Reptile & Amphibian Forums

I've talked to several breeders, many of whom sware that the sex of ball pythons cannot be "created" based on the incubation temps like you can with other reptiles. Others that I've talked to say that a slightly lower temp in the incubator can indeed produce significantly more girls than boys. Has anyone tested this theory for more than one clutch in more than one year? If so, I'd like to hear the results . . . . Thanks

I hope everyone has a safe, healthy and happy new year!
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Alice Cobb
Florida Reptile Room

snakes aren't sexed by temps......

..I've had too hot and too cold and the sexes are what they are........
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Literally decades of experimentation has invariably shown that snake sex is controlled by chromosomes, not temperature. Individual clutches which seem to have a skewed ratio are merely expected statistical anomalies. For example, I had a 5.1 clutch hatch this fall, at the same incubation temp I used for all my other clutches. Just a fluke, nothing more.
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Brad Chambers

The Avalanche has already started-it is too late for the pebbles to vote....

well according to all the research that I've checked, sex determination cannot be done with snakes. With that said, I've always ran my incubator at 88.0 F. The incubator fluctuates 1/2 of a degree both ways. We have been getting about 65-70% females for the last 3 years. This was the same temps I used for burms in the past and had very similar results. Now it's not that far from the supposedly 50% that you should get so I'm not certain it is temps and you add about 5-7 days more incubation time that you can mess up the eggs but it is easier to maintain high humidity without it being wet with cooler temps too.
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Josh & Krysty Hutto
J&K Reptiles

Various Ball Pythons, boas, dogs, cats, fish, an amel tiger retic female, a couple sulcatas and a few other odds and ends.

a BAD dog is MADE not bred, support the American Pit Bull Terrier as the greatest breed of dogs on Earth!!!!!

>> Now it's not that far from the supposedly 50% that you should get so I'm not certain it is temps and you add about 5-7 days more incubation time that you can mess up the eggs but it is easier to maintain high humidity without it being wet with cooler temps too.

...warm air holds humidity better than cool air does...
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"Polysyllabism in no way insures that what you're saying is actually worth being heard." - Blake (an e-friend of mine)

"I have never made but one prayer to god, a very short one: "O lord, make my enemies ridiculous." And he granted it." - Voltaire

other way around. The warmer the air, the quicker water disapates(sp) and thus lowering the humidity level. Do an experiment, put two identical containers with the same amount of water and substrate in each with the same humidity gauge in each (make sure they read the same at any given condition first). place one container in a place that is 91% and another at 88%. Let these sit for a day and I bet you a beer in daytona the cooler one will read higher humidity.
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Josh & Krysty Hutto
J&K Reptiles

Various Ball Pythons, boas, dogs, cats, fish, an amel tiger retic female, a couple sulcatas and a few other odds and ends.

a BAD dog is MADE not bred, support the American Pit Bull Terrier as the greatest breed of dogs on Earth!!!!!

Yes, water evaporates more quickly in warm air - which is why it's more humid! The water not in the substrate, not on a surface, is all in the air.
Don't believe me? Here's a few links for you:

http://www.wildwildweather.com/humidity.htm
(Check the Confused? paragraph)

http://wc.pima.edu/~bfiero/tucsonecology/climate/concepts.htm
(Note that that is a .edu site - so that's a college resource)

http://www.blueflame.org/datasheets/humidity.html
(This one says it right at the top)

http://www.uwm.edu/~kahl/100/pdf/Water vapor.pdf
(That's a college lecture in powerpoint)

You probably get the point now. Google "humidity" or "warm air and humidity" and you'll get the same links I did.

How were you measuring your humidity in your experiment, anyway? By how much water evaporated, or by an actual high-quality hygrometer? You used "%" when I think you intended to talk about degrees F (88% vs 90%), so maybe your way of measuring humidity is leading to false results...

~jenny
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"Polysyllabism in no way insures that what you're saying is actually worth being heard." - Blake (an e-friend of mine)

