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Good Question: How Strong Is A Dog's Sense Of Smell?

MINNEAPOLIS (WCCO) -- This week, St. Paul Police found a 3-year-old boy wandering around lost in his neighborhood. They called in a K-9, whose nose helped the toddler find his way back home.

So, how strong is a dog's sense of smell? Good Question.

We see better than dogs, but they crush us when it comes to smell.

"It's probably hard to pinpoint exactly how much better they smell," said Dr. Jennifer Hanson of Rockford Road Animal Hospital. "Because they can't tell us. They can't self-report. They can't tell us what they're smelling."

So how do we know that they can smell so well?

"We certainly have the evidence of the anatomy of how they're built," Dr. Hanson said.

Dogs have longer and more developed noses than humans.

"It's a much finer bone structure that's all covered with the membrane that senses smell," Dr. Hanson said.

Humans have 6 million scent receptors, but dogs can have 20 to 50 times that.

"It's like having a microphone as opposed to listening with the naked ear," Dr. Hanson said.

"If you can smell a Spritz of perfume in a small room, as dog would have no trouble smelling it in a small stadium," Dr. Hanson said. "Part of being more precise is that they don't get a general sense of odor the way me might -- they can break down the components of the smell."

That's why dogs can be so good at sniffing out bombs and drugs. The area of the brain that processes smells is much larger, relatively, in dogs than in humans.

"They can actually detect differences between what's coming into the left side of their nose and what's coming into the right side," Dr. Hanson said, "which is partly what helps them detect something and follow it in a certain pattern."

Some studies have shown dogs have been able to detect cancer by smelling breath or urine samples, but experts say more research needs to be done on this topic.

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