Freka, the youngest Husky who lives across the street, goes out for her evening walk at the same time that I’m calling the cats in for their dinner.

Our neighbour is a friendly wolf, so when we meet, she’ll jump excitedly, and then I get a proper canine greeting: a quick lick of the hands, a friendly paw, and then she gooses me.

Yup, I get a long furry nose, right in the ooh la la.

The thing is, every dog tall enough to do this, does so. In the last week or so I’ve been goosed by a Doberman, a black Lab, and a tall fellow with an Alsatian type face and a Rottweiler bod.

Although it’s a little unsettling, it’s part of canine culture. When dogs meet each other, they’re very often face-to-face for a second, and then it’s mutual bottom-sniffing. I see it all the time, but I did get to wondering, what is that all about exactly? I mean, of all the parts to sniff, why pick that area? Isn’t it just too gross?

So I did some research and found out some fascinating facts.

How good is that nose?

It’s easy to see that dogs’ noses are far superior to ours. After all, we use Beagles and Bloodhounds to track quarry through forests and fields, something we humans couldn’t do even if we wanted to.

A very powerful tool.

A very powerful tool.

Exactly how superior canine noses are, though, is uncertain. The olfactory epithelium, a bit inside the nose that’s responsible for detecting scents, is lined with olfactory neurons, tiny hair-like structures that wave about, picking up signals. We humans have some 2 million to 5 million of those, whereas dogs have between 220 million and 2 billion.

How this all adds up is hotly disputed, with conservative estimates suggesting dogs can pick up a scent some 100 to 1,000 times better than us. It’s hard to get an idea of the size of a smell, but it makes sense if you think in terms of sight.

Basically, if we can spot a cat sitting 300m away, a dog could spot that kitty 30km to 300km away.

dog smell buttImpressive, right?

We have so much trust in Man’s Best Friend that we ask dogs to detect drugs, bombs, and contraband for us. There are even dogs who can sniff out cellphones. The Guinness Book Of Records lists Murphy, a British Springer Spaniel, as the first dog to work in a prison, sniffing out phones in prisons – and Murphy can tell even if you’ve wrapped it in plastic and hidden it in a wall!

Knowing this, it seems even weirder that dogs poke their noses in other doggy bottoms. I mean, wouldn’t the poop stink be a nightmare for a sensitive canine nose?

So it turns out that dog noses have this extra, second system called Jacobson’s Organ. This is basically a chemical analysis laboratory that makes those CSI departments on the telly look like amateurs.

Dogs can take one whiff of another dog’s bum, and get an instant mental printout of their friend’s health, diet and mental state. What’s more, this organ connects right to the brain, so that any smell of pooh doesn’t overwhelm the sniffer.

stop-sniffing-my-butt-you-pervAnd why does it have to be the bottom? Because it’s the site of anal sacs, little pouches that secrete loads of chemicals. Basically, the bottom part of the dog is the most prolific in terms of scent secretion.

It seems that lots of animals have this super detection and analysis system, including cats, snakes, pigs, horses, apes and lizards. Apparently turtles can do it underwater, too!

Training and dog greetings

When I thought it all over, something struck me. When Freka gooses me, her mum exclaims and tells her pet not to do so. I can see why – we humans sometimes feel afraid or uncomfortable being around dogs. Also, there are practical implications like muddy paws.

However, seeing that this kind of sniffing is a vital part of dog communication, I’m thinking there is a larger picture.

There is a tendency for us humans to look at pets and to judge them by our standards. Clearly this is problematic. For a dog, to properly say hello to another dog, to understand how their pal is feeling (emotionally and physically), is extremely important. They can’t do this by smiling at each other, or sniffing each other’s faces.

Therefore, it seems to me that we shouldn’t stop our pets smelling each other’s bottoms, even if it makes us go “Eeeeewww” inside.

Me, I always enjoy talking to my dog friends, and I don’t mind paws or noses. However, I must say that there’s an extra bit of awe now. The next time Freka gooses me, I’m going to be wondering exactly what her nose tells her about me.

Dogs are truly awesome.


When dogs have to choose between trusting their noses or their handlers

What’s curious is that dogs should trust their sense of nose, knowing that it’s superior to ours. However, when they work with us, dogs sometimes take their cue from us.

Scientists at the University of California got together 18 professional drug- and bomb-detecting teams. They told the human handlers they were conducting tests to see how effectively the dogs could identify which paper bags contained target scents and which didn’t.

dogs-708354_1280

However, when the tests were run, the scientists sometimes lied to the handlers, telling them an empty bag contained scent when it didn’t. They also tried to mislead the dogs by planting food in some of the bags.

As it turned out, the dogs were hard to fool. They could tell the difference between a bag with a treat and one with target scent. However, handlers who mistakenly thought bags contained target scents were sometimes influencing their dogs to flag these as “hot”.

It suggests that dogs sometimes trust us so much that they’re willing to take our word for something even when their noses tell them we’re wrong.

While the experiment was too small for robust data analysis, it’s something that we should look into. For one thing, it means handlers have to know that a dog at an airport or police raid may be picking up their human’s suspicion rather than an actual scent of drugs, bombs or other illegal substance.

Also, we are looking into using dogs to detect cancer and other health problems. As doctors and technicians will have opinions, and sometimes strong ones, we’re going to have to work out protocols to make sure these don’t influence research results.