Desert Tortoise Hibernation: Not for All

An ill desert tortoise enjoys the heat lamp this winter.

As our second season ends here at the San Diego Zoo’s Desert Tortoise Conservation Center in Las Vegas, the tortoises have gone deep into their burrows for brumation (winter hibernation). For the most part, this means we get to take a bit of a breather as well. However, there are a few tortoises that are not brumating this year due to health issues that we hope can be resolved over the winter months. These special tortoises are staying with me in the medical center until the spring. Although in most cases it is better (and necessary) for any species that would normally hibernate to do so, there are some instances in which it may be better for individuals with certain types of medical conditions to stay awake through the winter.

We have a few tortoises undergoing treatment for severe upper respiratory symptoms (cloudy nasal and ocular discharge and labored breathing). Although the treatment takes about two weeks, by the time their treatment ends, it is too cold for them to safely go out into a pen. Instead, they are staying in the medical center where their immune systems will have time to recover from their illnesses so that by spring, they will be strong and healthy again.

We also have a few very emaciated tortoises that we felt were too skinny to survive hibernation this year. Our goal is to fatten them up over the winter! With daily feedings, we hope to get their weight stabilized enough so that they will be ready to go back out in the spring.

The last few tortoises we have in the medical center are waiting to go to the Paul Harter Veterinary Medical Center at the San Diego Zoo Safari Park to have urolith (bladder stone) surgery. We get a number of tortoises each year that have uroliths that are too large for them to pass. This can result in a very long and painful death if they are not removed surgically. Our amazing veterinarian, Nadine Lamberski, has developed surgical techniques to safely remove these stones.

Since Dr. Lamberski has to work these unexpected surgeries into her normally very busy schedule, these tortoises are hanging out with me in the medical center until they can be transferred to the Safari Park. Don’t worry, though, that we are not acting fast enough to remove these uroliths; although tortoises can eventually die from them, they can actually live for years with them, which is one of the reasons that most pet owners don’t realize their tortoise even has one!  As they wait for their surgeries, they are happily munching away on hay and tortoise chow and spend most of their time comfortably basking under their combination heat and UVB lamps. The first two of these urolith tortoises will be headed to the hospital next week!

Rachel Foster is a research associate at the San Diego Zoo Desert Tortoise Conservation Center. Read her previous post, Tortoises Need Heat and Light.

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