Breeding Trans-Pecos rat snakes (Bogertophis subocularis) starts with proper care and feeding. Before breeding this beautiful species, ensure your snakes are properly housed, fed, and identified, and confirm you have an accurately sexed male and female.
Choosing the Right Trans-Pecos Rat Snakes For Your Breeding Project: Trans-Pecos rat snakes can be challenging for inexperienced snakekeepers to sex. This article does not detail gender determination methods, as some are invasive or require experience. For reliable procedures, consult rat snake books, reptile magazines, peer-reviewed Internet forums, veteran breeders, and veterinarians. Maturity and size vary among rat snake species, but Trans-Pecos rat snakes are generally sexually mature when exceeding 36 inches in length. Males as small as 30 inches and 225 grams can sire viable embryos, but females under 250 grams seldom accept male advances. Avoid breeding females below 300 grams to prevent egg-laying difficulties and potential death. Age affects maturity less than size; with weekly feedings, sexual maturity is usually achieved in 2 to 3 years, depending on cage conditions, genetics, and feeding regimens. The Right Breeding Enclosure For Your Trans-Pecos Rat Snakes: Appropriate caging and good maintenance are essential for reproduction. Trans-Pecos rat snakes require slightly different cage conditions than most North American rat snakes, so some maintenance tips are included here. (For more on captive care, refer to the April 2013 issue of REPTILES magazine.) General maintenance for Trans-Pecos rat snakes differs from most North American species, but do not assume their cage should emulate the harsh, arid climate of their native Southwestern U.S. and Mexican deserts. At night, when snakes are active, conditions are not as extreme. Given their nocturnal habits, they need shelter from daytime heat and light, often hiding in underground or cave settings where it’s cooler and less arid. Crucial for captive success is offering maximum ventilation achievable.For most glass aquariums, nylon or wire mesh lids provide the primary ventilation. Since maintaining proper cage temperatures and ambient humidity is difficult with screen-sided enclosures, glass aquariums with full screen tops are recommended. While cross ventilation from opposing walls would be more efficient, snakes can injure their rostrums by trying to escape through side mesh panels. Do not restrict ventilation through the screen top; Trans-Pecos rat snakes do poorly in overly humid environments. If your room has high ambient humidity, use a particulate wood pulp substrate like Aspen bedding to wick moisture away from the cage air. If your snake shows feeding, digestion, or breathing issues—such as mouth gaping—excessive cage humidity may be the cause.
Ideal cage temperatures for Trans-Pecos rat snakes range from 82 to 85°F on the warm side to the low 70s to 81°F on the cool side. This is typically achieved by heating one end with an undertank device and leaving the other end unheated. Provide two or three hides that are only slightly larger than the snake, as most snakes avoid cavernous hides. Snakes use properly tempered zones mainly if they offer hiding spots. Nocturnal species like the Trans-Pecos rat snake lack eyelids and instinctively avoid open areas to prevent eye damage from ultraviolet light and to evade detection by predators or prey. It is a myth that North American rat snakes will burn themselves on hot glass beneath the substrate; adequate hides and proper temperatures reduce burrowing. However, prolonged contact with hot surfaces can deplete sperm stores in males. If your snake burrows, it may be due to insufficient heat at the substrate surface or excessive substrate depth. Burrowing is not natural for Trans-Pecos rat snakes, as shown by their head shape, and occurs only if cage needs are unmet. Trans-Pecos Rat Snake Shedding The shedding process lasts eight to 10 days. During this time, you can safely increase ambient humidity by slightly dampening the substrate around the warm hide daily, but avoid over-dampening to prevent fungal or bacterial growth.Slightly dampening a small zone of the substrate rarely causes unsafe cage humidity. During shedding, moderate dampening near the warm hide helps rat snakes stay hydrated when they avoid leaving their hide for water. It is acceptable to mimic natural semi-humid hides year-round, but do not let damp substrate areas stay moist for entire days. Undertank heating is recommended, as most over-tank heaters can dehydrate the cage air. Moderation leads to better cage conditions.
