Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren Vogel Bomb. Here, we humans have done pretty well for ourselves evolutionarily speaking, with our winning combo of dexterity, intellect, endurance and a scrappy can do attitude. But although humans are physiologically tricked out in a lot of ways, other animals have evolved capabilities that we don't have,
sniffing out water sources, for example. That ability seems like it would have been of great evolutionary advantage to us, considering that relative to most other animals, humans have exceptionally high water intake requirements, and so if dogs, elephants, and vultures seem to be able to smell water, why can't we? Before we get too far down this rabbit hole, let's be clear about two things. First, science has always characterized
the human olfactory senses being just so. So, though recent research suggests that we might be able to differentiate between around a trillion different odors, modern humans don't interface with the world through our shnaz is as much as some other animals do. Also, water is odorless. This chemical element is a total non negotiable requirement for almost every organism on Earth. But it's just a couple of hydrogen atoms stuck with covalent bonds onto an oxygen atom. There's nothing
smelly going on there. So it seems that American environmentalist Edward Abbey was onto something when he wrote in his memoir Desert Solitaire, a season in the Wilderness in quote long enough in the desert, a man, like other animals, can learn to smell water, can learn at least the smell of things associated with water. The unique and heartening odor of the cottonwood tree, for example, which in the
canyon lands is the tree of life. Because although plane H two has no scent, chemically pure water are also basically never occurs in nature. You've got to make that stuff in a lab. So when other animals sniff out a water source, it isn't the water itself they're smelling. It might be a water loving cottonwood tree, or other stuff in or around or otherwise associated with the presence of fresh water, chemicals, bacteria, algae, plant matter, or minerals.
For the article, this episode is based on How Stuff Work. Spoke with Dr Kara Hoover, and anthropology professor at the University of Alaska, Fairbanks. Doctor Hoover specializes in the evolution of human smell. She said, humans, like all terrestrial animals,
smell volatile or airborne compounds. Our class one olfactory receptor genes that detect water born odors are switched off, so we can smell water via other compounds in it that get released into the air through a variety of physical processes.
According to Hoover, people have evolved to take pretty detailed visual and auditory inventor worries of their surroundings, and though our olfactory assessments aren't often as thorough as those of some other animals, we are perfectly capable of detecting a nearby swimming pool when we smell chlorine, and we can pick up on the sulfuric odor of a hot spring, or that mineral rich dead fish thing that the ocean's
got going on. Like Edward Abbey said, we might be able to teach ourselves to detect water sources if we applied ourselves to learning the smells that go along with it. Another reason humans don't smell sources of water as well as other animals maybe precisely because we need a lot of it. Our bodies require extravagant amounts of the stuff due to the way that we sweat. According to Hoover, walking exclusively on two feet came with some physiological shifts
that drastically raised our water requirements. Hooever said, one major shift is our ratio of echerne to apocrine glands. Modern humans have more echerne glands than any other mammal. These glands release water and to a lesser extent, sodium from our bodies when we sweat a Shedding water through ecrine glands is less energetically costly than shedding nutrients through apocrine glands, which is why humans will always beat a horse in a long distance race as long as there's water available.
Hoover suggests that between four and seven million years ago, when our ancestors became bipetle, they became tied to sources of water, meaning they couldn't afford to sniff around. They needed to know where to find reliable sources of water in their home territories or long regularly traveled roots. Hoover said, but we have no way of knowing, but most likely our original home ranges included water sources that were cognitively mapped.
As ranges expanded and new sources would be located, and maybe that next watering hole could be found by just following an elephant around for a while. Who needs a good nose when you've got brains. Today's episode is based on the article why didn't evolution give us the ability to smell fresh water? On house toff works dot com
written by Jesslyn Shields. The brain Stuff is production of Our Heart Radio and partnership with hous toff works dot com, and it's produced by Tyler Playing the four more podcasts from my Heart Radio visit the i Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.