Background:
I first want to acknowledge that I am a long time snake keeper, however I have never attempted to breed any snakes. This is due to the fact that until recently I have lived in apartments for the last 20 years and have never had an adequate environment to properly brumate my snakes. Recently I moved into a house with a garage that faces north and thus allows for temperatures to drop in winter months to levels I believed were adequate for brumation. I researched any and every online resource available regarding breeding North American colubrids and specifically the genus Pituophis. I found a lot of information, however some specific details were lacking and in the end I was kind of winging it. My goal was to attempt to breed three pairs of snakes (LA Pine, Black Pine, Florida Pine) recording environmental fluctuations and comparing outcomes between all three species. My plan was to manipulate temperature as little as possible and not to manipulate humidity or photoperiod at all. What follows is my experience with breeding these species of snakes and maybe this information can be useful to others.

Methods:
My goal was to provide the micro-environment that these species of snakes would be subjected to in the wild throughout the year as closely as possible. In the end I used minimal (but safe) temperature manipulation, zero light manipulation and zero humidity manipulation. I recorded daily temperature and humidity fluctuation. Photoperiod was not recorded and was allowed to fluctuate with the outside environment. All three species were subjected to the same environmental ques.

Snakes;
-I won’t go into too much detail here. All 6 snakes are healthy, large and at least 3 years old. None are related to each other. Some are F1 from WC parents. Much hard work was put into acquiring unrelated animals. This was especially true for the LA pines, but this was very important to me.

Set up;
- Location was Nashville Tennessee, Latitude 36.1627° N, 86.7816° W
- Climate of this location is considered humid subtropical
- The snakes are housed in my garage with three windows to the outside. One window with a window unit AC.
- Snakes are housed in standard PVC rack built by myself with Rubber made tubs.
- Pine shavings used as substrate
- All tubs with ample holes for very good ventilation

Temperature;

- June thru October: I did not provide any artificial heat source. My AC unit was set up with a Ranco thermostat and was set to 85 degrees. Most hot summer days the AC would run during the hottest part of the day. Highest temp reached was 88 degrees and lowest temp reached 56 degrees through this time span. Over 95% of the time the temperature fluctuated between 72 degrees and 85 degrees.

- November thru December: In early November I began to provide artificial heat and no longer needed artificial cooling. I unplugged my AC and turned on the under tub heat tape and set it to 85 degrees without any fluctuation. Ambient temperature inside the garage was allowed to fluctuate with the outside environment, although dampened due to being insulated in a garage and not allowed to fluctuate to the extremes of the outside environment. From November thru the end of December the ambient garage temperature fluctuated from a high of 82 to a low of 48 degrees. 95% of the time the temperature fluctuated between 55 degrees and 73 degrees.

- January Thru February: All consistent artificial heat was turned off from December 31st thru March 1st. Ambient garage temperatures fluctuated between a low of 36 degrees and a high of 73 degrees during this time. 95% of the time temperature fluctuated between 43 degrees and 62 degrees. A cold snap in early January brought outside highs in the teens and lows in the single digits. This made me nervous. At this time, the cage temperature was 36 degrees and I decided that I did not want it to fall any lower. I provided a room heater placed close to the rack that kept ambient temps above 38 degrees throughout the following few very cold days. There were two other times that temps fell into the upper 30’s but did not fall any farther There were several warm ups that brought temps into the low 70 ‘s for several days. The high of 73 degrees occurred in February and I resisted the desire to provide external cooling.

- March thru May: Artificial heat in the form of under tub heat tape was restarted on March 1st, was set to 75 degrees and increased in stepwise fashion to 85 degrees by March 15th. I provided under tub heat from March 15th thru May 31st. The heat tape was set to 85 degrees. Ambient garage temps ranged from a low of 44 degrees in March to a high of 85 in May, with 95 % of temps ranging from 54 degrees to 76 degrees.

- In mid May I began to provide artificial cooling with my window AC unit set to 85 degrees.

Humidity;
- I won’t go into as much detail here. Tennessee tends to be humid during every season. I did not do anything to manipulate humidity. I worried that too much humidity during brumation could cause problems. I pondered using a dehumidifier during the winter but decided to do nothing and just let things play out. I did record humidity though. Through all 12 months humidity in the garage ranged from a low 43 % in October to a High of 79% in April. 95% of the time humidity ranged from 48% to 67%. The high humidity mark during brumation was 76% and this was with a temp of 52 degrees.

