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Introduction

The following is an account of a successful breeding attempt in 2008, and a surprise, to me at least, of a second clutch in the same season. The male was not reintroduced after her first clutch.

After a relatively recent addition of a male Ladder Snake Rhinechis scalaris from Roger Butler, I wondered if I might be in with a chance of a successful breeding, as my ageing female might have been past her sell by date. Not that she wasn’t in very good health, having only previously being bred a handful of times in the (then) 17+ years of her life, it’s just that with the passage of age, it is generally assumed that fertility likely diminishes.

The male was young (18-24 months judging by size), although adult going into brumation, I felt that given a brief feeding in the spring, the male would be in fine fettle and make a suitable beau for my dam.

 

Brumation

On the 15th of December, 2007, I started to reduce temperatures by a few degrees every few days down to an unheated vivarium in an outside shed, where my snakes are kept. The arrangement in there allows for some ambient heat, as I also keep tropical species, so one side of the shed is permanently always heated. From previous experience, I know that on the ‘temperate’ side, the colubrids kept experience temperatures in the range of 14C throughout most of winter, on the coldest of freezing nights in mid-winter, the coolest I’ve measured temperatures in there has been 10C.

After acquiring the male, I decided to try to introduce him to my larger female. So after an uneventful brumation, I started to gradually warm them up to their usual temperatures on the 10thof March, 2008. When approaching their more usual temperatures of approximately 25-29C, I offered her a meal of two small mice to break her fast on the 24thMarch 2008, as she seemed active and her usual grumpy self. She refused this, obviously not quite ready and/or achieved the appropriate body temperature for long enough to facilitate its digestion. By the 30th of March, the enclosure had achieved its normal thermal gradient. Her activity level seemed affected more by daylight than the temperature, although clearly her ability to move was impeded when kept cool over winter. This could be gauged by the rate at which her tongue flicked and her movements overall, being less rapid at the cooler temps.

Her activity level seemed to increase as time marched on, I took this as a cue she was hunting and offered her another meal (a weaned rat) on the 4th April of that year, which she took.

Wooing the Dam

Following a few more meals for both the male and the female, I thought it about time that they became acquainted with each other. Making sure that both snakes had digested their meals and defecated, I deemed them ready for a breeding trial. The male was first placed in the females cage on 27th April, he at first seemed to be quite intimidated by her. I left them to it; he was hiding after initially trying it on with her, but being rejected by a series of strong body convulsions, throwing him off. Rejected, he retreated into a separate hide, the female usually likes to remain hidden in her hide and she was at this time however in plain view coiled on top of it. It was pretty clear who wore the trousers in this relationship at this time.

After not witnessing any copulation, despite a few attempts by the male, I separated them on 5th May. I then offered them some food, the male ate two small weaners and the female ate 3 weaners plus a day old chicken chick. These were definitely large meals; my thinking was that as these snakes tend to feast throughout Spring and Summer and eat hardly anything the rest of the year, I needed to provide enough nourishment not only for their active season but also for breeding. All my Ladder snakes tend to eat like crazy at this time and then by the end of the year, refuse some food from late August and around late September to mid October, finally losing all interest in feeding. The female had another meal prior to being reintroduced while the male refused any more food at this time.

Their second introduction was made on 22ndMay. Despite witnessing some infrequent half hearted attempts by the male, no copulation was observed. The male appeared less intimidated by the female at this point though, they could often be seen either together or in close proximity of each other. I assume that they must have mated at this point, even though I didn’t see them mate.

On the 8th of June, I separated them and offered them both meals before their next little liaison. Neither snake took any of the food offered, although the female would often press her nose into it, clearly disappointed that she wasn’t able to take the food at this time. She started becoming her reclusive self again, from what I saw she did look a little larger than normal, although at this time I couldn’t rule out the possibility that this was just the effect of her very large meal around a month ago and not a sign of egg development.

On the 12th June another introduction was made, the female seemed to come out to greet the male, with a hiss (I believe this is usual in humans too), she looked noticeably larger now. The male wasn’t discouraged from his advances and copulation was finally witnessed between the pair. It didn’t take long for them to start, within the first half an hour they were coupled, body jerks displaced some cage furniture and they weren’t the quietest of lovers. Copulation followed on and off for the next week or so with the male biting her around the neck area at times, I separated them on the 22nd June and noticed that the female was becoming blue. She completed this slough on the 29th of that month. She seemed active, as if looking for something, as there was already a box filled with damp sphagnum moss in her enclosure for laying eggs, I offered some more food, knowing she was laden with eggs, I made sure this was a small meal of three rat pups. She took these eagerly and would eat no more. It was only a little snack only, probably more a pregnancy craving, than any real requirement for food!

