I was once curious to know whether turtles can see in the dark. My curiosity came about when I saw my turtle walking around their aquarium with lights off. He did it so confidently that I was just amazed. I had to satisfy my curiosity, so I looked into it. I began my research to learn about turtles’ night vision. Here is what I found out.
Can Turtles See In The Dark?
Can turtles see in the dark? Yes, turtles can see in the dark. Their vision is no different from humans’ vision. If you happened to stay in the dark for some time, you would begin to see things. The eyes will have adjusted to the situation, and the iris will be wide enough to take advantage of the little light that comes into the eye. This is the same case with a turtles’ eyes.
Turtles vs Human Eyes
Although turtles’ eyes are just like human eyes, there are some slight differences. From the sources I went through, I noticed that turtles see more reds than the human eyes can. To elaborate more on this, let’s look at how turtles see colors. Do not forget to check out our post on how to look after a turtle.
How Do Turtles See Colors?
According to most people, Turtles are considered to be color blind. What people don’t know is that they have an additional ability to see one more extra color. Humans are unable to see this color due to some reasons I will talk about later on. This color is known as red. Human eyes are made to perceive three wavelengths of light which are red, green and blue. A mixture of the three wavelengths produces millions of colors. Can you imagine how many more colors a turtle can see with the addition of that extra color in the three wavelengths? Since the colors are a lot, it is the reason a turtle can see more colors compared to humans. I know it is contradicting when I say humans don’t see the red while at the same time red is among the wavelengths they can perceive. What I mean is that the turtle can see more shades of red.
Gene called CYP2J19
Scientists believe that turtles and birds have that extra cone that can perceive the red color better than human eyes. The reason is that the birds and turtles have a gene called CYP2J19. This gene is traced from a dinosaur over 250 million years ago. The creature had a birds head, turtles stomach, crocodiles body, and a pigs snout. The only was believed to be bright red. The turtles and birds got their extra ability to view more shades of red from the archosaur. While human eyes can see crimson and scarlet, animals with the gene perceive the colors in between.
Now that we know that turtles can see more colors than we can. It is time to understand how turtles see in the dark.
How Do Turtles See In The Dark?
Just like I said earlier, the turtles’ vision is the same as the humans’ vision with only some slight difference. Let’s take an instance where you just switched off the lights, and the room is dark, The turtle will not be able to see anything at that moment. He will have to wait until the iris adjusts to allow more light into the eye. After the eye has done the adjustments, the turtle will then be able to see things although not as clear. This is the reason why I found my turtle walking around his tank as if he was able to see in the dark. In the night also, things will have a red hue when looked at by a turtle compared to a human eye. These are some of the differences between a turtles vision and a humans vision.
How Do We Know That Turtles Don’t See In The Dark?
Animals that can see in the dark make use of the tapetum lucidum for their night vision. The tapetum lucidum is a retroreflector found just behind the retina. Its function is to reflect the visible light to increase the photoreceptors. It reflects the light through the retina and in layman’s language, it acts similarly to the mirror. There are specific animals that have tapetum lucidum such as the dog. Turtles do not have it; hence they cannot see in the dark.
Can you prove it?
To prove that a turtle does not have the tapetum lucidum, you can get a dog at night and take a picture of the dogs’ eyes with the flashlight on or shine light into the dogs’ eyes then take the picture. You will see that it is as if the dogs’ eyes are glowing. If you do the same with the turtles’ eyes, the results will be different. The eyes will not glow. This shows that the turtles do not have the tapetum lucidum. This is proof that the turtles’ eyes are just the same as the humans’ eyes.
How Turtles See Underwater?
It is difficult for human beings to see underwater. Even when you can see underwater, you will not be able to do it for long, and you will only be able to see short distances. On the other hand, the case is different for the turtles. They can see in water for a longer time and far underwater. The reason for this is that turtles live in water and hence their bodies have adapted to those situations. By adaptation, their eyes produce tears that cover their eyes.
Turtles Vision Underwater
This liquid prevents their eyes from being affected by the salt in the sea and the bacterias. The fluid also helps them to see in the water. This liquid is what makes the difference between a human’s vision in the water and a turtles vision underwater. Just like on land, in water, the turtle will see in the same way, same clarity and corresponding colors. The only hindrance to their vision in water is if the water is dirty and not clear. This will make them struggle to see. No one can see through the water. Other than that, a turtles’ vision underwater is just like the turtles’ vision on land.
Should I Live The Lights On For My Pet Turtle During The Night?
Unless you want to keep an eye on your turtle, It is not must you leave the lights on during the night. The turtle will be able to move around the tank safely. I would recommend ensuring that there is light during the day.
How Long Should You Leave A Light On For A Turtle?
This depends on the time of the season. In the winter, most of the time, it is going to be dark. You will, therefore, be required to leave the light on for those few hours when there is light. This should be for around 10-14hours. On the regular days, leave the lights on until it is dark outside. Only when the sun is up.
Can Turtles See Humans?
Turtles see humans clearly. They are even able to distinguish between people. Their eyes are similar to the humans’ eyes only that they can see more shades of red. They will, therefore, see humans with a reddish hue, but that does not hinder them from seeing the humans.