Feeding schedule; * feeding offered, not necessarily accepted by snake
- June thru September – One small rat per week per snake
- October thru end of November – Two small rats per week for females, one small rat per week for males
- All feeding ceased on December 1 thru March 15th
- March 15th thru pre-egg laying shed – Two small rats per week for females
- March 15th thru present – One small rat per week for males
- Post egg laying to present – Two small rats per week for females

Breeding Schedule;
- Males placed in females cages after female post brumation shed between dates of April 12th thru April 18th.
- Males removed from females cages on May 7st
- My female Florida pine snake never had a post brumation shed. I became inpatient and placed the male in her cage on April 18th. Witnessed copulation occurred within an hour of being placed in her cage.

Results and Observations:

Temperature;
- My approach during the summer months was to cease all artificial heat and use artificial cooling as needed. Results showed a pretty standard temperature fluctuation from the low 70’s at night to the mid 80’s during the day. With my AC unit I artificially capped the high temp at around 85 degrees. During the fall months I added under tub heat to keep a steady 85 degrees in the warm side of the cage while allowing ambient temps to drop in accordance with the outside environment. The winter and spring months fluctuated dramatically with regards to temperature. One week temps would consistently be in the 40’s in my garage while the next week would consistently by in the 60’s. I worried that such temperature fluctuation would cause illness. The coldest period was in early January when temperature readings in the snake cages were in mid 30’s. I did not think I could let it fall too much farther so I provided some external heat in the room that kept temps from falling below 38 degrees. Total artificial heat time was two days during the brumation period. Spring time warm up also had a large variance in temperature, although now under tub heat was provided.

Humidity;
- Humidity also showed great variance, although were consistently on the more humid side. As I stated before high humidity (Above 75%) combined with low temps (Below 55 degrees) worried me. The snakes never showed any ill effects of humidity changes.


Photoperiod;
- Fluctuated with the solstice. No attempt was made to alter photoperiod. No artificial light or darkness was ever provided.

Activity;
- During the summer months the snakes were active in the evenings and mornings. They were mostly inactive during the warmest part of the day. In the fall and spring, activity mirrored ambient temps in the garage for the most part. I observed the females more active at lower temperatures than the males. In fact, until I placed the males in the female’s cages in April, the males mostly stayed on the cool side of the cage away from the heat source. They were not very active, nor showed any interest in feeding at this time. During spring the females were active and roaming their cages even on cool spring days with ambient temps in the 50’s. I was surprised how cold tolerant the females were. Winter activity was scarce to non-existent. During brief warm ups, usually one or two of the snakes would come out of their hide box and explore a little. I observed every snake at one time or the other come out of their hide box and explore at some point during brumation.

Feeding;
- Feeding was aggressive for all snakes during the summer. The males slowed down and often only accepted a meal once every other week during fall. My males all stopped accepting food by the middle of October. The females showed an opposite response to feeding. Their feeding response was hyper aggressive all the way into late November. During spring warm up the same behavior was observed. The females came out of brumation on a mission to eat. They were fed aggressively and probably would have eaten more had I let them. The males pretty much refused meals until after copulation ceased in early May. The females were fed separately from males while the males and females were together and they continued to show a hyper aggressive feeding response. After copulation ceased the males became hyper aggressive with regards to feeding. The females began to show a reduced feeding response leading up to their pre-egg laying shed. The black pine snake and LA pine refused to feed roughly one week prior to the pre-egg laying shed. The Florida pine accepted a meal one week prior to pre-egg laying shed, but then regurgitated the meal three days later. I assumed this was due to mass effect, as her posterior body was very enlarged compared to the other two females. After egg laying all three females showed hyper aggressive feeding response again.

Copulation;
- I began introducing the males into the female cages within a day or two after the post brumation shed. Courtship behavior was immediately observed in all three species. As stated above, the Florida pine did not have a post brumation shed but when the male was introduced into her cage copulation was witnessed within an hour. I kept the males in the cages with the females for a three to four week period from early April thru early May. Courtship and attempted copulation was witnessed on a daily basis through this entire time. In early May all three males had ceased attempting to copulate and I took this as a sign that the deed was done.

