WHERE’S THE WATER?
Dear HIW,
Some animals seem to be able to sense their way to water. How? Also, why can’t humans do this?
Stephen
Different animals’ senses vary significantly, but many have evolved to be able to find water, as it’s essential for most living creatures. Some animals can smell water sources from many miles away. The water itself is odourless, but it reacts with the plants, bacteria, chemicals and minerals surrounding it. By learning the smells of the soil and plants associated with water sources, animals can follow their nose to moisture. Evidence suggests that larger mammals are more likely to remember the location of water sources and return to the same ones. This includes humans. Scientists think that when we began to walk on two feet, our water requirements increased. At this stage in our evolution, humans developed more eccrine glands. We began to lose more water than other mammals through sweating and needed to be based near reliable water sources for survival. During this transition, modern humans no longer needed to be able to smell water sources.