A dog’s life begins with his nose

DAWSON CITY Rover can’t see red. But he might be able to smell cancer. It’s a different world for dogs, said University of British…


Rover can’t see red.

But he might be able to smell cancer.

It’s a different world for dogs, said University of British Columbia psychology professor Stanley Coren, talking to a crowd in Dawson City on Saturday.

“What’s in a dog’s head comes from what’s going on in his senses,” he said.

Coren is a dog psychologist. But he wasn’t travelling with a fur-covered couch taking pooch patients.

 Instead, he had a portable speaker playing a tinny instrumental version of You Ain’t Nothing But A Hound Dog.

Sporting a long scarf held tightly at the neck by a silver ring, the portly professor got into the nitty gritty science of canine senses right off the bat.

Starting with how dogs see, he broke down the eye by using charts and getting into details that included things like nictitating membranes.

But the gist of it was, dogs need glasses.

They wouldn’t be able to drive without them, said Coren with a chuckle.

Because they’re designed to hunt at night, dogs have more rods, giving them better light sensitivity. But the tradeoff is fewer cones, making their visual acuity poor.

And although they have better peripheral vision than people, they have less binocular vision, where both eyes are picking up the same image.

Dogs have 20/60 vision, said Coren. So, what a normal person sees at 60 feet dogs can only see at 20 feet.

Figuring out how well a dog can see is no easy task, he added.

“They don’t read eye charts.”

To determine their acuity, dogs were trained to pick out subtle grey lines from groups of mostly grey charts.

When a dog could no longer distinguish the lines from the plain grey paper, their vision could be calculated.

Researchers did a similar experiment with colours.

And while dogs don’t just see in black and white, their perception of colour is limited.

“They see mostly in yellows, browns and greens,” said Coren.

“So when you throw that bright red dog toy and your dog runs right by it in the grass, he’s not actually being stupid and obstinate — he just can’t see it.”

Dogs rely mostly on motion perception to compensate for their fuzzy vision, he said.

After dispelling the myth that dogs don’t see in colour, Coren moved on to their hearing.

“Most people think dogs have better hearing,” he said.

“But that is only partly true.”

For the human speech range, dogs and people have almost identical hearing, he said. Only humans can hear even lower sounds than dogs.

“So the idea you don’t have to talk as loudly to dogs is nonsense,” he said.

However, dogs have an advantage when it comes to high notes.

The highest note a human could hear would be to extend the upper notes on a piano by 28 keys. But dogs would hear up to 52 more keys, he said.

The higher frequencies allow dogs to hear rustling in the bush, to help with hunting.

Just like humans, dogs are susceptible to hearing loss as they age, said Coren. And some breeds, like Dalmatians, are more prone to deafness than others.

People used to think hunting dogs were more susceptible, but eventually realized it was just that these dogs were often in front of firearms going off.

A dog riding in the back of a truck, or with its head out the window, will start to have permanent hearing loss after about half an hour, he added.

A dog’s best sense is smell.

“They identify things by scent first, hearing next and use vision to confirm it,” said Coren.

A dog’s ability to smell is one thousand times better than a human’s, he said.

And bloodhounds are at the top of the list, followed by beagles.

Capitalizing on this heightened sense, dogs are used to detect arson, sniff out drugs, termites, dead bodies, and even determine cows’ menstrual cycles.

“There’s only a brief window where cows can be bred,” said Coren.

So, a farm in BC trained a dog to walk along sniffing the behind of cows and signaling when they are menstruating.

“Dogs can also sniff out leaks in pipelines 40 feet underground.”

And they are beginning to experiment with dogs detecting melanoma and prostate cancer, said Coren.

In the early 1970s, Agriculture Canada was experimenting with dogs sniffing out illegal agricultural products at airports.

They were using labs in the tests, and Coren suggested they use beagles instead since that breed has a better sense of smell.

“But they were worried people would laugh at the beagles,” he said.

Eventually, Coren convinced them to give it a try and gave them two rescued beagles.

It took only two-and-a-half months to train them, instead of the seven months it took the labs, he said.

And the beagles now have their own little green coats with the Ag Canada logo attached.

Coren, who wrote a book about the intelligence of dogs, went down the list at the end of his lecture.

The smartest dogs are border collies, followed by poodles, then German shepherds and golden retrievers. Labs come in seventh, after Dobermans and sheep dogs.

The caboose is afghan hounds, with the basset and the beagle not far above.

But Coren opted for a beagle.

“I needed a dog that was friendly and that would forget my granddaughter had just pulled its tail five minutes before,” he said with a laugh.

“And my dog carries out those tasks well.”

Coren came north as part of the Yukon Science Institute lecture series.