Reptile & Amphibian Forums

I just sexed our last group of hatchlings and this year's results bear out my past experiences, as discussed earlier here on the forums. This year we again incubated the Louisiana Pinesnake eggs at 79-80 degrees (incubator stayed at 79 most of the time.). Of four clutches we got 4 males and 12 females. You'll remember that in '06 we did 84 degrees and got 12.4 and I swore (based on past experience) not to that again.

This has been our experience over nearly twenty years of breeding Louisiana Pinesnakes. I was one of the earlier Pinesnake enthusiasts and have produced hundreds of offspring from all of the races...many years ago. Presently I only work with Louisiana Pines. I have to admit that I don't remember every detail that far back and my notes are filed far, far away. But I do know that 79-80 is a standard I've used for most temperate colublid snakes throughout most of my career. In Pituophis ruthveni in my facility the lower incubation temperatures consistantly produce higher female counts.

So next year let's all take special note of our temps and sex ratios in all of the Pituophis native to the United States. We have a pretty big data base here and might be able to come up with some interesting results.

Cheers,

Terry Vandeventer

I'm incubating a clutch from a wild collected Trans-Pecos bull at a constant 82. I'll post the results in a week or so.

Brad Chambers

Hi Terry

I'm not as experienced as you in keeping and breeding but I have experimented a bit the past couple of years with incubation temps and found the same. My colubrid(mainly Lampropeltis and Pituophis) incubator is set at approx 78-79 F and never passes over 80. I also noticed higher female to male ratios with lower temps and also larger hatchlings compared to temps of around 82F. I've used 78-79F the last couple of years and 95% of the eggs have produced a higher female to male ratio so I stuck with it. I also know of another person that works with L.z.agalma and have noticed that lower temps (I think he uses low 70's) produced animals with more reduced black than if incubated at higher temps. Some people have said that incubation temps in snakes have nothing to do with the sex of the hatchlings but more and more people realize that it does play some role. Hopefully some more people will chime in. Thanks for sharing.
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Jonel M. Lopez

www.spsnakes.com

Just sexed a clutch of red bulls that were kept right at 80-81 degrees and the ratio was 7.5.

Scott Robinson

77-79 degrees produced 3.6 in black pines. Its starting to look like temps do determine sex ratios. It doesn't seem to be 100% but I think someone that has the means to should try incubating one clutch at say 75 and another @ 85 and see what happens. If several people did it I think it would be pretty conclusive that temps do determine sex in pits at least. I don't know if I would do it ruthveni but then again I don't have any.
Nate

If possible you really want to split the clutches - so that some eggs from a female incubates at one temp and other eggs incubate at a different temp.
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11.14 L. getula californiae (Cal. King)
2.3 L. getula nigrita (MBK)
1.0 L. getula floridana (Brooksi)
1.1 Pantherophis guttatus guttatus (Corn)
0.1 Pituophis catenifer catenifer (Pacific gopher)
0.1 Heterodon nasicus nasicus (W Hognose)
4.2.14 Elgaria multicarinata multicarinata - (Cal. Alligator Lizard)

I still don't believe incubation temperatures determine sex in snakes in general-there is just overwhelming evidence to the contrary (and what about pythons in which, outside of a very narrow temp range, the embryo just dies?). But there is a bare possibility that there are exceptions-very rare ones, but it IS possible.

So let's find out. Just remember, no rush to judgement. This is an extraordinary claim, and will require extraordinary evidence. Conclusive results will take many, perhaps hundreds, of eggs. Just the kind of thing the internet, and amateur herpers, were cut out for!

Brad Chambers

I'm not bought on the whole thing as of yet either. Yes my reds did come out slightly male heavy but last year, I had a few clutches that were kept at 78 degrees. They all hatched at exactly 63 days from the time they were laid. One southern pine clutch was 5.1, axanthic bull was 0.3, and patternless pines came out 4.3. This year, I did the reds at 80-81 and got the 7.5 but I'm doing the southern pines again (only 4 eggs) at 78 degrees to see what happens. There may be other factors needed. I think the splitting of the clutch is a great idea but you should do at least two of them.

Scott Robinson

I just had 2 clutches of black rats hatch. They were layed 1 day apart. They were incubated in the same incubator at 80 degrees. First clutch hatched at 57 days and was 3.5. Second clutch hatched at 62 days and was 5.2.