By Sarah Hatfield
Water falls toward soil. And in the act of kissing of the earth there is an exhalation. Geosmin is released as the water droplet breaks the earth’s surface, and into the air is released a scent. Petrichor. This is the smell of rain.
In one of my favorite magazines I discovered that word, petrichor. The smell of rain. All people know that smell. Perhaps it arrives before the rain, but always just after and stronger with light rains rather than storms. It is that musty, but not quite, smell. It is dampness and dirt and water and cloudiness. I was curious so I looked it up.
It turns out that this smell is so distinct that in 1964 two researchers gave it a name. In a short version, plants release a substance in dry weather that sticks to soil and stone. When raindrops hit the soil and stone after this dry period, the force actually causes the particles to aerosolize and then we smell them. Petra comes from the Greek word for stone. Ichor comes from the Greek word that means “from the blood of the gods.” A smell born of the earth and released by the heavens.
I have walked outside tilted my head to the sky and inhaled. “Smells like rain.” From miles away, riding breezes and dancing through fields, forests, and city streets, petrichor wafts toward me. In some areas, at some times, the smell is intoxicating, causing cattle to walk in circles of anticipation of the coming rain. I have stood out on the sidewalk, arms wide, waiting for the raindrops to follow the scent. Maybe it is the aroma of relief – drought stricken areas and those waiting for seasonal rains crave it.
But why does it smell? What is the purpose of the scent? Probably nothing, although I suppose that it could be meaningful in a way that we humans have yet to understand. A secret conversation that we cannot translate.
Other scents do have a purpose. Some aromas beckon, beg, and bribe. Flowers release scents as signals. They let any pollinator in the area know that there is a sweet and delicious reward for the first to arrive and get the job done. Rose, lavender, jasmine – they are heady smells. Interesting, perhaps ironic, that some people also use them, perhaps trying to attract their own audience?
Other scents that constantly barrage our nasal passages are pheromones. These scents are used to communicate within species. One species pheromone is just an odor outside that species. They are subtle. So much so that we can’t even consciously detect our own human pheromones! Yet within a species the messages can be potent, and unconsciously the message gets through.
Pheromones can protect an animal, and bring an army to its defense. They can also shout “this is mine!” Those message scents allow baby animals find their mothers in herds, identify friend from foe, and lead families to food sources. Perhaps the most basic purpose of pheromones is to attract a mate. The female moths that emerge from cocoons at Audubon Nature Center are placed in a cage. When the females release their mating pheromones, males come from miles away and flutter around the cage, mating through the screen. As a side note, we do let many go, but keep some in the cage to raise the caterpillars to ensure their survival.
Whether signals, pheromones, or simple odors, the world is full of fragrances. In reading about petrichor, I thought about the other scent that is distinct and exceptional that I only find in nature. It is the smell of clothes hung on a line to dry in the sunshine. The same smell lingers on my skin after I’ve worked out in the sun, especially in the crook of my elbow or the back of my hands. I have looked and there doesn’t seem to be a word for that smell. It is the scent of work and fresh air and open spaces. It sticks to the sheets and the towels and at the end of the day there is nothing like crawling under sunshine sheets.
Scent evokes stronger and more memories than sight or sound. Occasionally I smell something and I connect with the scent. Did I smell that as a child? Did it connect with a memory, a lesson, and experience that I have long since forgotten, but the synapses in my brain can still recall? Is it woven into my genetic makeup from long ago? Perhaps this is why people have favorite scents – their great-great-great-great-great grandmother was an herbalist and found the herbs she needed by scent and so that somehow was passed through the years. That sounds mostly foolish and yet…
Whatever the reason – for message or just because – scents enhance our experiences, especially when outdoors. It allows us to connect with the world in another way, one that seems to imprint itself on our brains. The smell of sunshine doesn’t have a name, but maybe someday it will. In the meantime, head outside during a light rain after a few dry days and breathe in the petrichor. Find more beauty in the moment knowing that there is a conversation happening between air and earth and water that we will never truly understand.
Sarah Hatfield is senior naturalist at Audubon Nature Center. The Nature Center is a good place to walk in the rain. Not only scents, but sounds and sightings will envelop you. The trails are always open dawn to dusk. The Nature Center building is open from 10:00am until 4:30pm daily, except Sundays when we open at 1:00pm. We are located at 1600 Riverside Road, just off Route 62 between Warren and Jamestown. Call (716) 569-2345 for more information or visit our website http://jamestownaudubon.org.