Water bowl diameters should be small. Some breeders provide water for only 24 hours, once or twice weekly. Change bedding substrate partially or fully if water spills or feces are found. Aspen bedding is ideal and non-toxic due to its natural desiccating properties. Natural wood products are both aesthetic and functional. Preparing Your Rat Snake For Brumation: Allow 10 to 14 days before brumation for snakes to evacuate their digestive system. Gradual temperature transitions are unnecessary; rat snakes adapt quickly to extremes, as seen in wild examples. They can adjust to temperature changes in hours, even in snowy montane areas. Brumation is similar to mammalian hibernation. Captive rat snakes breed more reliably with emulated seasonal changes, favoring summer months for fertile reproduction. While artificial seasons can stimulate breeding, using natural winter coolness from parts of your home (like cooler areas) helps achieve safe brumation with minimal artificial resources. Brumation is not mandatory but improves reproduction success. Ideal brumation for adult rat snakes involves cooling at 45 to 65 degrees for 60 days before reproduction. Duration can vary from 45 to 80 days based on temperature, but avoid above 70 degrees (risk of illness) or below 35 degrees for over a day or two (potentially lethal).Most snakes can be safely brumated in containers smaller than their regular enclosures, provided there is adequate ventilation. Monitor brumation conditions weekly to ensure proper temperatures and dry substrate. Change drinking water regularly if it becomes soiled by substrate, shed skin, or feces.
When using screen tops for brumation, be cautious: snakes may push against the screen to seek warmth or avoid high humidity, potentially injuring their rostrums. Opt for containers with evenly spaced holes that have smooth edges. Holes made with a pointed soldering tool are safer than drilled or reamed holes. I recommend offering a small water bowl only once or twice weekly for 24 hours during brumation. Through high-ventilation brumation practices, my Trans-Pecos rat snakes have survived without casualties, even after an unexpected temperature drop to 30 degrees. Success is attributed to avoiding high ambient humidity. Many rat snakes can breed without brumation. If you cannot maintain temperatures below 70 degrees, avoid brumating them. If snakes burn excessive calories without replenishing (e.g., due to fasting from low body temperatures and reduced metabolism), their immune systems may weaken, leading to illness or death. Emerge From Brumation Resume normal feeding schedules after brumation ends. No gradual warming is needed post-brumation, just as cooling isn’t required beforehand. If not shedding, feed Trans-Pecos rat snakes within three to seven days of emergence. The first two meals should be smaller than usual. Then, provide rodents sized appropriately for their body. An accelerated feeding regimen (e.g., two rodents per week instead of one) helps rebuild fat stores lost during brumation. Males fatten quickly even with less food, so increased feeding mainly benefits females needing extra fat for egg production. Shedding in adult rat snakes post-brumation often signals reproduction. Most Trans-Pecos rat snakes shed after three to seven weeks of steady feeding at 80–85 degrees. This first shed, called the post-brumal shed, typically indicates female ovulation or its onset. While not a sole cue for breeding, introduce the male after the female’s post-brumal shed to maximize annual breeding chances, as individual snakes vary.While not all sheds alert us to reproduction stages, after brumation, most sheds certainly do. More than 80 percent of all females that have been maintained via emulation of natural annual seasons will be in some stage of egg production after the first post-brumal shed. If ovulation has not occurred by the second post-brumal shed, it should occur in the following weeks, but almost certainly by the time of the third post-brumal shed.
There are underlying stimuli that dictate the processional timing of, and/or failure of, reproductive processes, but most are related to improper temperatures and off-seasonal event timing. Therefore, it is wise to introduce the pair of adults immediately after each shed in the spring and summer seasons, just in case the female is on an atypical reproductive schedule. Introducing Rat Snakes For Breeding When introducing snakes to breed, the male may be introduced to the female’s cage or vice-versa. I have not observed notable breeding advantages regarding introducing the female to the male’s cage versus the male to the female’s cage. Generally speaking, it is wise not to feed either snake within hours prior to a breeding introduction for at least two good reasons: fear of mistaken identity (are you introducing my mate or feeding me?), and in rare instances, regurgitation from proximity stress or excess motion during breeding. If you do not need the male to breed a second female, communal housing is relatively safe. Trans-Pecos rat snakes are not known for cannibalism within their species, but in rare situations, the male could fail to retract one of his hemipenes (plural for the paired penises of a male snake) after copulation. If communally housed, you would likely not react to such a potentially catastrophic malfunction in time to correct it. Historically, I put the odds of this happening at one in every 100 breeding cases, but of course, that’s only based on the way I maintain my snakes during breeding seasons. One of the most common reasons for failure to retract a hemipenis (one of the paired penises of a male snake) after mating is from particulate substrate material irritating and therefore preventing painless retraction. Should this happen, the result is often the loss of that hemipenis. Hence, you may want to introduce the breeding pair to a bare cage floor or a layer of newsprint on the cage floor. It is not uncommon for a male to be incapable of safely breeding for up to two years after such a tragedy. We therefore recommend conjugal management by monitoring each breeding event, to ensure that there are no such problems. If you do need the male to breed other females, there is another reason it is recommended that you do not let them remain together in the cage indefinitely. Mature rat snakes can copulate up to five times in a 24-hour period, so after several days the male’s sperm stores could be seriously depleted. Observation by humans is tolerated by most mating snakes, but you should keep distractions to a minimum.Most receptive pairs will copulate within minutes to one hour after introduction, but Trans-Pecos rat snakes often take longer. When mating occurs, it typically lasts 30-60 minutes. If no riding or parallel positioning happens after one hour, separate the pair and retry after several days. When females emit pheromones indicating receptivity, males usually court successfully within minutes by subduing the female and positioning atop her body.
