An elephants built-in water tank

You may have noticed elephants with a leakage from their temporal glands. This means that they are experiencing some kind of stress. It could be a female worried about protecting her calf or simply heat stress. Interestingly, there have been many accounts of elephants quite far from the nearest water source regurgitating water, collecting it from their mouths with their trunks and spraying it behind their ears to cool down. When this action was first observed many years ago there were two plausible sources for this water: the stomach and the pharyngeal pouch. The contents of the stomach are very acidic which can lead to irritation of the skin and hence did not make sense. And elephants were also seen spraying themselves while walking or running when it is difficult to regurgitate water from the stomach. The actual source of the water used to spray themselves turned out to be the pharyngeal pouch which is situated behind the tongue. This pouch can also be used for heat absorption, especially around the brain located just above the pouch.