Can Dogs See in the Dark?

Have you ever wondered if your cherished canine companions are capable of seeing in the dark? 

According to veterinarians and veterinarian behaviorists, because of an evolutionary advantage and the unique structure of their eyes, dogs are extremely well equipped to deal with low-light conditions.

A dog’s vision works similarly to ours in that light enters the eye through the cornea, passes through the pupil, and is focused by the lens onto the retina at the back of the eye. But there are also some key differences in the way people and dogs see the world. The retina contains two types of photoreceptor cells: rods, which detect light and motion, and cones, which detect color and detail. Although dogs have a far higher concentration of rods than people do, they also have fewer cones. This means that dogs may be excellent at detecting movement and seeing in low light, but their color vision is limited to seeing mostly shades of violet, blue and yellow. 

Because a dog’s vision isn’t as refined as ours, they rely more on their other senses, such as scent and hearing, to navigate the world. And while 20/20 vision is considered ideal for people, a dog’s visual acuity, which is a measure of clarity, is about 20/75. What this means is that they will have a more difficult time seeing fine details. Dogs do, however, have a wider field of view than people do -- 240 to 270 degrees compared with a human’s 180 degrees. This means that dogs see more of their surroundings without moving their heads, which helps them stay more keenly aware of any possible threats and/or other activities.

Technically called scotopic vision, dogs do indeed have night vision, thanks to the physiology of their eyes. Like most other mammals, except for pigs and primates, their eyes have a reflective structure called the tapetum lucidum that sits just behind the retina. The tapetum lucidum reflects light back onto the photoreceptors of the retina, which doubles the amount of light that’s absorbed, allowing for much more sensitive vision in dark conditions.

Those extra rods mentioned earlier, which are also sensitive to dim light, permit dogs to see in a dark room, and the fact that they have larger pupils than humans, thereby allowing in more light, also enhances their night vision. 

Why then do dogs have night vision? It was a survival advantage from the hunting and scavenging behavior of their wild ancestors. Dogs are crepuscular animals, meaning that they’re most active at dawn and dusk. Good low-light vision helped them hunt prey, avoid predators and find food and nests. 

While our domesticated dogs don’t rely on those skills as their ancestors did, being able to see in low light helps them move around the house at night – all the better to find their water bowls at 3AM!