# sexual dimorphism



## deadheadvet (Jan 23, 2017)

In my opinion, temperature sexing for the most part, is a bunch of crap. There is always variation within the temperature of the incubator. Every time the door is opened, the temperature is affected. I am so sick of these breeders flapping their gums that they are this sex or that sex because they say so. The only way to tell is when they are big enough to visibly see the sex or scope to verify type of gonads present. Any time one of my tortoises are up for sale, if sex is unknown it is UNKNOWN. Not temperature sexed female or male. How do you even know that you can trust the breeder to tell you the truth as to how they were incubated. You want the true sex, then get proof they were sexed or do not believe what you were told. Not every species of turtle or tortoise can be sex steered via temperature.


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## Sterant (Jan 24, 2017)

In case you want to read up on sexual dimorphism in radiated tortoises.

http://www.chelonian.org/wp-content/uploads/file/CRM 6/18-Leuteritz&Gantz.pdf


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## dmmj (Jan 24, 2017)

they say temperature sexed female because they can get more money for them


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## Kapidolo Farms (Jan 24, 2017)

https://scholar.google.com/scholar?...ved=0ahUKEwi55Pf069vRAhWE7xQKHUz-CjEQgQMIGDAA

All these scientists just spouting off a "bunch of crap", yeah, I don't think so. Breeders may be covered with dmmj observation, but it's real science.

There may indeed be subtleties not well established but it's not a bunch of crap. Diapuse is one of those issues. But it's not a bunch of crap.


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## deadheadvet (Jan 24, 2017)

Scientific determination is one thing. Under controlled circumstances there is absolute validity in the determination of sex within a species of Tortoise.
I am not disputing that assertion. My complaint is directed towards hobbyists and breeders who are claiming the sex based on the temperature of the incubator. That is where I have a big issue. There is no proof that the sex will be as promised. (until 4-10 years later) Buyers should be prepared that the desired outcome might be wrong. How do you know that a breeder might claim that the eggs were incubated for female and were actually incubated for male to control competition with fewer females since they seem to be more desirable. This is why I will say unsexed and leave the statement to stand on its own. I personally have a tortoise that was promised to be incubated for female and it is definitely a male. My tough luck.


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## Kapidolo Farms (Jan 25, 2017)

deadheadvet said:


> Scientific determination is one thing. Under controlled circumstances there is absolute validity in the determination of sex within a species of Tortoise.
> I am not disputing that assertion. My complaint is directed towards hobbyists and breeders who are claiming the sex based on the temperature of the incubator. That is where I have a big issue. There is no proof that the sex will be as promised. (until 4-10 years later) Buyers should be prepared that the desired outcome might be wrong. How do you know that a breeder might claim that the eggs were incubated for female and were actually incubated for male to control competition with fewer females since they seem to be more desirable. This is why I will say unsexed and leave the statement to stand on its own. I personally have a tortoise that was promised to be incubated for female and it is definitely a male. My tough luck.



So I find we agree with Captain Awesome. When people press me for what sex I incubated for, I just tell them the incubation parameters and let them determine what that may mean or indicate. I figure if you want me to say you are asking for an intimation of guarantee. If you can't sort it out for yourself based on my description of the incubation parameters then your also likely not able to manage a collection for breeding. 

As for crap information, oh yeah, there is a truck load out there. Not just on stymied husbandry techniques, but outright falsehoods on the history of the animal.


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## dmmj (Jan 25, 2017)

The biggest problem in my opinion is that people don't know that temperature sexec for one gender or the other doesn't mean they're all going to be that gender it just means there is a higher percentage of that particular gender but there's no guarantee one way or the other what gender you get but breeder say temperature sexed for female because they know they can get a higher price for radiated females than males.


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## dmmj (Jan 25, 2017)

I know the science behind it is sound because they've done studies mainly on alligators and crocodiles in Africa but I also know that the temperature difference of one degree could drastically alter the ratio


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## ZEROPILOT (Jan 25, 2017)

deadheadvet said:


> Scientific determination is one thing. Under controlled circumstances there is absolute validity in the determination of sex within a species of Tortoise.
> I am not disputing that assertion. My complaint is directed towards hobbyists and breeders who are claiming the sex based on the temperature of the incubator. That is where I have a big issue. There is no proof that the sex will be as promised. (until 4-10 years later) Buyers should be prepared that the desired outcome might be wrong. How do you know that a breeder might claim that the eggs were incubated for female and were actually incubated for male to control competition with fewer females since they seem to be more desirable. This is why I will say unsexed and leave the statement to stand on its own. I personally have a tortoise that was promised to be incubated for female and it is definitely a male. My tough luck.


Your point is understood and I'm in agreement.


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## Markw84 (Jan 25, 2017)

I will agree somewhat with @deadheadvet and perhaps phrase it differently myself. The way some breeders use TSD for selling what they SAY is a particular sex is a bunch of crap. I agree with all that has been said here so far. And I do believe that TSD can be a very useful tool. As we learn more and more, and techniques improve, I feel it can be an even more valuable resource.

CAVEAT EMPTOR!! More important here than ever.

I believe what we are seeing, is that it is very important to consider the source and ask the right questions. Just as it is so important to find how the hatchlings were started, as we've too often seen on this forum. If seeking a particular sex, when sex cannot be verified for years, the details of how and why a gender is being stated is important to discuss to try to make a determination of how accurate it may be, and if appropriate attention to detail, in that regard, was actually made in incubation.

In most species studied so far, the sex can be virtually 100% at certain temperatures. But yes, it can be just a few degrees that will change that dramatically. So how accurate is the incubation techniques used? Thermometers that most use are at best accurate to within a few degrees F themselves. Themostat accuracy must be considered. Is the thermostat switch or proportional? There is a temperature sensitive period that is most critical, and it seems temperature hours above a certain temperature during that period is most important. Was that considered by the breeder? Although opening the incubator for several minutes has little effect in my experiments, fluctuations in room temperature where the incubator is will have effects despite the thermostat setting. Was the temperature monitored by daily or weekly visual checks or was there a data logger? Was the reading from inside the incubator, or actually from in the container next to the eggs themselves? Was humidity maintained consistently? Can you get a record of actual temperatures throughout the incubation period?

I think these are all valid questions, and if asked to pay more for a certain likelihood of a particular sex, it should be expected.

So I do believe there is a place for the use of TSD and it does have potential value in the marketplace. It certainly has great value in helping to develop more productive breeding groups to help weight towards a specific sex. But it is indeed open to misuse and outright deception.

So we are back at the recommendation that the choice of a very trusted source is so very important.


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