Reptile & Amphibian Forums

Funky,
I gave you the ratios of the hatchlings this year compared to last year, except for the B&W Spitters. I was waiting for them to shed. I just sexed the B&W Spitter hatchlings. As I stated earlier, up to and including 2005 I was keeping my snake rooms at 85-86 degrees. I cooled my snakes and warmed them back up to 85-86. They ate, shed, and I introduced the females to the males at 85-86 degrees. They bred at 85-86 degrees. The eggs formed in the females, were layed at, and were incubated at 85-86 degrees.

This year I did everything the same, except at 81-83 degrees. Last year I got 17.5 B&W Spitters. This year I got 7.13 from the same exact pairing of adults. The female B&W layed 21 eggs both last year and this year, but one was bad this year. Almost very clutch of Corns, Kings and Cobras this year were even or female heavy.

I'm not the only one that has experienced this, so I have to think there's something to it. Whether or not sex is determined by temps, I'll stick to the lower temps. This may all be a coincidence, but it's a pretty damn big one if it is.

RC

There will be variances.
The proper way to study such a hypothesis is via the scientific method.

One approach would be to use several females of the same species. When a clutch is laid, it is split between two tubs, incubated at different temperatures.

You then look at the ratios and see if they are more than a standard deviation from each other. The more clutches the more statistical certainty you will have to demonstrate that some factor post laying affects the sex of the young.

This has been numerous times with TSD reptiles such as geckos, turtles, etc. - the experiment has probably been done with snakes.

Do you not find it odd that lots of instructions exist on how to hatch out male heavy or female heavy gecko clutches, yet none exist for any species of snake?

The reason is GSD. It's possible there are some species out there that are TSD but I don't know of a single scientifically documented case, while there are numerous documented cases for all other kinds of reptiles.

A friend of mine has 1 girl and 7 boys. Weird things happen. That's why you need a decent sample size in a controlled environment, preferable splitting sets of eggs from the same clutch (so that prelay conditions are identical)
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3.6 L. getula californiae - 16 eggs (Cal. King)
1.1 L. getula nigrita (MBK)
1.0 Pantherophis guttatus guttatus (Corn)
0.1 Pituophis catenifer catenifer (Pacific gopher)
3.3 Elgaria multicarinata multicarinata - 14 eggs (Cal. Alligator Lizard)

I see what you mean by splitting clutches up and incubating at different temps, but as I mentioned in an earlier post, what if temps during copulation and during egg formation inside the female have something to do with sex determination? Splitting the eggs up wouldn't prove anything.

I think if temps have anything to do with any species sex determination, why can't it happen during the formation of the eggs while still in the female.

Using different females could mess up the study, more than using the same female bred to the same male over several breedings. There would be less variables that way.

RC

There will be variances.
The proper way to study such a hypothesis is via the scientific method.

One approach would be to use several females of the same species. When a clutch is laid, it is split between two tubs, incubated at different temperatures.

You then look at the ratios and see if they are more than a standard deviation from each other. The more clutches the more statistical certainty you will have to demonstrate that some factor post laying affects the sex of the young.

This has been numerous times with TSD reptiles such as geckos, turtles, etc. - the experiment has probably been done with snakes.

Do you not find it odd that lots of instructions exist on how to hatch out male heavy or female heavy gecko clutches, yet none exist for any species of snake?

The reason is GSD. It's possible there are some species out there that are TSD but I don't know of a single scientifically documented case, while there are numerous documented cases for all other kinds of reptiles.

A friend of mine has 1 girl and 7 boys. Weird things happen. That's why you need a decent sample size in a controlled environment, preferable splitting sets of eggs from the same clutch (so that prelay conditions are identical)

>> I think if temps have anything to do with any species sex
>> determination, why can't it happen during the formation of the
>> eggs while still in the female.

It's possible it does with GSD - snakes are WZ chromosome which means it is the female gamete (sex cell) that determines the sex, not the male. Her conditions may impact which is more likely to be used. The eggs are already fertilized though by the time they are laid, so temperature of incubation will not impact the sex.
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3.6 L. getula californiae - 16 eggs (Cal. King)
1.1 L. getula nigrita (MBK)
1.0 Pantherophis guttatus guttatus (Corn)
0.1 Pituophis catenifer catenifer (Pacific gopher)
3.3 Elgaria multicarinata multicarinata - 14 eggs (Cal. Alligator Lizard)

I'm not very familiar with the scientific methods used (was a business major). Anyways, I find those results interesting. What would be the correct way to prove that the sex of the eggs can be swayed one way or the other by controlling the temperature of the females prior to laying.

Maybe a 4 year study. 1 year females are kept at low temps 81-83 as venomstreet had stated and eggs incubated at 81-83. Next year females kept at 81-83 and eggs incubated at 85-86. 3rd year females kept at 85-86 and eggs incubated low at 81-83. Finally females kept at 85-86 and eggs incubated at 85-86.

This would take into account both the temperature before the eggs were laid and incubation temps. Maybe if you had a large group of breeders and kept everything else constant this could provide some results. Heck, there's a little bit of luck involved in anything but if the numbers were staggering one way or the other it would seem you might be onto something.

Would there be a better way to try and test this hypothesis? This kind of stuff interest me for some reason. Maybe I should have majored in biology lol.

Numerous studies over the decades have been done on MANY snake species, yet not a single instance of TDSD has been found. It's not like this question hasn't been adequately addressed. Snakes utilise chromosomal sex determination, end of story.

Now, the notion that perhaps the conditions under which the female is kept might somehow effect the likelihood of one or another sex chromosome predominating is another matter. I am unaware of any such study. Certainly something to check out, but you would have to use many different females-after all, men in my family tend to father predominately male children. We must just have a lot of Y sex cells. Using many unrelated female snakes would correct for any such effect.

Brad Chambers

What was your hatching success?

Coincidence - do a chi-squared analysis if you want to test it. I really can't believe this is still be argued as many times as scientific analyses have shows TSD to not occur in these guys.
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KJUN Snakehaven