Why Some Animals See at Night, But You Can’t


It doesn’t seem fair. Aside from rough outlines in the distance, humans really can’t make much out in the darkness. Your canine companions and feline friends, however, can. But why is that? Why can some animals see in the dark and we can’t. The question isn’t as simple as visiting an ophthalmologist and getting your vision adjusted for the dark.


Here is just a glimpse at the unique and very interesting difference in our eyes, versus, say, those of your family dog.


Different Eye Types


There’s a big difference in animals’ eyes and ours. Did you know that in the animal kingdom there are over 10 different eye types? Each eye type is catered to the particular species, with regards to its environment and needs. A raccoon, for instance, is nocturnal. So it has large, reflective eyes with large pupils designed to gather as much light as possible, making it ideal to forage in the darkness.  Similarly, dogs evolved as nighttime hunters, so their eyes serve a common purpose.


Humans have camera type eyes that are designed for an array of uses, but lacking the specialty of night vision, like a raccoon or a dog. But more on the differences between our eyes and your dog’s eyes below.


Rods and Cones


Rods and cones are the key players in our ability to perceive color and light. Humans have three types of cone cells, and a multitude of them—about 95 million, actually—giving us the ability to perceive and differentiate colors. When it comes to seeing in the dark, however, not so much.


Dogs and cats have more rod cells in their eyes and only two types of cone cells. These rod cells are great at perceiving things in low light situations. However, rod cells aren’t designed to perceive all colors on the spectrum. Interestingly enough, a dog’s eyes have been compared to those of color blind people, who also lack the third type of cone necessary to perceive all colors.


The Tapetum


Dogs and cats are equipped with an additional piece of night vision software called the tapetum. This reflective layer positioned under the retina amplifies vision in low light situations. This mirror-like component is also why the eyes of certain animals shine in the dark when light is reflected off of them; their eyes are merely reacting to light as they were designed to.


For More Interesting Facts


Sight is a valuable tool for animals and humans alike. Ensuring your sight is up-to-par is important. If you are interested in learning more about options for your own eyesight, contact Dr. Ghosheh at Advanced Eye Medical today and set up an appointment.