Reptile & Amphibian Forums

Referring to the thread on incubation temps below and temp dependent sex determination, the two female heavy clutches I mentioned were produced the summer I had read what I thought was an interesting personal study someone had done regarding the effect temperature had on determining gender of hatchling corns, kings and milks. What he had suggested from his study was that it seemed as though temperature had played an important role in determining the sex of his hatchlings during the gestation period… the period of egg development while the egg is still inside the female, gravid as we commonly call it. He mentioned his little experiment began in 1989 and had continued along with his use of temps for some 16 years with virtually the same results about 99% of the time. I saved his data:

In 1989 I started a little experiment with ratios in mind. At the time I was playing with cornsnake patterns and wanted far more females than I was getting, so I tried this on three of my females:

I’ve used this system ever since on corns kings and milks and get virtually the same results every time, by which I mean about 99%.

Interestingly, that same year I had been trying to dial in the heat with the rack I’d built the previous winter. Using back heat set at 85 degrees; before I realized heat was building up slowly inside the tubs and the entire rack more than I would have liked and set it back some to keep things a few degrees cooler, my females were gravid and laying those two clutches that hatched out 2.6 and 2.9 at 84-85 degrees in the incubator. Essentially the same temps the females lived in while they were gravid. Whether or not this fellows data was accurate, I thought it was interesting that a similar thing seemed to have happened here with no intention of doing it, and the clutches hatched out female heavy.

Temp related sex determination while gravid? During incubation? Both? Or just luck of the draw?

Any thoughts?
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Mike

This is very interesting. Now my mind is wondering even more, right now i have a female suriname boa that is gravid i wonder if i keep her at the 90 degree temps will her babies be female heavy? I keep all my thayeri from 80-85 so maybe this is why i had the heavy male population last year? Since the second clutch was laid much later than the first her temps would have had to been hotter due to the fact it was summer and the temps rose naturally, this could have been why her clutch was female heavy.
thanks for sharing that info Mike, very interesting.
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Michelle
All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.

And after reading Shannon's post about the fellow that incubates on a shelf at very cool temps getting very large and healthy hatchlings and mostly females, it makes me wonder...

If in fact there is also a similar protein expressed by a gene on the Z chromosome in serpents that triggers male development as a secondary determining factor during incubation, and it is temperature sensitive, does it react the same way in both directions? In other words; is there a temperature range that it needs to be the most effective in triggering the development of a male embryo in snakes? Seems to be the case if you relate it to what happens with the Nile crock... the eggs require a specific range of between 89.6 and 91.4 degrees to produce males and anything warmer or cooler produces females.

Seems to be some sort of a relationship in all of this, doesn't it? Quite possibly a similar situation going on with our snakes that doesn't require quite the restricted range of only 1.8 degrees to determine male or female.

Interesting stuff indeed! It's beginning to sound as though slightly cooler incubating temps may be, for the sake of the snakes, a better way to go?!! Bigger, healthier hatchlings and if you want more females... find that cooler temp that makes it happen?

Hmmmmmmm.....
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Mike

now with corns you can keep them much warmer and a wider range of temps and they are still comfortable, but with thayeri you dont wanna jack the temps too high or you will be stressing the snakes out, so if this study was using a wide range of temps what would be the highest temps you would wanna go for? right now i am keeping Evelyn at day time temp of around 84 in one spot and the rest of her tub sits at room temps, her tub is on top of my tortoise enclosure and she is receiving belly heat from the UV light inside of the tortoise enclosure, i dont want to give her too much heat, because i dont want to stress her out while she is hopefully producing viable eggs. so what would you say is max temp to keep female thayeri at during her egg barring gestation period?

Adam

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6.6 THAYERI
1.2 SPLENDIDA
1.3 ALTERNA
0.0.1 CORN SNAKE
0.1.1 PYXIE FROG
0.0.1 MEXICAN RED KNEE
1.0 CHILEAN ROSE HAIR

...you tell me! I'm just picking brains here trying to learn something. I'm really just another newbie.

