By Margaret A. Wissman, DVM, DABVP
Q. My star tortoise's feces are sometimes white in color. I don't know if I was giving my tortoise too much calcium supplement for the past two weeks. I used to sprinkle some calcium on the green vegetables. I've now stopped using the calcium. My tortoise does not pass white feces every time. Every few days it will pass some white feces along with the green feces. What should I do?
Steven
A. I think it’s time for you to have a lesson in scatology (the study of feces, poop, doo-doo or excrement). I don’t know how long you have owned your tortoise, or if you have been observing its droppings for long, so I will start by giving you the basics on tortoise feces.
The normal feces of a tortoise consists of fecal material. This usually appears as an odiferous formed mass consisting of the end products of digestion. The color, consistency and volume of the feces will vary depending on what the tortoise is ingesting. But for the most part, the feces will be brown or greenish-brown.
Tortoises also produce urine and urates. Urine is the liquid portion stored in the urinary bladder. Urine contains waste products and toxins that are filtered from the bloodstream. Reptiles also have one more type of excretion product, called urates or uric acid. This is the end product of protein digestion and is also stored in the urinary bladder as a creamy, off-white pasty semi-solid. In reptiles, uric acid is cleared from the bloodstream by the kidneys. When the tortoise urinates, it will pass the liquid urine and the semi-solid urates at the same time. A tortoise may urinate and defecate at the same time, which may leave urate deposits on the fecal material. This will make the feces appear as if it is white or off-white. I suspect that is what you are seeing.
Another possible explanation is that the tortoise feces are old and sun-bleached; as that can cause feces to appear whitish over time (although I don’t think this is what you are observing).
A tortoise may urinate or defecate independently of one another, but as I said, both liquid and solid are often passed simultaneously. I suspect that you are seeing urates being deposited on the feces being passed by your tortoise.
I would recommend that you take some photos of the tortoise feces that you are worried about, and also collect some fecal material, storing it in a sealed plastic bag or container. Make an appointment with your herp vet (and I have discussed how to find one in previous answers if you don’t have one already lined up) and bring in the fecal specimens with you to show to your herp vet, who may wish to do some testing on it in order to determine if there is a problem or not.
I hope this helps you to understand the differences in excretion between humans and reptiles, so that you will better be able to evaluate the tortoise feces, to determine whether they are normal or not.
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