By the 8th July, I could see it was time to set up the incubator and on the 11th she had laid 5 eggs on the floor of her vivarium by 7am, underneath the newspaper lining, totally ignoring the nest box. She had settled in there on occasion before but evidently decided it wasn’t to her liking, for whatever reason. By 5.30pm that same day, she had laid the rest, a further six, so eleven eggs in total. Four of these eggs perished during incubation, some of them quite quickly. One hatchling was born deformed and died before it could exit the egg. It had managed to cut through the egg and was trying to exit. Over a few days, I could see something was amiss, after it died I cut the egg open and discovered why it couldn’t leave the egg. It was badly deformed with its body twisted and fused at a sharp angle, preventing proper locomotion and resulting in an obstruction for getting out of the opening in its egg.

 

Annual food intake

Below is a table showing annual food intake throughout the year, of both the male and female for comparison. An ‘X’ after the food item denotes when food was refused by the snake. All dates are DD/MM/YY.

Male Rhinechis scalaris meals offered

Female Rhinechis scalaris meals offered

24/03/08 2 small mice X

24/03/08 2 small mice X

04/04/08 1 small mouse

04/04/08 1 weaner

10/04/08 1 weaner X

10/04/08 3 small weaners

20/04/08 1 weaner

20/04/08 3 weaners + 1 chick

05/05/08 2 weaners

05/05/08 3 weaners + 1 chick

17/05/08 1 large mouse X

17/05/08 1 weaner X

18/05/08 – nothing offered

18/05/08 1 weaner + 1 chick

08/06/08 small mouse

08/06/08 1 small mouse X

22/06/08 2 large rat pups

22/06/08 1 weaner X

29/06/08 – nothing offered

29/06/08 3 rat pups

08/07/08 1 small mouse

08/07/08 – nothing offered

11/07/08 - nothing offered

11/07/08 6 small mice eaten eagerly

14/07/08 - nothing offered

14/07/08 2 large weaners

18/07/08 1 small mouse + 1 medium mouse

18/07/08 2 medium mice + 3 chicks

24/07/08 1 weaner X

24/07/08 1 large mouse

25/08/08 1 weaner

25/08/08 2 large mice X

08/09/08 - nothing offered

08/09/08 1 large mouse

10/09/08 - nothing offered

10/09/08 3 small mice eaten eagerly

13/09/08 2 weaners

13/09/08 2 weaners

17/09/08 – nothing offered

17/09/08 2 chicks + 1 weaner

29/09/08 1 weaner X

29/09/08 1 weaner X

12/10/08 1 small mouse X

12/10/08 1 weaner

15/10/08 1 small mouse X

15/10/08 1 medium mouse X

17/10/08 1 small mouse X

17/10/08 1 small weaner

 

All feeding attempts after this point were refused by both snakes, shortly afterward preparations for their brumation took place, with temperature again gradually lowered over the course of around a month.

Food intake and the first clutch

Prior to her first clutch that season and post brumation, she ate a total of eighteen food items over the course of just under three months in seven successful meal offerings. The first clutch was laid on the 11/07/08, although I cannot give an accurate duration for the egg-laying, it was first observed at 7am and by the time I had returned from work, at around 5.30pm, she’d completed her task.

She laid 11 eggs in total, the weights and dimensions are as follows to the nearest 5mm and whole gram. I marked all eggs in a permanent marker to follow their development using numbers from 1-11, ensuring I didn’t mix them up whilst recording the data. The egg measurements were recorded on the 15/07/08, I did not record their weights during incubation I’m afraid. All eggs looked fertile. All had a spongy tactile property, like water balloons at time of being laid. They did firm up a little during incubation. I don’t remember her previous clutches being quite so ‘squidgy’, I do remember however that despite their looks, I shouldn’t expect all of them to develop without problems and should expect some to fail.

Egg size

Egg weight

When/If hatched

Hatchling weight

Hatchling length

5cm x 3cm

28g

06/09/08

19g

29cm

6cm x 3cm

30g

Perished

-

-

5cm x 3cm

30g

08/09/08

22g

29cm

5cm x 3cm

31g

Perished

-

-

5.5cm x 3cm

32g

Deformed, died.

24g

26cm*

5cm x 3cm

29g

07/09/08

22g

28cm

5cm x 3cm

28g

Perished

-

-

6cm x 3cm

31g

06/09/08

23g

30cm

5cm x 3cm

29g

08/09/08

24g

32cm

5.5cm x 3cm

31g

07/09/08

19g

30cm

5cm x 3cm

28g

Perished

-

-

 

*This is an estimate of the total length, as this neonate was badly deformed and had rigid bends along its spine, this was the one referenced earlier that failed to exit the egg.