Egg Laying;
- Activity from the females slowed considerably after copulation. They continued to feed aggressively, but mostly just stayed on the warm side of the cage. All three snakes started to show posterior swelling by the first week of May. This was most dramatic with the Florida pine which I would have guessed had 12 eggs insider her. I did not handle them very much, but did a regular health check every few days. From May 22nd thru May 25th all three females shed. I placed a hide box with damp moss in their cage after the shed and all three snake laid eggs within 5 days of their shed. The Florida pine laid one egg at the time of her shed. I placed it in the incubator, but it was clearly not viable and developed mold within three days of being in the incubator. Final results showed eight eggs laid for the black pine snake, seven eggs for the LA pine and five eggs for the Florida pine. The FL pine snake eggs were very large, followed closely in size by the LA pine. The Black pine snake eggs were roughly half of the size of the other two species.

Incubation;
- All eggs were incubated in a converted mini-fridge that I built myself. Temperature fluctuated between 83.5 and 84.5 degrees. Humidity remained 99%. The eggs were all incubated in Rubbermaid containers. The substrate was vermiculite.

Egg hatching;
- The eggs of all three species hatched after an incubation period of 62-65 days. Final count was 8 out of 8 eggs hatched for the black pine, 7 out of 7 hatched for the LA Pine, 4 out of 5 hatched for the Florida pine. All neonates were healthy, robust and without any defects. All hatchlings were between 18 and 22 inches in length. No clear difference between species in overall length. The Florida pine snakes in general appeared to have more girth. Sex ratios were 4.4 for the black pine snakes, 2.5 for the LA pine snakes, and 3.1 for the Florida pine snakes

Discussion:
Overall I was surprised at the amount of external variation in temperature was tolerable to the snakes. High low temperature ranges with standard deviation were as follows;
- June – October
High/Low 32 degrees
SD 13 degrees
- November – December
High/Low 34 degrees
SD 18 degrees
- January – February (Brumation period)
High/Low 37 degrees
SD 19 degrees
- March - May
High/Low 41 degrees
SD 22 degrees

The brumation period, January 1 thru March 1 was the only time that temperature was not manipulated to some degree. I did set this entire system up as a form of an experiment. I had several questions I wanted answered. I was worried that drastic temperature fluctuations during brumation would cause harm to the snakes. My first question was whether or not temperature fluctuation to this degree would somehow confuse the snakes into being too active during burmation and cause illness. Would the low temps combined with high humidity cause illness? Was the temperature going to be consistently low enough during brumation to allow for adequate spermatogenesis in the males? Finally, I wondered what affect these temperature variations would have on fecundity and whether or not one species would be affected more than the other species.
I observed no significant increase in activity during warm spells throughout the brumation period. Even at the highest temperature recorded (73 degrees) during brumation, the snakes showed no significant change in their overall decreased activity. Once the snakes experienced their first real decrease in temperature, they were done with activity until the March warm up. I do wonder what affect decreased photoperiod had on this decreased activity even during periods of mild temperatures. The snakes showed no ill effects from very cold temperatures (mid 30’s). I would have thought that temperatures this low would lead to illness and could lead to death. This was not the case. All snakes emerged from brumation healthy and robust. Low temperatures combined with high humidity did not seem to affect the snakes at all. With regards to spermatogenesis, results speak for themselves. All hatchlings were viable and healthy. I was surprised at the fecundity of the LA pine snakes. I am no expert, but a clutch of 7 seems high for this species. I would have thought the Florida pine snake would have had a larger clutch. Four viable eggs from a clutch of five eggs seems small, especially given the large size of my female Florida pine snake.
I noticed that during the spring warm up, the males tended to stay inactive and remained mostly on the cool side of their cages longer than the females. It is possible that this was some kind of self-regulation by the male snakes pertaining to spermatogenesis. The large variance in temperature combined with regulated supplemental heat or cooling allowed for the snake to regulate their own body temperature within their own cage, while still being exposed to natural temperature fluctuations. I think that this is likely consistent with what the snakes would be doing on their own in the wild. Why a certain snake choose to be colder or warmer on any specific day was not clear. For instance, I noticed that at times my female black pine snake would spend several days on the cool side of the cage (62 degrees) while the supplemental heat was available on the warm side of the cage (85 degrees). In general I was surprised how cold tolerant all of the snakes were. I observed clear changes in behavior in all snakes that seemed to be triggered by the outside environment. For example, all snake had a hyper-aggressive feeding response from June thru the middle of October. In the middle of October we had a cool snap that brought daytime temperatures in the 60’s and low temps in the 50’s. After this cold snap, all the males refused to feed. The females continued to have a strong feeding response, but less so than prior to the cold snap. Overall this was a fun, very non-scientific experiment. Attached are pics of the hatchlings and my garage set up. Thanks for reading.

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