3. Dogs can wiggle their nostrils independently, which helps them figure out which direction a scent is coming from. Humans can only wiggle their nostrils simultaneously. (Try it. We’ll wait.)

4. Dogs are great at interpreting all the information coming in through their noses in fine detail. In her book “Inside of a Dog,” canine cognition researcher Alexandra Horowitz writes that humans might taste a teaspoon of sugar added to a cup of coffee. But a dog could detect the same teaspoon of sugar in a million gallons of water—enough to fill two Olympic-sized pools.

And to take the sugar metaphor further, “if we humans walk into a bakery, we can say, ‘someone’s baking a pie in here,’” canine search specialist Lynne Engelbert told NOVA. “A dog would walk in and say, ‘Oh, someone’s baking a pie in here, and it has apples, and butter, and cinnamon, and nutmeg.”

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5. Dogs can connect a human with the scent they leave behind with exceptional precision—and even help diagnose sick humans with a variety of diseases. Forensic chemist Ken Furton, who has studied dog olfaction for more than 25 years, once blew up a car with colleagues and then asked detection dogs to pick out human scent from the resulting debris. The dogs were able to sniff the small amount of shrapnel and correctly identify the people who had been in contact with the bomb pre-explosion 82% of the time.

More recently, Furton and his colleagues looked at whether dogs might be trained to identify COVID-19 patients—and found they could do so with 97.5% accuracy. “I was shocked,” he told NOVA. And one 2019 study indicated humans’ best friends can sniff out cancer with a similarly high 97% accuracy rate.

Watch: Cannabis-Sniffing K-9's: Out of a Job?

6. Dogs can not only identify human remains–they can sniff out already cremated remains from among other ashes. Dogs in the American West are now being trained to look for the cremated remains of homeowners’ loved ones when those homes are lost to the region's increasingly fierce wildfires. The non-profit Alta Heritage Foundation brings specially trained search dogs and archaeologists to the site of a house destroyed by fire, using canine colleagues to narrow down where the lost ashes might be buried and then archeological techniques to excavate them. 

The ashes are often the only thing his clients want to recover from their houses, Alta Heritage founder Alex DeGeorgey told NOVA. So being able to find their loved ones’ ashes within the ashes of a house is both powerful and continually surprising. “I’ve done this hundreds of times,” DeGeorgey says of cremation ash recovery, “and I still marvel that we’re able to do it.”

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