I just crunched a few numbers. These averages are from the last 30 successful births of Colombian Boas that I have records of an observed ovulation. Taking all 30 into account the average gestation period from an observed ovulation till the date of birth was 123.9 days. I had made the determination that the average gestation period in Boa Constrictors was 124 days 17 or 18 years ago. That is sort of the industry standard we have gone by since then. However, the reason why it is at 124 days is in large part because there will always be three factors in play. 1. The misidentification of ovulation. 2. Failure to observe the second more important ovulation. 3. The occasional female that holds her babies much longer than necessary for some unknown reason.
Below I have taken the five highest total gestation length records within these 30 litters and include the number of days from ovulation till the POS "Post Ovulation Shed". The numbers are total gestation period in days followed by the number of days from the noted ovulation till the POS.
136 - 51
136 - 19
134 - 29
134 - 25
133 - 28
Note how four of the five have much longer than normal periods from ovulation till the POS. Females usually shed 16 - 20 days after ovulation. Only one of these females falls within that range. Each of the others go from 25 all the way up to 51 before having the POS. So I submit that I likely did not observe as closely and missed another ovulation or the actual more obvious ovulation was missed due to my belief that it had already occurred.
So I took the remaining 25 successful breedings and crunched the remaining numbers. This brought the average gestation period to 121.8 days shaving 2 days from my previous estimation of the "normal" Boa Constrictor gestation period. I am now going with the 122 day gestation period vs. the 124 days. Additionally, it is interesting to note that ten of the litters in this sampling had full term little ones short of the 120 day mark. What I am really most interested in isn’t finding a true average, but the actual gestation period typically necessary to produce full term babies.
The reason for my agonizing over this is I have one female that did NOT give me a POS that giving my ulcers as I wait for her babies. She has been making a nest and acting like she is about to have those wigglers at any moment for more than a week! She had a nice ovulation January 22nd. I had entered the standard 124 gestation period into my spread sheet that calculates my Boa’s due dates for me which puts her due date at May 26th. I can't imagine her going that long judging by her current behavior so I crunched, looking for a possible tightening of the length of the gestation period to make me feel more at ease with the very short term future.
So now I believe she is actually due May 24th! Today she is at 120 days after ovulation so only two days till she reaches the new “average”! Somehow, that makes me feel a lot more comfortable... sort of...
Here is the bad boy that bred that girl for me:
Her? She is mostly yellow.
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Jeff Ronne Sr
The Boaphile
Director USARK
Originator of Boaphile Plastics
The Boaphile Boa Site
