Eyes are the window to the soul, and that’s no truer than when your pooch is sat giving you the puppy eyes. Although dogs definitely see the world differently to us humans in a metaphorical sense, they see differently in a physical sense too. For a start, their vision isn't as clear as ours, and they can’t see as many colours as we do. But can dogs see in the dark differently?
We’re going to take a look at whether or not dogs can see in the dark, and see if your pup has the power of night vision.
Dogs can see in the dark, but they don’t exactly have night vision. If it’s completely dark, with no light at all, your dog won’t be able to see a thing, and neither would you!
However, most of the time when it’s “dark”, there are actually some sources of light around, whether that’s the moon, streetlights, or even the LED of your TV on standby. They might not seem like much, but once the eye adapts to these low-light levels you can see a surprising amount using these small sources.
Dogs have evolved to see clearly in dim light, so they have special adaptations that allow them to make the most of these very low levels of light to see movement and objects around them. However, if there’s absolutely no light at all, then your dog won’t be able to see.
A dog’s eye and a human eye are pretty similar in how they are formed and the way they work.
When you or your pup are looking around the world, light travels into your eye through the clear lens at the front, and then through your pupil. The pupil dilates or constricts to control how much light can enter the eye. The first super adaptation your dog has to help them see in the dark is a larger pupil, which means they can let much more light into their eyes.
Once light is in the eye, it lands on special photoreceptors on the retina at the back of the eyes. The photoreceptors in the retina turn this light into electrical signals, which the brain unscrambles and transforms into pictures.
There are two different kinds of receptors in a dog or human eye. These are called rods and cones. Rods help to detect light and movement, while cones detect colour.
A dog only has two cones in their eye, while a human has three, which is why dogs can’t see as many colours as humans. However, dogs have far more rods in their eyes than we do, so dogs can detect more light than we can.
That’s not all though, your dog has another secret weapon to make seeing in the dark much easier.
Have you ever looked up in the evening to see your dog staring at you with the glowing green or red eyes of a hellhound? Well, they’re not a monster in hiding, they just have built-in reflectors in their eye.
Dogs have a layer of tissue behind their retina called the “tapetum lucidum”. This special tissue acts like a mirror and it reflects light back onto the retina. This increases the amount of light their photoreceptors can use and gives your dog a second-chance to use the light that’s coming into their eyes.
So when your dog has eerie glowing eyes in the dark, or in photos, it’s because their eyes are actually reflecting the light back out!
Dogs don’t have night vision because they still require some light to be able to see.
The way that dogs see in the dark is nothing like if we used night vision goggles either, because night vision goggles detect infrared light to see. Your pooch can’t detect infrared light and still needs some visible light to be able to see in the dark.
However, pooches need a lot less light to be able to see compared to us humans, thanks to their specially evolved eyes. So to us it might seem like they have night vision, when really they’re just using light we can’t see.
We tend to think of most animals as either nocturnal, which means they’re active at night, or diurnal and active in the day. However, this isn’t always the case.
Wild canines are crepuscular creatures, which means they are most active at dawn or dusk. During these times of day, there is much less light, so it’s neither the bright light of day, nor is it complete darkness.
Dogs and other canines have evolved to be able to see best during dawn and dusk because those are the times when their prey animals, like deer, were most active. Being able to detect movement and see in low light meant they could hunt for their dinner easier, especially when their sight was combined with their super-powered senses of smell and hearing.
Even though our dogs don’t need to hunt deer at dawn anymore, they can still see in the dark because those evolutionary advantages haven’t gone away, even though our pooches have adapted to be active in the daytime alongside their humans. Luckily, dogs can see well in daylight and brighter light too, so switching to a human routine doesn’t seem to have bothered them too much!
We aren’t sure exactly how well a dog can see in the dark, but we know that they can see pretty well. They’re definitely better at seeing in the dark than we humans are!
Neither humans or dogs can see in complete darkness, because both you and your pup require some light for your vision to work.
However, in a low light environment, dogs can see in the dark far better than humans. Our pooches can see in the dark about 5x better than we can, because their vision will work with as little as 1/5th of the light we humans need in order to see.
The reason your dog is so much better at spying at night is because their eyes are adapted to make the most of low light. They have more rods in their retinas, so they’re more sensitive to light. They also have larger pupils than we do, which lets more light in. And finally, they have that incredible tapetum lucidum to reflect light and give them a second chance to use it. We humans don’t have a tapetum lucidum at all. (Instead, our eyes glow red in photos because the flash is reflecting off our blood vessels!)
All these nifty adaptations mean your dog is way better at seeing in the dark than you are. This means that your pooch doesn’t have to worry about smacking their shins on the coffee table when they’re walking around the living room at night!
Your dog might be better at navigating the night than you are, but our mutts aren’t as good as our moggies at seeing in the dark.
Scientists don’t know exactly how much better cats can see in the dark compared to dogs, but the current estimate is that cats can see using 1/6th of the light a human needs to see, while a dog can see with 1/5th. That means cats beat dogs, but not by much!
Cats are crepuscular animals too and have many of the same special adaptations to see in the dark as dogs. That includes those reflective cat’s eyes, which actually gave the inspiration for their reflective namesake used on the roads.