Have you ever wondered how a turtle’s eyesight compares to you, a human being? Do you want to know if turtles have a favorite color? Since turtles live underwater, is their eyesight different from ours? In this post, I am going to evaluate all of these questions and hopefully shed some light on the benefits of turtle’s evolutionary vision adaptations.
How do turtles see?
Firstly, turtles have eyes that are very similar and yet quite different from the human eye. One key difference is that their color pallet includes extra shades of red. This fascinating fact is due to a gene that is unique to certain species. They also have the capability to see clearly and with great distance underwater, which is not a trait that humans possess. Additionally, turtles have adapted for many years to be able to see better in the dark.
Anyone that owns a turtle has probably been able to observe their turtle making its way around the tank with little to no light. And yet somehow, the turtle appears to be doing so without any trouble. How is it possible?
Can turtles see in the dark?
While turtles don’t have laser sharp vision in the dark, they are able to maneuver around and see most objects around them.
Turtles do not possess the tapetum lucidum that dogs and cats possess, a characteristic that replicates the effects of a mirror and uses small amounts of light to expand the iris and process more in the dark. In this sense, turtles are more similar to humans in the essence of needing time to adapt to the darkness. If humans spent extended periods of time in the dark, we would also slowly adjust our eyesight and begin to see things more clearly.
Can turtles see color?
Yes, turtles can certainly see colors. While there is no scientific basis to support turtles having a favorite color, in recent years it has been discovered that unlike humans who can only detect certain colors of red, such as crimson and scarlet, turtles have a rare ability to see many more shades of red. This is due to the presence of a gene called CYP2J19, which is believed to have originated 250 million years ago in an ancient dinosaur-like creature, called an archosaur. Interestingly, this is a common ancestor that turtles share with birds.
Some studies have shown that turtles tend to prefer red, orange, and yellow colors.
Should aquarium lights be on at night?
It is important to understand the amount of light exposure to give your turtle each day. Simply put, this is important for their survival. Similar to humans, turtles depend on day and night to regulate their circadian rhythm, which essentially tells them when it is time to sleep. Additionally, turtles need to bask in some light in order to regulate their metabolism and absorb essential nutrients. Without proper lighting, a turtle can become very distressed, and this can certainly impact their health.
When it comes to when you should give your turtle light, I recommend just following the time of day. Keep the light on during the day time, and turn the light off at night. However, in the summer months it is recommended to regulate light to between 10 and 14 hours per day. This is to ensure they are getting enough light during the shorter daylight hours.
Now that we understand the inner workings and details of a turtle’s eyesight, we can begin to evaluate other questions and scenarios regarding a turtle’s vision.
Can turtles see humans?
Turtles are able to see humans and more so, they are able to make distinctions based upon our physical appearances. Due to the presence of the CYP2J19 gene, we likely appear to them with a red hue, which is vastly different from the way humans see each other. As long as your turtle is in good health, they should have no problem seeing you. You can check out this article to learn about common eye diseases in turtles.
Can turtles see underwater?
Humans have eyes that are anatomically designed to be able to see clearly in air, and this is due to the ability of the eye to refract light. Since we do not spend a lot of time underwater, our eye’s ability to refract light underwater does not exist. This is why our eyesight is mostly blurry when we are underwater.
Since turtles spend a good portion of their life in the water, they have the capability to see well underwater and on land. This is due to the fact that their corneas are flat, but their lenses are spherical. The contrast allows for near-perfect vision underwater. This is an evolutionary adaptation, as they hunt primarily underwater and need to be able to see well to catch their prey. Additionally, because they hunt underwater, they are farsighted which is an additional adaptation that helps them survive.
Hopefully this article has given you a good sense of what and how turtles see. As I previously mentioned, the eyesight of a turtle is quite similar but also different from a human’s eye. As a reminder, it is always recommended to consult your vet if you suspect your turtle has any issue with their eyesight.