Animals have this ability to find water, and it has always been a mystery to me. On a series like Discovery Channel's Planet Earth, you see footage of animals trekking great distances to watering holes, but the holes may not be where they had been in previous years. So how do they do they find the water?
Water has a smell.
It is a very faint odor to humans, and as a species we can generally say humans have lost the ability to smell such a trace scent. Animals, however, still retain this ability. Sure, we can smell stagnant water, or water tainted with chemicals or sulfur - any kind of distinct odor, but water as a clean, pure, basic element has a smell that we cannot detect.
Animals use the variations in water "smell" to map the land they inhabit, too. Various water sources have different scents depending on what their organic composition is, and the inorganic solids suspended within it.
Photo courtesy of Azeem-Photos.Blogspot