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.
Hi Rachel: thank you for the update. I never knew before reading SDZ blogs that tortoises were having issues such as this… I do have a question about hibernation. What is the difference between brumation and topor? (From Suzanne Hall’s blog about the Polar Bears) Do tortoises develop stones because of their requirement for high doses of calcium? Thank you.
An interesting entry Rachel. Are these uroliths similar to a humans kidney stones and made of crystals from it’s own urine?
How the stone in tortoise develops?
Dianna and Lee,
Thank you so much for your interest in what we do here at the Desert Tortoise Conservation Center. First, to address the hibernation question, brumation and torpor are very similar behaviors. Brumation is a term that is used to describe a winter hibernation in ectotherms (animals that cannot regulate their body temperature internally, ie. reptiles and amphibians) and torpor is generally used to describe a similar state in mammals such as polar bears. They are both terms that are used to describe the winter slow down of activity, metabolism, and other physiological functions in many different species of animals. These are survival tactics that animals have evolved in order to survive environmental extremes. Desert tortoises may also go into a summer aestivation in order to survive the extreme heat of the southwestern deserts.
As for the urolith question, there are several causes for the formation of these stones. In desert tortoises, the two most common causes are improper diet, dehydration, or a combination of the two. Uroliths are made up of high concentrations of calcium, magnesium, phosphates, urates, and ammonium in the urinary tract. In dehydrated animals, these substances that are normally found in urine can become so concentrated that they bind together to form stones. If a tortoise is fed a diet high in these substances, then it can have the same effect as dehydration. If there are high concentrations of these substances in the urinary tract, then even a well-hydrated tortoise can have a hard time flushing them from its kidneys and bladder, causing them to bind together to form stones.
I hope this was helpful and have a happy new year!
Rachel – we have 3 desert tortoises in a large outdoor enclosure here in AZ. One seems very thin this fall – what can we feed him to put some meat on his bones? I’m afraid he will die in hibernation …thank you for any suggestions.
Beverly,
The most important time for tortoises to eat is during spring. If you try to feed him a lot now, that could be very problematic for him during hibernation since it can take several weeks for tortoises to digest food, and he needs to go into hibernation with an empty GI tract. You are right to worry about him, because tortoises generally do not lose weight over the course of a single active season unless something is wrong, either an illness, a bladder stone, or perhaps other tortoises are hogging all the food or bullying him.
Honestly, this calls for a vet visit to rule out a bladder stone or possible illnesses. We advise that you seek help from a desert tortoise-experienced veterinarian as soon as possible and be sure the vet palpates and x-rays your tortoise for a bladder stone first. The vet may also want to do bloodwork to look for vitamin and mineral deficiencies and to determine if your tortoise is dehydrated (be sure to increase how often you soak your tortoise to help keep him hydrated through this rough time).
Please make sure your vet has desert tortoise experience and not just “exotic” or general reptile experience, because desert tortoises are very different from other tortoises and reptiles. Wishing you and your tortoises the best. Please let us know how he is.
I’m interested in what kind of setup you keep for your tortoises when you’re preventing them from hibernating–particularly temperature-wise. We inherited a couple of desert tortoises unexpectedly, and upon taking them to the vet learned that one was ill and can’t be allowed to hibernate yet. I’m still trying to wrap my head around ideal temperatures for her. We currently have a large agricultural heating pad set up with a rheostat in our (unheated) garage, with a ceramic heat lamp in a corner for a temp gradient and a UV lamp for “daylight.” But we wonder if it will be enough to heat the enclosure from below, since the general air in the garage will potentially become quite chilly. Any suggestions? (And thanks!)