Sexing by number of tail scales

[Eredant]

Whilst reading some husbandry literature (Raising giant tortoises; https://www.zora.uzh.ch/id/eprint/10240/2/ZAWAM_6V.pdf quite interesting) I found a reference to this paper (Captive breeding of Dipsochelys giant tortoises; https://pdfs.semanticscholar.org/1709/ad97e7b851b9795409fc9a8d56d47e3633c5.pdf) in which they discuss the practice of counting the number of tail scales, to determine the sex at young age. Presumably the number of scales doesn't change as they grow and males have a larger number of them (12-14) than females (8-11).

Does anyone have any experience with this practice/method? @ALDABRAMAN perhaps?
Could anybody explain which scale’s they’re actually talking about? It isn’t exactly clear to me which scales they’re counting.

Interestingly I also came across this video from FloridaIguana in which he’s trying to work out a formula based on proportional tail size compared to the tortoise’s length.

Note: It doesn’t actually matter all that much what their sex is to me, but I'm curious and it would be nice to not have to wait 15 years .

 

[ben awes]

time to start counting scales everyone! Seems an easily tested theory. I;ve got three, ages 4,4, and 7. I don't know their sex yet, but I suspect my oldest is female.

 

[ben awes]

and thanks for sharing the links - very interesting and must reads for us Aldabra owners. btw, the paper you linked that was supposed to reference scale counting did not mention scale counting that I could find, but the first link did talk about it. Great post!

 

[Eredant]

and thanks for sharing the links - very interesting and must reads for us Aldabra owners. btw, the paper you linked that was supposed to reference scale counting did not mention scale counting that I could find, but the first link did talk about it. Great post!

The 2nd link is the reference that they give for this scale counting in the 1st link. You're right that the 2nd link doesn't give more information, just a reference to a personal communication. Not exactly the type of scientific data that you'd expect to get from a reference. To be honest I don't even know which scales to count. I figure that with a good picture of the tail one would be able to count these scales even at very young age, if you know what to look for.

An alternative sexing method may be possible using the external morphology of the tail. This is distinctly longer in adult males than in females, but no such difference is present in hatchlings. As the tail elongates males do not grow additional scales but expand the existing scales, thus the number of tail scales gives an indication of the adult tail length (I.R. Swingland pers. comm.).

 

[Eredant]

Giving this a bump, would be really informative if someone with adult Aldabras would check this theory with their animals!

 

[wellington]

Is this only for Aldabras? Would love to find a sexing way for hatchlings of all species.
@ALDABRAMAN start counting lol