After 1-3 copulations over seven days, females typically show increased appetite. While reduced appetite before egg-laying is rare, don’t be alarmed if it occurs even with optimal cage conditions. The goal is increased calorie consumption during this breeding phase, but fasting doesn’t necessarily prevent fertile reproduction. The female’s post-brumal shed indicates egg-laying preparation, though copulation doesn’t guarantee fertile eggs. Natural breeding schedules and optimal conditions don’t ensure reproductive success. Re-introduce the male after the second post-brumal shed. If she mates within one hour, this isn’t her pre-partum shed. If she rejects the male for 60 minutes, egg-laying will likely occur within days. After pre-partum shed, she’ll lose appetite and must not be fed to avoid egg impaction and potential death. Prepare two plastic containers when certain of pre-partum shed: a nest box with damp sphagnum moss for egg-laying, and an incubation container with slightly damp vermiculite/perlite. Prepare these in advance to monitor crucial temperature and humidity conditions for successful oviposition and incubation. The nest box should measure 9-14 inches long, 6-10 inches wide, and at least 6 inches high. Fill half with damp sphagnum moss and secure with a tight-fitting lid. Create an entrance hole twice the snake’s diameter in the lid or sides. Place the nest box inside her cage with fresh drinking water in a bowl too small for egg deposition. She’ll inspect the box for several days but remain outside until 1-2 days before oviposition.Check the moss every few days to ensure it is slightly damp and accommodating for the eggs. When in doubt, slightly dry nest medium is better than overly damp medium.
Prepare the egg incubation container several days before oviposition to evaluate the moisture content of the hatch medium (recommended: water, vermiculite, and/or perlite). I recommend no ventilation holes, as over-hydration is more deadly than slightly dry substrates. Place the box in the intended incubation area (recommended temperature: 78–85 degrees) to stabilize temperature and assess substrate moisture. After 24 hours, small condensation spots on the container’s sides or ceiling indicate proper humidity. If over 60% of the sides or lid show condensation, ambient humidity may be too high. Condensation forms when the container interior is warmer than the outside air, creating moisture droplets. If the box matched room temperature, no condensation would occur, but since rooms are usually cooler, use condensation as a guide for proper substrate hydration. During egg laying, provide the female with maximum privacy. Oviposition can take from a few hours to a full day. If eggs are positioned together, leave them as is. If separated, place them anywhere atop the substrate, nestling them partially but not fully covering them. Instead, cover the entire clutch with damp sphagnum moss. Avoid overly damp moss, as it can clog eggshell pores and smother embryos. Under proper conditions, hatching typically occurs 65–80 days after oviposition, but it may happen in under 65 days with lower temperatures or up to 90 days if temperatures exceed 85 degrees. Eggs incubated above 90 degrees often hatch but may result in problems like poor human tolerance, small size, deformities, feeding issues, or color/pattern anomalies. At lower temperatures (below 80 degrees), hatching can take 85–95 days, potentially causing similar issues but often producing larger hatchlings with better appetites.Incubate snake eggs between 75 and 85 degrees Fahrenheit for robust neonates. Check eggs weekly to monitor humidity and temperature. Open the incubation container weekly or bi-weekly for one minute while fanning to refresh the air.
At an average incubation temperature of 82 degrees (with rare, brief drops below 79 degrees), eggs typically hatch in about 85 days, plus or minus a few days. Note that genetic factors and incubation conditions can alter these timelines. After hatching, neonates will shed within 7 to 13 days, depending on cage temperature and humidity. You can begin offering food after this shed. Under standard cage conditions, 50-70% of hatchlings will eat unaltered frozen/thawed pinky mice on the first attempt, with an additional 15-20% eating within the next 2-3 offerings. Hatchlings that do not eat within 4-6 weeks usually perish or sustain irreversible deformities and digestive damage. Cage conditions and maintenance are the same for both neonates and adult snakes.