Snakes produce offspring in 2 basic ways: The first involves development of the fertilized eggs within the body of the female. When the embryos are fully developed, the offspring are born, appearing like miniature adults. Boa constrictors, water and garter snakes, and rattlesnakes are live bearing species and are considered ovoviviparous. The second method involves deposition of oblong, leathery-shelled eggs within the environment, where the eggs incubate. At the completion of embryonic development, the eggs hatch, producing miniature adults. Pythons and rat and mild snakes are egg layers, and are considered oviparous. In either case, the newborn or newly hatched can fend for themselves and receive no parental nurturing.
Many snake species readily mate in captivity: One mating may result in up to 3 clutches of eggs or 3 "litters" of live young. This is because sperm can be stored within the reproductive tract of the female after insemination. The proper pairing of snakes according to age and sex is essential if reproduction in captivity is to be successful. Sexing of snakes can be difficult because males generally resemble females. Male pythons and boa constrictors have a spur on each side of the vent. Some females have spurs but they are usually smaller than those of males. These observations can be misleading at times. Snakes under 18 inches long can usually be sexed by exerting pressure on the tissues surrounding the vent. Male snakes have paired hemipenes (elongated, spurred structures used during copulation) that can be extruded with this maneuver. The widely accepted method for sexing most snakes over 18 inches in length requires specialized sexing probes. These elongated, blunt-tipped instruments are gently inserted into the vent and directed toward the tail. The probe penetrates only a short distance in females and a much longer distance in males. Only experienced handlers should attempt this procedure.
Artificial Incubation of Snake Eggs: Artificial incubation of fertile snake eggs is quite easy. A small amount of water is added to an empty Styrofoam picnic chest. Then, a thick layer of peat moss, sphagnum moss, vermiculite, shredded newspaper or paper towels is added. The eggs are carefully introduced into this medium. Slightly moistening the incubation material also helps prevent the eggs' drying out. Too much moisture, however, promotes formation of mold, which will destroy the eggs' contents. The relative humidity required to incubate snake eggs falls within the range of 75-85%. The covered Styrofoam chest is then placed on a heating pad, which is set on its lowest heat setting. The ideal temperature range for most incubation lies between 78 to 84° F. The average incubation period for most snakes ranges between 55 and 60 days.