"I have never made but one prayer to god, a very short one: "O lord, make my enemies ridiculous." And he granted it." - Voltaire

your sorta both right, but I think Josh should still buy the beer. The reason Josh is right, is because his experiment is true, because you are measuring humidity relative to temp. expressed as a percentage, and a cooler temp. holds less water, so when surface area of water in the containers is equal the percentage reads higher in the lower temp. However Jen is right in that higher temp. can holds more water molecules, which means more moisture(water in the air) before reaching 100 %saturation and condensing. The other issue at hand with incubation is which is more important the amount of water in the air or the amount of water in the vermiculite (solid media). If you say media, it will stay moist longer with lower temps because higher temp will drive the liquid water in the media into vapor faster and thus drying out the media faster. If you say the moisture in the air is more important, then the higher temp would be better, because more water will be driven into vapor. You both owe me a bottle of Chimay Blue.
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1.0 pastel ball python
0.1 mojave ball python
0.1 normal ball python
0.2 3-toed box turtles
2.3 eastern box turtles
0.0.5 3-striped mud turtle
1.0 northern diamondback terrapin
2.1 tiger salamander
1.1 red-sided garter
1.0 anerythristic red-sided garter
1.1 Iowa snow plains garter
1.1 Het butter stripe cornsnake
0.1 anerythristic motley cornsnake
1.1 Blue garter (Puget Sound)

LOL.
I have NO idea what Chimay Blue is, but I'll agree that I owe you one for that.

~jenny
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"Polysyllabism in no way insures that what you're saying is actually worth being heard." - Blake (an e-friend of mine)

"I have never made but one prayer to god, a very short one: "O lord, make my enemies ridiculous." And he granted it." - Voltaire

Chimay Blue is a double malt trappist ale, brewed by the trappist monks, and it is the best tasting beer to my palete, you should try it, but be careful it has a high alcohol content
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1.0 pastel ball python
0.1 mojave ball python
0.1 normal ball python
0.2 3-toed box turtles
2.3 eastern box turtles
0.0.5 3-striped mud turtle
1.0 northern diamondback terrapin
2.1 tiger salamander
1.1 red-sided garter
1.0 anerythristic red-sided garter
1.1 Iowa snow plains garter
1.1 Het butter stripe cornsnake
0.1 anerythristic motley cornsnake
1.1 Blue garter (Puget Sound)

no in my experiment I used a high quality hygrometer (this was done in a college lab). As I stated I was measuring the amount of humidity levels of the air. Boxie stated the same thing I did but in a more technical verbage. Another way to look at it is this, as temps drop so does the dew point. As dew points drop it takes less water vapor to increase humidity levels. I will not debate whether warm air holds more water vapor because it does but it can hold alot more therefor requiring more moisture to reach 100%. This is relevant here so at 88 degrees for a temp you can have a drier incubation substrate to maintain a high humidity level versus 91 degrees in which you will need more moisture in the substrate to maintain the same high air humidity level. This is more beneficial with moisture sensitive eggs such as chondros and diamonds more than bp's but I still employ the same techniques for all python eggs and have yet to loose an egg to a problem with too much moisture.
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Josh & Krysty Hutto
J&K Reptiles

Various Ball Pythons, boas, dogs, cats, fish, an amel tiger retic female, a couple sulcatas and a few other odds and ends.

a BAD dog is MADE not bred, support the American Pit Bull Terrier as the greatest breed of dogs on Earth!!!!!

There was an article in Reptiles Magazine about switching sex of bearded dragons - apparently, temperature AND genetic makeup determines sex in those, and some other lizards. The gist of the article was that genes determine sex unless a temperature extreme is reached, and so genetic males would develop into physical females. Their theory was that the higher temperatures made the hormones responsible for male physical characteristics become ineffective.... So maybe with snakes the hormones that result in physical sex aren't affected by temperature extremes.
I personally haven't read or heard about any research done on snake sex determination, so I could be wrong.

Too many people have clutches that matter too much to them to fiddle with the temperatures (and possibly lose babies if things are just a little too extreme)...at least in ball pythons. Maybe a clutch of cornsnakes? Hehe.

~jenny
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"Polysyllabism in no way insures that what you're saying is actually worth being heard." - Blake (an e-friend of mine)

"I have never made but one prayer to god, a very short one: "O lord, make my enemies ridiculous." And he granted it." - Voltaire

Look at a couple threads on the Monitor Forum with some posts by Frank Retes. I really do think Sex determination in Reptiles and Fish isn't as cut and dry as people think it is. Some species of both Fish and Reptiles can in times of need, change thier sex ratios to even things out if thier is a high male/Female ratio. I'm not saying all can, but I do beleive thier is more in environmental factors sorting sex out than Chromosomes do any day.

that i before e rule is really confusing isn't it?
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1.0 pastel ball python
0.1 mojave ball python
0.1 normal ball python
0.2 3-toed box turtles
2.3 eastern box turtles
0.0.5 3-striped mud turtle
1.0 northern diamondback terrapin
2.1 tiger salamander
1.1 red-sided garter
1.0 anerythristic red-sided garter
1.1 Iowa snow plains garter
1.1 Het butter stripe cornsnake
0.1 anerythristic motley cornsnake
1.1 Blue garter (Puget Sound)