Animals sniff the air and ground to track the source of a scent

Anyone who watches a dog in the park will notice that sometimes the pup will stick her nose in the air, and other times, she will excitedly sniff the ground. Until now, scientists have not been able to figure out why animals decide to sniff the air versus the ground. An international team of researchers is shedding some new light on the topic.

“We used what we know about how scent is carried by the wind and on the ground to understand better why animals engage in this behaviour,” explained study co-lead author Nicola Rigolli. “We then used machine learning techniques to identify the optimal strategy for locating the source of a scent.” 

The researchers created computer simulations to determine how scents move under turbulent conditions. Then, they modeled the advantages and disadvantages of sniffing the air versus sniffing the ground. 

The experts created a computer-simulated animal designed to minimize tracking time. They noticed that, like real animals, it would often go back and forth, sometimes sniffing the air, other times sniffing the ground. 

The researchers found that when an animal is downwind from a scent source, they stick their noses up frequently to catch a whiff. As they get closer to the source, they will begin to sniff the air less and the ground more. 

“Airborne scents are sparse and more difficult to track than scents along the ground, but they move faster and over longer distances. The benefits of sniffing near the ground or in the air therefore vary depending on the animal’s distance from the scent’s source,” explained study co-lead author Gautam Reddy. 

The researchers noted that the results might also be relevant to sea creatures, including crabs and mollusks. While the findings may not apply to real-world situations, the study authors expect that further research will yield more practical results. 

“We hope our results inspire other scientists to conduct experiments with dogs, rodents and aquatic animals that can help us learn more about these behaviours in real-world settings,” concluded study senior author Massimo Vergassola.

The study is published in the journal eLife. 

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By Erin Moody , Earth.com Staff Writer