Dogs are renowned for their ability to identify and track objects by scent…
Now it’s been revealed they enhance this talent with special brain structures that link it to how they see.
A study published this month in the Journal of Neuroscience revealed that vision and the sense of smell are connected in the brains of dogs, something not yet found in any other species.
“The most interesting thing about this research are the connections from the nose up to the occipital lobe, which houses the visual cortex,” said veterinary neurologist Philippa Johnson, an associate professor at Cornell University’s College of Veterinary Medicine and senior author of the study.
The discovery suggests smell and vision in dogs are integrated in some way, although it’s not known how dogs experience the two senses functioning together.
“Scent contributes to the visual cortex in dogs, but a dog’s experience is hard for us to know,” Johnson said. “But I think they can use scent to work out where things are.”
She explained that when humans walk into a room, they primarily use their sense of vision to establish who is there or how furniture is positioned. But dogs seem to integrate scent into their interpretation of their environment and how they are orientated in it, she said.
That’s borne out by the behavior of dogs that have lost their vision but don’t seem greatly affected by the fact that they have gone blind.
The sense of smell in dogs is known to be much more sensitive than in humans: the olfactory bulb in a dog’s brain is about 30 times larger than in a human brain. Dogs have up to a billion smell receptors in their noses, compared to just 5 million smell receptors in people, Johnson said.
But the discovery suggests the sense of smell is much more vital to dogs than previously thought.