Identification of the Chaco Tortoise

turtlesteve

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The topic of differentiating between Chaco and Sulcata tortoises has come up several times on the forum. Several folks, including myself in the past, have struggled to get this one right. So, here are some guidelines and photos (please forgive my bad photography) to aid with the process.

First, note that it is quite easy to recognize immature Chaco tortoises, as they look absolutely nothing like a Sulcata. What becomes difficult, however, is differentiating between an adult Chaco tortoise and a Sulcata in the 6-8" range, especially when the tortoise is gnarly looking, stunted, or deformed by improper care.

Note that Chaco tortoises were once imported into the US in the thousands, and they perhaps hold a distinct position as one of the least successful tortoise species ever imported, given how many came here versus the near total failure of this species to become established in captive colonies. Certainly the vast majority of these tortoises died within the first year, and the few survivors proved difficult to breed in captivity. Any eggs produced were unlikely to hatch, since development of the eggs is triggered by seasonal factors not recognized by keepers at the time (e.g. eggs generally fail to hatch if incubated at a constant temperature). Despite all of these factors, a handful of Chaco tortoises did breed successfully, and the F1/F2 offspring of these animals still exist in the US. Also, some individual tortoises that were young adults or juveniles when imported are still alive, and they pop up occasionally and seemingly out of nowhere.

1. Hatchling and juvenile Chaco tortoises. Coloration of juveniles is quite variable, the base color of the shell can vary from tan to dark brown. There is no mistaking these for a Sulcata.
hatchling.png Juvenile.png


2. Adult Chaco tortoises. Toenails and beak are dark pigmented, except in very light colored individuals. Marginal scutes barely connect or do not connect above head, patch of large scales on the thighs.
Chaco ID 1.png Chaco ID 2.png

3. A stunted Sulcata tortoise. Toenails and beak are not pigmented. Marginal scutes connect in a line above head, distinct conical hind leg spurs are surrounded by small scales. This particular tortoise was 6" long and over 10 years old.
Sulcata ID 2.pngSulcata ID.png
3a. The same Sulcata, a few months after rescue. No Chaco would grow this fast.
Sulcata 3.png



Finally: If you are reading this to ID a tortoise, and you do have a Chaco, please consider joining efforts to breed the species. The next question will of course be determining sex, which is not easy...
 
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