As far as maintenance temps for our animals is concerned, in my opinion we all know what healthy conditions are for our animals to live in... good temp gradients and constantly available choices, we allow them to decide and not force restrictions. I would never force my snakes to live in excessively warm temps for any reason.

Incubating the eggs is another story... what do you think?
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Mike

Personally i keep my helix set at 81F in my two racks for all my 05-06' juvies, Thayeri, Alterna, Splendida, and my one hold back Corn hatchlings from last year. they metabolize their food in about three-four days, and they never miss a meal,and never have a problem shed. so i actually prefer the lower temps verses the high temps for my collection, all my adults right now are sitting at room temps, except for Evelyn, who is getting a small amount of heat in her tub, i figuer that alittle more heat may help her in developing her eggs, and digestion, but i know too much heat is never a good thing, unless you wanna cook eggs. this year is my second year dealing (hoefuly) with eggs and my first year with King eggs. i plan to incubate my eggs at About 81-82. i have emailed a few people and i have read the prior posts about temps and i feel like that is a good middle ground from the answers i have recieved and from what i have read. i am just keeping my fingers crossed pretty much and hoping for the best, and once i see those heads popping out of the eggs i will be jumping up and down in celebration.

Adam

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6.6 THAYERI
1.2 SPLENDIDA
1.3 ALTERNA
0.0.1 CORN SNAKE
0.1.1 PYXIE FROG
0.0.1 MEXICAN RED KNEE
1.0 CHILEAN ROSE HAIR

That is a very interesting study, with some cool results. Really makes you wonder the possibilities for the future of snake breeding. Thanks for the info!
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©

Check this out:

"...I also review studies that examine the influence of incubation temperature on post-hatch locomotion performance and growth because these are the traits that are likely to have the greatest effect on hatchling fitness. The majority of these studies used artificial constant-temperature incubation, but some have addressed fluctuating incubation temperature regimes. Although the number of studies is small, it appears that fluctuating temperatures may enhance hatchling locomotor performance. This finding should not be surprising, given that the majority of natural reptile nests are relatively shallow and therefore experience daily fluctuations in incubation temperature..."

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Mike

Very interesting read Mike. Makes you think. Maybe you can set up a little experiment.........mike bod
Chris' Colubrids

Thanks to Michelle bringing up the topic and me reading through some of this stuff again, it does jump start the 'ol gray matter. I may consider slightly lower temps and a slight night drop.
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Mike

Very interesting post you made above, i am going to let temps flucate some and just see what happens. I have been wondering about the temps flucating in nature, so i am glad you made that post, thanks Mike.
I am also going to try with the suriname to let her temps flucate some also, I beleive in the wild this would be the norm and not just constant heat.
If all my thayeri breed and lay this year I am going to take 1 clutch and incubate them on a shelf, just to see, I will keep track of the results.
I do have a pair of hondurans right now that i am watching, they were not brumanated I just left them in the living room by a window, I only fed them when they hunted and became active, i didn't provide any heat to them, I put them together 2 weeks ago just to see and they are courting, I am going to let them play out and if they do breed incubate the eggs at room temps. i will let you know the results.
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Michelle
All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.

The hondurans are in large glass tanks, with hollowed logs to hide in and deep substrate, and on the north side of the house, so the temps flucate regularly, I have noticed in the morning when the sun comes out they lay on top of the log and are really a site to see.
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Michelle
All things bright and beautiful,
All creatures great and small,
All things wise and wonderful:
The Lord God made them all.

I usually incubate at 80-82 degrees with 80% humidity, and broke about even on the male/female ratio. I might turn it up a little, but then again doesn't mold grow faster at higher temps? I'm already having a problem with mold on my very first clutch. I've been using a q-tip to get it off. Is anybody else having a problem with mold, and if you've had one in the past what is the best solution?