The Tiger Ratsnake (Spilotes pullatus) is also known as the Chicken Eater. It is a large arboreal colubrid found throughout South America. They are reported to exceed 3m but 2.5 is a typical average size for adults. There are several subspecies recognised but I have been unable to find any definitive data regarding these. Most animals seen in the hobby are usually wild caught and come in with other commonly imported South American snakes, such as Emerald Boas, Amazon tree boas etc it is usually very difficult to pinpoint even the country of origin, so specific locale data is rarely available.
Tiger rats are always described as a constricting species. I have kept several specimens of this species over a period of about 10 years, to this day have never witnessed even the slightest attempt to constrict. Most constrictors will, when hungry, constrict even defrost food. These snakes, in my experience, are pure grab and eat animals, which they do at an alarming rate. Living in the UK feeding of live mammals/birds is illegal, unless there is a risk of causing suffering to the ‘predator’ animal (through starvation). We therefore routinely feed defrost animals here in the UK. I have had to occasionally feed live, to get wild caught animal started, the prey animals have invariably been young (weaner) rats. Though these prey animals are not as dangerous to the snake, as would be an older specimen, there is still risk of injury to the snake. In all cases the animal was simple eaten alive. No care was taken regarding orientation of the prey animal, they were simply devoured.
A note here about food size, given the size of these snakes, it is easy to over estimate the size of food animal to offer, Spilotes will not eat large food items. Food items that would easily be consumed by similarly sized snakes of other species (large Elaphe, Pituophis etc) are typically ignored. Spilotes prefer smaller, presumably, easily overpowered prey.
I initially purchased a pair of long term captive animals, these were shipped from the other end of the Country, and were bought sight unseen! On arrival it was immediately obvious that I had a pair of males!!! Both animals were stunning snakes, so I decided to keep them and seek a female. I ended up buying another ‘pair” of imported animals, these were indeed a pair, the female was a typical specimen but the male is a striped morph and particularly colourful. The latter pair are the subject of this article. These animals were housed together in a tall vivarium, furnished with multiple branches.
The male settled in immediately and ate practically anything I offered of an appropriate size. The female however refused to feed. After a few weeks the female remained on the floor of the vivarium, oddly coiled such that she was in contact with all four walls of the vivarium, in roughly a rectangular coil. The cause of this behaviour was soon apparent when she passed several underdeveloped eggs. These were very small and slimy. Presumably, the stress of import and the numerous journeys, which had been subjected to prior to me acquiring them, contributed to the premature deposition of the eggs.
Following egg deposition, the female eventually began to feed but required three or four live feeds before she would accept dead prey. The female was always a more fussy feeder than the male. The male was/is such a good feeder that he took on a cylindrical cross section, rather than the usual tall “loaf of bread” shape. I maintained these animals for several years rather uneventfully. I attempted a few breeding attempts but courtship/mating was never witnessed.
A change of circumstances
Due to a change in my personal circumstances I had to move my snake collection to temporary accommodation, during house sale/move/purchase. Many of my snakes needed to be housed in much smaller enclosures during this period. The Spilotes were housed, individually, in large storage tubs for a number of months. The animals thrived. The female in particular became a voracious feeder and gained much body weight, the male never a shy feeder, fed more voraciously also. I moved into my new home in the summer of 2004. When setting up my snake collection, I chose to house the Spilotes in a similar manner to the temporary housing. I made a rack using the largest storage tubs I could find. Within the tubs I created a false floor with an integral climbing frame. This provided a secure hiding place for the snakes and increased the useable area of the tubs. The animals continued to thrive.
Once the snakes were settled in I planned a serious breeding attempt. During the winter of 2005/6, I allowed the rack containing the Spilotes to cool slightly for a period of three months. This was achieved indirectly by turning off a number of other vivaria to allow brumation, this reduced the ambient temperatures and indirectly the temperature characteristics of the Spilotesrack. I moved a number of species to this rack to condition prior to breeding attempts. Food intake naturally declined during this period. A combination of luck and cage placement made the cooling possible.
The animals ware housed together at the and of January, in a Nick Lumb 2’ cube vivarium, again a much smaller vivarium than would typically be used for this species. Approximataly two weeks later, a commotion’ draw my attention to the vivarium, the Spilotesware mating. This continued on and off (more on than off !!!) for over a weak. Food intake in the female declined but put this down to being housed with the male. There were no other signs that the famale was gravid, therefore I had not set up any appropriate nesting sites. On the 21st April, I discovered a ‘slug’ in the vivaria, I immediately provided nesting material. On the 23rd April two good eggs and another slug ware deposited. One egg was considerably larger than the other, the smaller egg had a discolored end but still looked viable. These were incubated in vermiculite at 28°C. During a routine check of the eggs on the 27th June, aftar 66 days of incubation, I discovered the smaller egg was hatching. This contained a striped animal which turned out to be a male. The other egg showed no signs of pipping after another 24hours, so being paranoid, I slit the egg to reveal a healthy snake within. I left the snake to come out on its own, this occurred on the 30th• This animal was a typical but beautiful marked maIe. After the post hatching slough the striped animal fed voraciously. The normal animal fed a few times but despite assist feeding quickly lost condition and died.
I am hoping to repeat this breeding success and gain further insights into this rarely bred species.
Reproduced with permission from the European Snake Society. Litteratura Serpentium Volume 26/4