This article first appeared in the July 2008 edition of our Ratsnakes Digest and is a brief report of extended incubation in Coelognathus helena helena.
After infrequent brief introductions, my female Trinket Snake lay five eggs on 13/2/08, it is possible that they were actually laid a day before, as I was out that day. Four of which looked good, one was clearly infertile due to having a darker appearance and being harder to the touch. All eggs were numbered to record their development throughout incubation. There measurements when laid were taken, egg dimensions, a brief description and their weight were as follows:-
1. 4cm x 1.75cm - looked fertile & good 9g
2. 4cm x 1.75cm - looked fertile & good 9g
3. 4cm x 2cm - looked fertile & good 10g
4. 4cm x 1.5cm - looked fertile sunken, possibly squashed by the female, requires hydration 8g
5. 3.5cm x 1.5cm - looked infertile 5g
I chose to incubate all eggs at an overall lower mean temperature than the norm (27-28C/80.6-82.4F), the temperature range was from 21-27C (68.9-80.4F), mostly the eggs endured temperatures between 24-27C (75.2-80.4F).
By 22/2/08, number 4 egg, the squashed one, started to look yellow where it was constricted at its narrowest point. Numbers 1-3 still looked white and healthy however. Number 4 egg started to develop mould at its narrow point and was becoming discoloured. This egg never filled out and had clearly failed by 24/02/08. Egg number 3 was the next to fail, turning slightly yellow by 28/2/08 and then obviously yellow by 10/03/08, two days after this egg started to develop mould, so was separated from the others. A few days after this I cut this egg open to discover it was solid!
On the 14/5/08, the eggs started to hatch, some 91 days after they were laid. One hatchling emerged from its egg on the 14th, while the other hatchling only poked its nose out of the egg, emerging the next day (day 92).
Egg 1 measured 4cm x 1.75cm when laid, at time of hatching measured 5.5cm x 2.5cm and the resultant hatchling measures 29cm (snout to tail). This baby seems to have more girth, overall more robust and feisty.
Egg 2 measured 4cm x 1.75cm when laid, at time of hatching measured 5.2cm x 2.3cm and the resultant hatchling measures 28cm (snout to tail). This baby has good body proportions but is slighter in build than the first one, overall slighter and seems more relaxed.
Both hatchlings appear healthy and take pink mice current, the largest now takes these two at a time.
Sue Knight amongst others (Trevor Smith for instance), have reported a curve at the extremity of hatchlings tails; this appears to be a temporary effect, as it grows out without any damage to the tail. The cause of which has been attributed to lower incubation temperatures. As neither of mine exhibited this phenomenon, I assume that it was a sharp drop in temperature from the normal incubation temperature,rather than a low temperature that may have caused this effect.
I currently have 6 eggs from the same mother C. helena, these will be incubated at a more even temperature of 27C (80.4F). I'll be reporting the total incubation time, size when laid, dimensions at time of hatching and snout to tail measurements of the babies when born, for comparison.