FURR YOUR INFORMATION— HOW DOGS SEE THE WORLD
Our last doggy blog gave some insight on the scent-sationals sniffing powers that dogs possess— recall that the section of a dog’s brain that is devoted to analyzing smells is 40 times larger than that of a human! This week, we’re looking at the way that dogs see the world around them.
My dog, Olive, gets anxious around the unknown. This anxiety often manifests itself in a high-pitched bark meant to challenge to mail carriers, visiting guests, or any passerby walking their dog too close to our home. When out for a walk, Olive often slows her pace and stares in the direction of any large object she encounters, seemingly trying to make heads or tails of whether it is a threat to her. As we pass trash cans, mailboxes, or bushes it is not unusual for us to slow our pace to allow Olive to find her bearings. Around two months after adopting Olive, we noticed that she needed to get very close to my partner and I before she could distinguish our identity. One day, after reassuring Olive that the large object she was defensively barking at was just a trash can, we realized that Olive’s eyesight might not be so great. After a quick google search, we discovered that most dogs have pretty bad eyesight.
The Structure of the Canine Eye
Word on the streets is that our canine companions can only see in black and white, but science has revealed this isn’t entirely true. A dogs’ vision is actually most similar to people with red-green color blindness. Where humans have three specialized receptors in their eyes to distinguish the colors red, yellow, and blue, dogs have just two. In dogs, the two-cone structure of their retina allows them to see only yellow and blue lights.
When a person has a defective third receptor, they are considered colorblind and are either unable to process reds and greens or blues and yellows. Like red-green colorblind humans, dogs cannot detect the colors red or green. So, when looking at a juicy red apple or a green lawn, your pup sees shades of grey instead.
Aside from the color issue, dogs’ tend to be nearsighted and lack depth perception, making what they see a blurry mess. In fact, studies have shown that dogs’ vision is somewhere around 20/75 compared to our ideal of 20/20. Human vision at 20/40 is so severe that it cannot be corrected with regular glasses, so even if your pup learned to control the steering wheel, peddle, and brakes someday, their extreme visual impairments would prevent them from ever getting a driver’s license.
Are you eager to discover what your pup sees when they walk through the world? Download the app Dog Vision and you can experience the world through their eyes.
Have you ever been in the dark with your dog and noticed the laser beam like glow in their eyes? That glow is called eyeshine, and it’s part of what gives dogs such incredible night vision. Although your pet might act like it wouldn’t hurt a fly, all dogs descended from natural predators. The ancestral wild canines that preceded domestic dogs were nocturnal hunters, hunting primarily during the hours of dusk and dawn. These canines needed to be able to spot movement in dim light in order to track and catch their prey. Like most predatory animals, they developed exceptional night vision.
The retina is a net of tissue that lines the inside of the eye and helps to form images from light input. Dog eyes have wider retinas than humans, which means they’re capable of processing even very small amounts of light.
Like cats and other wild mammals, the canine eye has a larger pupil than the humans do, making navigation in the dark much easier. However, for dogs, the secret to night vision rests in the part of the canine eye called the tapetum lucid- a layer of tissue between the retina and optic nerve that increases the amount of visible light available to the photoreceptors and acts like a mirror. The tapetum reflects back the light that enters it, giving the retina another opportunity to register the light. So, dogs can see in the dark, and other low-light situations, better than humans.
So, whether your dogs is anxious and protective like Olive or entirely docile, keep in mind that you and your dog see the world from entirely different lenses.
Dog lovers rejoice! This coming March, the California Science Center is opening an exhibit just for you, and it is guaranteed to be a tail-wagging good time! Dogs- A Science Tail is a new exhibit that is sure to excite your senses! Interactive displays like giant dog ears and a gallery of undisclosed scents will allow visitors to hear, see, and smell like a dog!
Through engaging and fun hands-on exhibits, explore the science behind the bond between humans and dogs. Find out how humans and dogs are both wired for social connection, which made it possible for dogs to nuzzle their way into human society and into our hearts. Discover dogs’ amazing senses and grab the chance to see, hear, smell, run and even think like a dog. And don’t miss the live demonstrations of working dogs, rescue dogs and therapy dogs in action!- California Science Center
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