warm up before their first meal. Males should not be subjected to too high of temperatures as some hobbyists believe that higher temperatures may decrease sperm motility. Typically, females should be fed heavily in preparation for egg production. At this time, a little calcium supplement would not hurt, though most females seem to do fine without it. Males should only feed twice or thrice initially before trying pair up animals; overweight and recently "gorged" males may feel uninclined to breed. Within four (4) to five (5) weeks after emerging, the females should turn opaque, signaling that their first shed of the season will quickly follow. Once ecdysis occurs, the males can then be introduced with the females ( Note: in regards to pyromelana, males of this species seem to exhibit greater interest in breeding prior to the female's first ecdysis; after this time the males may lose interest in breeding.) For the following two (2) to three (3) weeks, the pairs can be separated and reintroduced (providing this does not stress the females). Multiple copulations with a potent male help ensure that a female will lay fertile eggs.

Several weeks after copulations have ceased, gravid females will begin to show signs of eggs. Not much later, the female will turn opaque--signs of the telltale "pre egg-laying" shed. After shedding, a nest box containing moist sphagnum or vermiculite should be placed with the female. Once the female has dropped the clutch, usually containing anywhere from one (1) to ten (10) eggs, the eggs should be incubated between 82 F to 84 F. Smith reports that at 82.5 F, eggs routinely hatch after 55 to 65 days (1998). Females should again receive adequate food to replenish their stores.

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