"Because desert tortoise live in an arid climate where most of the rainfall occurs during the monsoons, it is able to store water in its bladder for use during drought. It can go over a year without drinking. One of its defense mechanisms when handled or disturbed is to release the contents of its bladder, which can deplete its water supply and can cause harm or death during a drought. For this reason, if you find a desert tortoise, do not pick it up."Interesting that it can harvest water from the bladder. Mammalian bladders have a transitional epithelium that is virtually impermeable to water. But I found an NCBI article that documents reabsorption of water from Gila monster bladders, so presumably the same adaptation has evolved in tortoises.