An essential first step to breeding Pantherophis guttatus (formerly classified as Elaphe guttata) is to learn to properly sex your corn snakes. Always check immediately after acquiring them to avoid raising a same-sex pair for years. Probing for hemipenes is the preferred method, and popping (manually everting the hemipenes) works well on juveniles.
Most herpetoculturists practice environmentally conditioning breeder-sized corn snakes (typically those about three feet long). Temperature and photoperiod are both important reproduction triggers. Let corns experience a cooler period coinciding with shorter winter day lengths. This period doesn’t need to be exact, just noticeably lower so the snakes’ reproductive systems recognize it’s time. Internal formation of sex cells requires this cooler rest. Aim for a cool season of 45-65°F for 60-75 days. It doesn’t require critical monitoring; generally cooler and darker conditions suffice. Consistently higher temperatures can cause fat reserve loss, leading to thinner, weaker snakes in spring. Temperatures in the 50s are ideal if maintainable. Minimally disturb snakes during the 2-2.5 month cool period except for cleaning. Keep corn snakes in a completely darkened room during the cool period. Use a timer to provide 9-10 hours of light daily when starting spring, increasing duration by 15-30 minutes every two weeks over subsequent months. Simulate spring’s arrival simultaneously for all snakes to synchronize hormone cycles. This ensures males’ and females’ reproductive physiologies are primed together. Post-hibernation shedding, typically several weeks after warm-up, signals the active breeding season. Experience helps recognize female ovulation signs—mainly bulging posterior halves that feel lateral, soft, and squishy. When females are ready, males will be too. Misting the enclosure with room-temperature water raises humidity, enhancing pheromone spread and recognition.The male will usually take an immediate interest in any new snake in his territory. If a female is detected, he then tries to line up their bodies. When the cloacal openings of the snakes are lined up facing one another, a sudden pulse pushes one hemipenis into the female. The tails typically rise slowly upward, partly intertwined and almost side-by-side after 5 or 10 seconds. The pair stays locked in this position for 10 to 20 minutes on average.
Gravid females usually continue to feed ravenously for an additional three to five weeks after mating before the enlarging eggs in their oviducts make passing food or fecal matter uncomfortable. Their appetites will slacken or quit completely as the females approach their prenatal shed. Note that males will often refuse most, or all, food during the breeding season. Continue to offer food once per week, but don’t be concerned unless your male becomes thin or looks unhealthy. In that case, remove him from the room housing females and lengthen his photoperiod to let him know that breeding season is over. Just before the prenatal shed (the one just prior to laying eggs, typically four to six weeks after mating) is the time to prepare a nesting container for the female. Gravid corns seek out a secret, sheltered place with high humidity to deposit a clutch of eggs. Translucent plastic food storage tubs with snap-on lids have proven to be ideally suited for our nest box needs. A single round entrance hole about twice the female’s widest diameter is cut in the top of a box that has the capacity to hold at least two snakes the size of your female. Female corns like to burrow into the nesting box substrate and shove it aside to form a nesting cavity. Sphagnum moss makes an excellent substrate. Moist vermiculite or crumpled paper towels are fine, too. Place the nest box in the cage when you first notice the female’s eyes clouding. She may find it convenient to rest in a moist alcove to hasten loosening her old skin before the prenatal shed. Corns generally lay their eggs 30 to 45 days after mating. This is usually one to two weeks after their prenatal sheds. They may lay the clutch any time of night or day, and the process may span from an hour or two to a couple days in abnormal cases. As soon as we notice she has laid the clutch, I take the egg mass away. If she’s extremely thin, I offer her one or two fuzzy mice, smaller than her own diameter, right away as a tiny boost before her eyes go opaque again. Some females will accept such snacks immediately; others refuse them. The average number of eggs per clutch ranges between 10 and 30 eggs. Young or undersized specimens tend to lay low numbers of physically large eggs. Good eggs are quite hardy, and will usually hatch, even if some in the clutch die and rot while clinging to the good ones. My favorite incubation media are sphagnum moss or coarse vermiculite. If the material is damp, but not wet enough to drip water when squeezed, and is non toxic, it should work to incubate corn snake eggs.Incubating corn snake eggs requires careful attention to temperature and humidity. The ideal temperature range for incubation is in the lower to mid-80s Fahrenheit, as this produces more robust hatchlings. The upper limit should not exceed 90 degrees Fahrenheit to avoid increasing the risk of birth defects and mortality.
Monitoring egg condition is crucial. It is normal for eggs to dent inward several days before hatching. However, if denting occurs much earlier, this indicates the eggs are too dry. Conversely, the formation of mold or fungus on the eggs or substrate signals excessive moisture, and the eggs will need to be aired out. A good rule of thumb is that ‘Good eggs don’t go bad’; meaning if temperature and humidity are approximately correct, the eggs will hatch successfully. With the vast array of online and offline resources available, your journey into the expanding universe of corn snake morphs promises to be a colorful and exciting experience.