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Differentiating Male and Female Geochelone chilensis (Chaco tortoise) - Chris Tabaka DVM

Copyright © 2003 World Chelonian Trust. All rights reserved

Sexing Chaco tortoises can be relatively difficult as sexual dimorphism does not tend to take place until they are older.    There are also often problems associated with the first ova laid in this species likely due to developmental abnormalities in most captive specimens so knowing which sex you have is important.


Please also see the original care sheet by Chris Tabaka, DVM and Darrell Senneke, WCT trustees, on this species at:  Chaco Tortoise  ( Geochelone chilensis) - Chris Tabaka DVM and Darrell Senneke ( )




While some people will try to sex this species by the angle created by the anal scutes, I still rely primarily on the length of the tail .


Male Geochelone chilensis

Female Geochelone chilensis


As can be seen in the close-up below, the female's tail (on the right) is much shorter in length and is not held out to the side like the male's.


It should also be noted in this picture that the anal scutes in the male on the left form a wide open angle whereas in the female the angle is much more closed.   While this is not the most reliable indicator in my experience, it can be helpful in identifying sexes

Male Geochelone chilensis

Female Geochelone chilensis

Male Geochelone chilensis

Female Geochelone chilensis

  - World Chelonian Trust


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