system
Given the following post, respond as if you're commenting on Reddit:
human
Why do Desert Tortoises release all bodily fluids when they're nervous/scared when Water is scarce in the desert?

It just seems like an illogical thing to do since they're just dehydrating themselves in an environment where water isn't as easily accessed.

I went on a field trip to an animal research facility for a Biology class and one of the caretakers were showing us a Desert Tortoise and explained that they release their fluids when nervous or scared (which it did a total of 4 times on the Caretaker while she was holding it).
gpt
Many animals defecate when scared as part of a predator defense mechanism.  Often this is especially bad smelling, sticky, forceful, or slippery.  You see this is reptiles, amphibians, and mammals.  It could easily be due to this, or as part of a relic behavior. 

A note on all the conversation about mutations on this page.  Mutations do not have to be beneficial to persist, they have to not be harmful.  This is a really important point in evolution that's often phrased incorrectly.  It's not really, " Survival of the fittests," as it is, "*Death of the least fit*."