Incubation temps and affect on sex and size

For the past 2 years of incubating the ball python eggs I have been taking meticulous notes on the temps, size, duration and sex. The other years previous I didn't pay close attention to it other than sex and morphs.

To my conclusion I found out the following to be true as far as my experiences:

Incubating temps 87-89 degrees Farenheit
- Eggs start to dimple around day 40
- Hatched in 55-60 day range
- Hatchlings were on the bigger side 70-88 grams (not one runt - woohoo)
- I got more females than males a 3 - 1 ratio
- Barely any yolk.

Incubating temps 89-92 degrees Farenheit
- Eggs start to dimple around day 40
- Hatched in 45-50 days
- Hatchlings were tiny! 33-70 grams. Not one over 70 grams.
*this could also have been on the small side due to small mother(1000-1300 grams) as far as the eggs with the 30-40 gram hatchlings. The others were more between 45-65 range.
- I got more males than females a 5 - 1 ratio
- Big yolks.
**In one of my clutches the eggs averaged 110-115grams, so they were on the bigger side. The babies hatched out of this clutch were only 55-70 grams. Yet, last year the same mother laid eggs weighing the norm 100 grams on average and they came out 80+ grams.

Note - I don't cut my eggs, they pipp on their own.

Now, I bring this up because a Reptile buddy of mine(feel free to comment you know who you are) told me the opposite affect as far as size and temp.

So, what is your experiences and provide details.
Egg Size?
Hatchling size?
Yolk?
Dead ones?
Sex?
Patterns? Boas tend to stripe when cooler temps are provided what about balls? anyone? anyone?
Temp? any spikes?
:weirdface

Pretty cool experiment. It's about time somebody looked for patterns in this. :)

I'm pretty sure your results on everything but sex ratio are probably accurate.

I'm 100% sure your sex ratio results are just a statistical anomaly. No known snake species experiences TDSD (Temp Dependent Sex Determination)-all that have been studied have sex chromosomes.

One piece of information missing is how many snakes are you basing this information on. Many have stated that lower incubation temps = bigger babies. However if it is based only on a few clutches the sex ratio could not be proven. It would require a large number of babies to make it hold water. I was male heavy last year, but this year I am hatching more females with the same setup. With a large enough sample it does all balance out.

Quote:

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Originally Posted by briz

One piece of information missing is how many snakes are you basing this information on. Many have stated that lower incubation temps = bigger babies. However if it is based only on a few clutches the sex ratio could not be proven. It would require a large number of babies to make it hold water. I was male heavy last year, but this year I am hatching more females with the same setup. With a large enough sample it does all balance out.

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About 35 BP eggs were recorded for this information.
Sorry such a late response.. been busy.

I also belive you need more information and more study. 2 year is not enough.

Actually, you would need more eggs and do the test at the same time. 2 group of population

but good to know :)

I cook all my clutches at 86.5-87. I would guess that longer incubation at lower temps would NOT lead to BIGGER hatchlings -- egg mass "is what it is". A 90 gram egg is not going to produce a 110 gram baby due to longer incubation. :)

Earlier this year...

Male yellow belly to normal female
6 eggs
90.5 to 91 degrees
52 days till pip
Cut the rest
Eggs dimpled at 42 days approx
Average hatchling size 59 grams
5 Female yellow bellys
1 normal male

Going to repeat temps again, same pairing, see what happens this season.

Yep, I agree that incubation temp has nothing to do with sex determination . . . however, there's some speculation that certain females tend to throw more females while others throw more males. Check your records again and see if a particular female tends to have more female offspring--it would be interesting to find out if this was true. It seems to be true with mine:

Female #1
7 egg clutch (5 hatched): 5 females
9 egg clutch (9 hatched): 7 females, 2 males

Female #2
7 egg clutch (5 hatched): 1 female, 4 males
7 egg clutch (7 hatched): 3 females, 4 males

However, I do believe that incubation temps can alter pattern and/or color. My first clutch of babies was incubated slightly higher than average (my thermometer sucked back then--I have since replaced it with a more accurate one). The thermometer I used back then said 90 degrees Fahrenheit, but it was +/- 2 degrees. I believe they were actually at 91 or 92, the higher end rather than the lower end, since they began hatching at day 49. Many of the babies from that clutch hatched out with very busy patterns and brighter-than-usual yellow color. The one I held back from that clutch has since darkened a bit, but still seems to have a lighter appearance. As babies, though, one in particular resembled a classic jungle (black and bright yellow--I wonder if the incubation temp is what makes classic jungles . . . could be a hot spot in the incubator for some clutches?).

Interesting theories for sure, though! :P

very interesting subject.. :)