Food intake and the second clutch

Following her first clutch until her second one was laid, she ate a total of seventeen food items over the course of around two months in only five successful feeds. This was both due to my practise of alternating ad hoc the size and frequency of meals and not having large enough prey to offer her over fewer meals, exaggerating the effect. The second clutch was laid on 08/09/08. This was the second time she ignored the nest site I had provided.

This time she laid 10 eggs, with a slightly firmer feel, unless my tactile memory was playing tricks on me. She laid 10 eggs in total, the weights and dimensions are as follows to the nearest 5mm and the whole gram. Again, I marked them individually to aid in following their progress, throughout incubation.

Egg size

Egg weight

When/If hatched

Hatchling weight

Hatchling length

5cm x 3cm

29g

01/11/08

19g

28cm

5cm x 3cm

28g

02/11/08

20g

32cm

5cm x 3cm

29g

01/11/08

17g

30cm

5.5cm x 3cm

30g

02/11/08

22g

32cm

5cm x 3cm

27g

01/11/08

19g

29cm

6cm x 3cm

31g

01/11/08

23g

32cm

5cm x 3cm

28g

31/10/08

20g

32cm

5cm x 3cm

27g

31/10/08

20g

31cm

5cm x 3cm

28g

31/10/08

21g

31cm

5cm x 3cm

29g

31/10/08

20g

32cm

 

Both clutches were incubated at 27C +/- 1C, all eggs were placed on an almost dry bed of sphagnum moss in tubs, which in turn were placed in larger plastic tubs, with around an inch of water at the bottom. These larger tubs had lids clipped firmly in place and were then placed on the shelves inside the incubator, at the same level. The heating element is a ceramic tube heater, situated at the bottom towards the rear of the converted cabinet which was used as the incubator.

Weight of food and weight of clutches

The combined weight of food for this season (2008) prior to the first clutch being laid was 712g (to the nearest gram). The combined egg weight of this clutch was 327g. The eggs took 57-59 days to hatch at a temperature of around 27C.

The combined weight of food taken after laying her first clutch and before the second was 468g, the second clutch collectively weighed 286g and took 51-53 days to hatch at again, 27C.

Without a doubt the relatively high food count had something to do with her ability and possibly was the trigger for her to lay a second clutch. While she has been in my collection, she has never laid a second clutch. However, her previous owner once had a second clutch, as quite a few years have passed since his ownership of this scalaris, he can’t recall how fertile the second clutch was unfortunately.

I find it interesting to note that despite not being re-introduced to the male following her first clutch, her second clutch proved more successful. As both clutches were incubated under the same conditions, I can only assume that the first was least fertile, as I recorded no anomalies during incubation regards temperature fluctuations or humidity levels.

1st& 2nd clutch size/weight comparison

When comparisons are made with clutch size, entire clutch weight, number of hatchlings and min/max weight and length, we can see that they are pretty comparable with each other in respect of clutch size, hatchling weight and length. Where there is some disparity, is the number of hatchlings successfully hatching, and the combined weight of the eggs per clutch. I have discounted the deformed baby in these figures.

Clutch

Clutch size

Clutch weight

Number of hatchlings

Min weight

Max weight

Min length

Max length

1st

11

327g

6

19g

24g

28cm

32cm

2nd

10

286g

10

17g

23g

28cm

32cm

Conclusion

I’ve not kept this particular female since her hatching. I have known her from a hatchling however. She was then kept by another keeper, a close friend. I’ve known her for all but a few weeks of her 18+ years of life. Her temperament has always been changeable and she can still surprise me now, as this second clutch shows, it’s not just her temperament that can be polar in nature. Clearly, this mature ‘old’ ratsnake appears quite fertile, whether this is a result of infrequent breeding or pure chance of ‘good’ genetics, can’t be told. Despite the lack of a second re-introduction, the fertility of the second clutch was greater than the first, if anyone has any theories as to why this should or could be, please let me know. Also, if any R. scalaris breeders out there have had similar or dissimilar results, please let us know, your breeding accounts are always interesting to read.

I still find this species very interesting to keep, their characters I find most appealing. Many are drawn to more colourful or heavily patterned snakes. I seem to be attracted to these, my interest in them hasn’t waned over the years either. The perfect dull snake, for the not-so-perfect dull keeper? I think so. {/akeebasubs}

This site has information on the following genera of Ratsnakes ... Spilotes, Spalerosophis, Ptyas, Zamenis, Elaphe, Rhinechis, Senticolis, Pseudelaphe, Pantherophis, Bogertophis, Orthriophis, Gonyosoma, Oreocryptophis, Oocatochus, Euprepiophis, Coelognathus, Archelaphe