By: Wendy Langhans
For those of you who remember the pre-cellphone era: have you ever scanned a crowd to find someone? Perhaps a friend you were supposed to meet. Perhaps a child who wandered away from your group? Can you remember how your eyes transitioned from a “wide area scan” to a narrow focus when you thought you’d found them? Well, it turns out that animals have this skill too. Not only can they focus their sight, they can also focus their nose.
To understand how this works, let’s begin with something we’re all familiar with – mucus – otherwise known as snot.
Mucus is produced by mucus membranes that “line the passageways inside our bodies that connect to the outside environment”. That includes the inside of the nose. Mucus is made up of “water, proteins including mucins (glycoproteins – proteins with attached carbohydrates), antibodies, and antiseptics, and salts.” As odorant molecules enter the nose and are absorbed by the mucus, they come in contact with the sensory receptors lining the epithelium. But not all odorant molecules are absorbed the same – some are more readily absorbed that others.
Scientists at the University of Chicago conducted experiments with rats to determine if the absorbant properties of odorant molecules affected how the rats sniffed. First, they trained “rats to detect a specific odor by rewarding them with a sugar pellet”. Then they attached electrodes to the rats’ diaphram to measure the rate at which they were taking in air”. Finally, they “tested the animals with many mixtures of two chemicals to see if they could pick out those containing the target scent.”
They “found that animals adjust their sense of smell through sniffing techniques that bring scents to receptors in different parts of the nose. The sniffing patterns changed according to what kind of substance the rats were attempting to detect.”
With low-absorbing odor molecules, the rats inhaled for a longer time until they learned to detect the odor. According to the researchers, “the air was moving through the nose at a slower rate and targeting those parts of the nasal epithelium that are further along in the pathway—those more likely to pick up the low-absorbent odors”.
But with high-absorbing odor molecules, the rats “inhaled more quickly because the parts of the nasal cavity that are sensitive to those smells are closer to the start of the nose’s air pathway.”
By adjusting how they sniffed, the rats were able to direct the odor molecules to the sensory receptors where they could best be detected.
In other words, they were able to focus their nose on the sweet spot so they could obtain the sweet treat.
Upcoming Outdoor Events:
Trail Maintenance Schedule. Come join our volunteers as they help maintain our trails. Contact Steve at firstname.lastname@example.org for time and place.
Wednesday mornings, November 7, 14, 21 & 28.
Saturday mornings, November 3 & 17.
Saturday, November 17, 8:00-10:00 AM. “Wild Birds of Autumn” at Towsley Canyon. The birds are busy preparing for winter. Beginning birders are welcome. Binoculars optional. Meet outside at the front gate. Click here for a map and directions.
Saturday, November 24, 3:00-5:00 PM. “Handy Plants of the Chaparral at East & Rice Canyon. Ancient uses of local plants are more popular than ever with today’s interest in health, the environment and holistic medicine. Learn how plants and herbs are used for traditional teas, food, medicine and more. Meet in the parking lot. Click here for a map and directions.
New trail maps available. If you’d like to explore a bit on your own, the City of Santa Clarita has a website with trail maps of our local open spaces: http://hikesantaclarita.com/.
There’s also a new website for bicycle riders. http://bikesantaclarita.com
You can listen to stories like this every Friday morning at 7:10 a.m. on “The SCV Outdoor Report”, brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.
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