Friday, 17 November 2017

How Our Five Senses Compare To Those Of A Dog

Our dogs may be deprived of common sense, but when it comes to the 5 senses, we should be in awe and understandably envious, with a couple of exceptions.  We have a better sense of taste, possessing about 6 times as many receptor cells on our tongues as do dogs. If they had as many taste buds as we do, they wouldn’t (you finish the sentence).

I’d also rather have my eyesight than a dog’s. They see better in dim light and hold a slight advantage over us when it comes to seeing beside and behind them, but their color perception is weak.  I’ve seen their color vision likened to our color vision at dusk. A dog’s eyes are 90 per cent rods, and you’ll remember from primary grade science that it’s the cones that provide color perception.

A dog’s hearing is better than ours, though. Not only is the frequency range of sounds they can hear wider than ours, but dogs with upright outer ears are able to funnel fainter sounds into their hearing mechanisms.

The outer ear, besides acting sort of like a satellite dish, is also capable of independent motion (floppy-eared dogs are disadvantaged here). By rotating the ears, dogs are better able to determine where a sound is coming from.

The main difference between a dog’s sense of touch and that of a human is the fact that they have specialized hairs (back on the block we just called them vibrissae) on their muzzles, eyebrows and lower jaws.

These stiff hairs, which are embedded deeper than other hairs, can detect air currents, subtle vibrations, and objects in the dark. It’s possible that they also direct food and other objects to the mouth. I think some of us old human males have these hairs in our ears.

Saving the best for last, there’s no comparing a dog’s sense of smell to that of the lowly Homo sapiens. Heck, a dog can detect butyric acid, a component of sweat, from 1 million to 100 million times better than we can. Jealous?

In humans, the area of olfactory receptor cells that communicate to the brain covers about 1 square inch. In a dog, depending on the length of its muzzle, that area can be up to 60 square inches. And here’s where those “hearing compromised” floppy-eared dogs make up for it.

Those floppy ears allow for more scent to be directed to the nose. What’s more, dogs and other non-human mammals possess a functioning vomeronasal organ (VNO) also known as Jacobson’s organ. We have one, but it doesn’t work anymore.

The VNO’s specialized receptor cells detect pheromones, which are abundant in dog pee and poop, providing a lot of information, including another’s social status and reproductive state.

You’ll see an interesting behavior in dogs, known as tonguing. They’ll click their tongue against the roof of the mouth, the teeth may chatter and there may be a little foam on the top lip. They’re directing molecules of scent to the VNO.

Dogs lift their legs to deposit their urine high up on vertical surfaces so that the scent can be better carried by air currents to the VNOs of others, and also to prevent those yippy little lap dogs from over-peeing the spot.  

Bob Bamberg has been in the pet supply industry for more than a quarter century, including owning his own feed and grain store in Southeastern Massachusetts, USA.  He writes a weekly newspaper column on pet health, nutrition and behavior and his articles appear at

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