Reptile & Amphibian Forums

Even though I know there is TDSD in torts, I still think it is strange that animals are sold as certain genders as hatchlings. Does anyone have the "odds" of a temperature sexed hatchling being correctly sexed based only on incubation temp?

This is a great question. So far we have had little luck acquiring temp sexed tortoises. We have ended up with far more males than females. I am determined to find out this number with Pyxis arachnoides arachnoides. It will take me years to do it, but I am going to give it my all. I will let you know what I find out in 5 years or so.

In my experience of breeding tortoises (40 plus years), TSD works much better in some species of tortoises than in others. With G. elegans and G. platynota, higher temps (88-90F) produce females and lower temps (84-85F) produce males with almost 100% certainty. In Radiated Tortoises, the results are not nearly as reliable. There may actually exist a situation in Radiateds where the length and/or temperature of a cool down period prior to incubation as well as the incubation temp itself may influence the sexes of the hatchlings.

I cannot speak for the reliability of TSD in sulcata, Leopards, or other species, but my findings above (garnered from personally hatching a minimum of 138 of each race/species mentioned and tracking as many as possible to sexual maturity), indicate that it is to be considered fairly accurate (near 100%) in Star Tortoises and somewhatless reliable in Radiated Tortoises.

When buying animals represented as having been TSD incubated (or as a Sri Lankan vs. an Indian Star), you must buy only from people that you know and trust implicitly to avoid being duped. It is very similar to buying "hets" of a hot new Ball Python morph. If you don't personally own the snake's parents, what makes you really believe your normal baby is a "het" of whatever morph you hope to breed? Unfortunately, there are some unscrupulous types out there who take advantage of eager buyers by misrepresenting animals. This is more common when they know the truth will not even be learned for a few years, so the buyers must use common sense and caution to avoid disappointments.

With the advent of endoscopy as a feasible veterinary measure in tortoises, the sexes of young tortoises can be determined as early as 6 months of age now, and I expect that more and more reliable breeders will begin to offer "endoscopically sexed" tortoises in the future as opposed to "TSD sexed" tortoises. The cost might be slightly higher, but at least you can and will know exactly what you are getting from the outset. The other side of this coin is that after testing a good number of youngsters via endoscopy, breeders will know how their attempts at TSD are working, and then possibly can eliminate the need for endoscopy of their youngsters, (though there is a certainty therein which doesn't exist with TSD).

Cost for endoscope @ exotic pet vet in Houston....$1000

That is an extremely high fee. Many professionals set their fees very high for procedures they don't really wish to perform. Maybe that is the case with this place you contacted. You may need to go to a different office. Also check where the vet was trained to do the procedure. This procedure requires post-graduate training, after attending vet school. Many courses on it are given by UGA's Dr. Steven Divers, the pioneer of tortoise endoscopy.

My cost to have 10 (ten) Radiated Tortoises done last week at the UGA Veterinary Teaching Hospital by Dr. Divers was $500 (five hundred dollars). Normally prices run $50-75 per animal there. Cost is somewhat dependent upon the sizes of the tortoises, because they charge for the procedure itself and for the medications given, and lareger ones require larger amounts of meds.

If there is a vet school near you, check with their exotics department to see what pricing they would give you for the procedure. This worked out well for a friend of mine in CA.

Thanks I will try it. There is only one vet i can find here that can do it.

So, to summarize: the easiest, most reliable way to sex tortoises takes the longest time- wait until the animals are sexually mature and then look. Subadult animals can be sexed by endoscopy, prices and presumably quality of the person doing it vary greatly. Temperature dependent sex determination is an interesting phenomenon, but a sex-indeterminate hatchling is just that and buying a hatchling as "male" or "female" is making a possible error that can't be discovered for years.
Correct?

That is a very good summation of the facts of this matter. The only point I would reiterate is that temperature sex determination (TSD) DOES work very well in all the Star Tortoises, BUT the buyer must assume that the seller has good incubators which he checks frequently to see that they actually maintain the correct temperatures, AND is honest.

I have a 10 year old male hermanns that was incubated to be female. He only has 4 scutes instead of 5, which is not uncommon for a tortoise incubated at a higher temp. I assumed it was a female until he was about 4 years old & started humping all of his pen-mates.
-----
DeeCee

This statement from you describes the point I was making in this thread. Assuming that it is definitely a male, one would ask the following questions: Did you incubate the male tortoise yourself and what temp was used? If not, do you know the breeder of your tortoise quite well? Do you believe it was really incubated at a high temperature? And if so, do you think the breeder knows what temp to use to produce females in Hermann's Tortoises? Did any others from that same incubation turn out to be females?

I would ask these things because in my experience, tortoises incubated at the higher limits of the temps which produce females are more likely to have extra or split scutes, resulting in a higher than normal number of scutes rather than the too few scutes that you mentioned. The case you are describing (if I understand it correctly) indicates that two of the scutes are fused together into one larger one rather than an extra one forming, or a normal scute splitting into two smaller triangular ones, or even a small additional scute appearing where there would normally be a seam.

Without knowing what temperature was actually used for the incubation, I would say it was too low to produce females (or extra scutes) and/or TSD doesn't work well in Hermann's Tortoises.

That's another point: split scute hatchlings and their value. I always assume that an animal with EXTRA scutes or split scutes has been incubated at a higher temperature and is more likely to be a female. However, I often see split scute animals being sold for less than than "normal" hatchlings even though they seem to be more valuable to me because the gender is more likely known.

Beauty is in the eye of the beholder as the saying goes. There are a moderate number of people to whom the split or extra scutes are not a problem and they will buy the animals which have them all day long; there are far more people, though, who will NEVER buy an animal that has them, because they do not want to see "imperfections" in their animals. The are a very few to whom the extra scutes add value to an animal, as you seem to be indicating is your feeling.

The majority of the people with whom I have had dealings will not pay full price for any tortoise with abnormal scutes, either extra/split ones, or fused ones.

I have found the same thing with Mt.Tortoises that are of a medium price range. Tortoise collectors do not like inperfections in carapace scute formation. In the USA they have less value, in Japan they have no value, as in they dont even want to except an shipment of 50 or more to have ANY even in the slightest degree. On another point it is not always incubation temps. It could be genetic as I have proved with my experamentation in my breeding stock by using a different male for a female that through 30% distorted scute formation to less than 2%. My feeling on temp.related scute formation due to high temps is "why are only some split ect.and not all of the clutch". There are some Asian species that have even been Taxed out to have 4 or 5 Costals in their description. But for snake collectors the more destorted the "pattern" the higher the value. I have a few Zig-Zag-Motley Mountains that I have raised up. This year I will find out if its temp or genetic!. Vic.......pic......you cant see it but this girl has a Gular that is way off center pointing to her left.None of her offspring have ever had it. Her name Cruk Grue