Desert Tortoise: Twizzler

Posted at 8:55 am June 30, 2009 by Paula Kahn

Twizzler has a severe deformity caused by epoxy that was left on his shell when he was very young.

Here at the San Diego Zoo’s Desert Tortoise Conservation Center (DTCC) in Las Vegas, we have a number of special-needs desert tortoises that serve as wonderful education animals, and each of us has our favorites. Mine is Twizzler. He arrived here at the DTCC in 2007, and when he arrived, we found that he had hardened gray material all over the left side of his carapace (top shell), causing a severe deformity.

None of us had seen such a thing before, but we guessed that he must have walked through a construction site when he was young and had cement dropped or poured on his back. The natural growth on his right side indicates that he was likely covered in the cement for about 10 years. It wasn’t until months after he was brought in that another tortoise biologist told us that he was certain it was some sort of epoxy, and we could pick it off. Well, we spent months picking and delicately using a high-speed rotary tool to remove the cement. Although we were able to free him from the epoxy, he will never return to a normal tortoise shape, and because of that, he cannot be released because he would not be able to survive in the wild.

Well, that’s not the end of the story; a researcher visiting the DTCC recently came into my office where she saw Twizzler and exclaimed, “I know that tortoise!” She said that back in the early ‘90s, there were scientists conducting research on wild hatchling and juvenile desert tortoises. The researchers would attach radio transmitters to the tortoises’ shells to track them using telemetry, and after the project was over or when they could no longer hear the signal, they would abandon the tortoises, sometimes without removing the epoxy that kept the transmitters attached! Since the epoxy covered a large portion of the shell, including the seams between the scutes (sections of the shell), the tortoises grew up with severe deformities, if they grew up at all.

It took two days of scrubbing to get the toxic paint and sparkly glue off this pet tortoise when she arrived at the DTCC.

The moral of the story is this: do not attach anything to a tortoise’s shell, especially if it touches the seams! And on that same note, never paint your tortoise. A tortoise’s shell is highly vascularized, meaning it is full of blood vessels, so toxins may be able to get into the bloodstream through small openings in the shell and along the seams where tortoises may have suffered even slight injuries in the past. Instead, if you want to easily identify your tortoise, use a nontoxic paint pen and write its name and your phone number on its shell so you will be able to get it back if it’s lost. And an even better option to prevent from losing your pet tortoise, although you won’t be able to see an identifier, is to have your tortoise microchipped just like you would microchip your dog or cat!

Paula Kahn is a conservation program manager for the San Diego Zoo’s Institute for Conservation Research. See a previous post from her staff, Desert Tortoises: Lucy and Ethel.

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5 Responses to “Desert Tortoise: Twizzler”

1. Kris says:
   June 30th, 2009 at 12:13 pm

   I am very saddened to learn that research conducted to help us learn more about these wonderful creatures ended up causing them such harm! I am equally grateful to know your group is out there ready and able to rehabilitate them. What can be done about this? Many people are opposed to testing products on animals and things like that but, I, for one always believed that research to learn about the animals themselves was done with great care and respect for the species. I guess I am wrong.

2. Susan (UK) says:
   June 30th, 2009 at 12:33 pm

   Thank you for another instalment about the desert tortoises Paula. Each time you write the list of things people do to these poor things gets longer. Who on earth would want to paint the shell in snazzy colours? And I would have thought that researchers would have known better than to leave epoxy resin on the shell. I never knew you could microchip a tortoise though! Keep up the good work.

3. Paula from the DTCC says:
   June 30th, 2009 at 1:21 pm

   Kris,

   I like to think that wildlife researchers always have the best intentions, but sometimes we don’t learn until too late that we have done something that wasn’t really such a great thing for the species we are studying. The good news is that researchers today are extremely careful about applying epoxy to a tortoise’s shell, and they actually have to be permitted to do so by U.S. Fish and Wildlife Service. Sad story, but lesson learned. And Twizzler is quite a testament to how resilient tortoises can be!

4. zoodog says:
   July 1st, 2009 at 11:27 am

   Thanks Paula! Twizzler hears a Tweet…

   Moderator’s note: Yes, indeed. The San Diego Zoo has two Twitter accounts so you can get quickly get the latest news and fun updates on our animals. Visit twitter.com and search for “zooconservation” and “sandiegozoo”

5. Kris says:
   July 1st, 2009 at 1:09 pm

   Thanks for your response, Paula. I guess some things can only be learned through trial and error. Thanks for sharing Twizzler’s story.

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