Carol Friend's account of keeping and breeding the Great Plains Ratsnake, Pantherophis emoryi.
The Great Plains Ratsnake (Elaphe guttata emoryi) is a less brightly coloured subspecies of the Cornsnake (E. g. guttata). It is similar in appearance to the Cornsnake except that the background colour of the Great Plains is light greyish with rich olive or blown blotches. In general, the Great Plains is slightly more robust in appearance than the Cornsnake.
Our snakes are an unrelated pair, which we purchased as hatchlings. The female was captive-bred in the U.S.A. and the larger male was captive-bred in the UK. Although both snakes fed regularly, the male always fed more readily and (more than three years later) still feeds more regularly than the female. The male will feed on small dead rats or large dead mice, whereas the female prefers dead mice and will only rarely accept a rat. Also, she will usually only take one food item and will refuse further offerings.
They bred for the first time in 1991, when they were almost two years old. It had not been planned to breed them at that time because of doubts that the female would be large enough to produce eggs safely, therefore neither snake had been cooled down over the winter period. However, both snakes had continued to feed well throughout the winter months and the female had grown considerably, so we decided to introduce the male to the female’s vivarium after she had sloughed in late April. No interest was shown by either snake on that occasion so the male was returned to his own vivarium. Further introductions were made over the next few weeks but, although the male made some attempts to mate, the female would not co-operate and no copulation took place.
During early June, it became necessary to house the snakes together, due to temporary lack of space and although no mating was observed it became obvious towards the end of July that the female was gravid. She had fed on a medium-sized dead mouse on the 16th July and then refused all food. She sloughed on the 5th August and on the 22nd August, she produced seven eggs. All the eggs were large (much larger than the eggs produced by E. g. guttata) and appeared to be fertile. Unfortunately, over the next few weeks the eggs began to spoil. When cut open, three eggs seemed to have been infertile and a fourth one contained a tiny dead embryo. The three remaining eggs still looked good.
On the 20th October, the first egg hatched, followed by a second on the 22nd October. The third egg failed to hatch and was eventually cut open. It contained a fully-developed dead baby. Hatchling Great Plains Ratsnakes are larger than those of the Cornsnake; although only slightly longer they are much sturdier and are able to eat larger pinky mice than the average baby Cornsnake will accept. Both of our hatchlings fed immediately after their first sloughs and continued to feed regularly, soon progressing to small furry mice and pinky rats. Both of these hatchlings were males.
Meanwhile, the female snake had begun feeding again three days after laying her eggs. She was fed as often as she would accept food over the next few months, in order to get her back into condition before the winter months, when it was intended to cool both snakes down for a period of hibernation. However, she would only feed around every ten days on average, so it was decided that she should be kept feeding for longer than the male. Therefore, on the 30th November the male was transferred to a box, furnished with a stout cardboard tube for a hide and a small bowl of water, for hibernation and the female was moved to a similar box on the 26th December. The cooling period lasted until 15th February for the female and until 22nd February for the male. The female did not accept any food until ten days after being returned to a warm vivarium, whereas the male fed within three days.
The female sloughed on the 12th March and the male on the 23rd March. The male was introduced to the female’s vivarium on several occasions during late March with no results. On the evening of the 3rd April, she was introduced to the male’s vivarium and he immediately began courting her. However, she still did not seem to be receptive but the male was persistent so they were left together over night. The female was returned to her own vivarium the next morning as the male was no longer showing any interest in her. The female fed surprisingly well for the next eight days, accepting three feeds during that time. She then sloughed on the 20th April and accepted a small dead rat two days later. On the 25th April, she was reintroduced to the male’s vivarium and copulation occurred within a few minutes. She was returned to her own vivarium afterwards. Following further introductions to the male’s vivarium, mating occurred on the 27th and 29th April. She fed twice after this and then sloughed on the 26th May. She refused all food after this date. On the 10th June she laid another clutch of seven eggs. As in the previous year they were very large and of good colour and appearance. The female accepted a medium-sized dead mouse the following day.
The eggs were put to incubate in damp peat in a plastic container with a thermometer inserted into the peat through a hole cut in the lid. If enough water is added to the peat initially, it is usually not necessary to add any more through spraying, since the moisture in the peat forms condensation on the lid of the container which then drips back onto the peat, but when one of the eggs was seen to be indented less than ten days later, the peat was sprayed to increase the humidity because healthy eggs will often indent slightly if humidity is low and will quickly recover when more moisture is added.
However, this apparently good egg continued to collapse and within a day or so was completely soft and had developed green patches (not mould). Unfortunately, the egg was firmly adhered to the others in the clump and it was not possible to remove it without disturbing the rest of the clutch.
By the third week in July, only three eggs remained. Three more eggs had failed in the same way as the first one. Of these, two had definitely been fertile. When cut open, both had contained a recognizable baby snake, but very small and pink, surrounded by a solid rubbery mass. The remaining eggs continued to incubate normally and one was found to be slit on the evening of the 8th August after fifty-nine days incubation. The following day, the other two eggs started to hatch. All the babies emerge from the eggs within twenty-four hours. As in the previous year, all the hatchlings were strong and healthy. (Also, they were all males!)
Throughout the incubation period, the female continued to feed moderately well and following the failure, for the second year, of over fifty percent of the clutch possible causes for the early death of the embryos were considered. At this time, the female was noticeably smaller and less bulky than the male and it seemed possible that the babies which died in the eggs were weak because the female was not as strong as she ought to be. Therefore, she was fed as much as she would accept, as often as possible, in order to increase her weight and get her into peak condition before cooling her down for a slightly longer period over the winter of 1992/3. During August, September and October, she was fed twice each week on the largest dead mice available. She would not accept any rats during this period and only once fed on more then one mouse at a feed, although she was offered a second mouse every time. She had her last feed on the 24th October and the hibernation period began about four weeks later for both snakes. They have been checked regularly throughout the winter and, at the time of writing (early February, 1993) the female compares favourably with the male in both size and condition. Another breeding attempt will be made this year, hopefully with better results!
The Great Plains has never attained the popularity of the Cornsnake, but it is equally beautiful, despite its less gaudy colouration, and deserves to be kept and bred in larger numbers than it is at present. Hobbyists considering keeping the Great Plains Ratsnake should not be deterred by the poor results detailed above, they are not typical; I have since spoken to at least one breeder who successfully hatched all the eggs in a clutch of ten without any problems.
Editors Note: With thanks to the Reptillian Magazine for permission to print this article.