I’ve never seen a frog blink. So naturally, I wondered whether they even could! After a little research, here is what I found…
So, do frogs blink? Frogs can blink. They generally do so while eating, as frogs use their eyes to push live prey down their throats. Blinking can also help protect the eye from any predator fighting back. Cleaning the surface of the eye – removing debris and keeping the eyes moist when on land are other reasons frogs blink.
In fact, frogs actually blink quite a lot.
I suppose I have not been watching them long enough!
And blinking, as we can see, serves many functions.
It has a range of uses and helps a frog in many ways.
And even more interestingly, frogs have very different eyes to those of us humans.
And it’s all to do with their eyelids!
Let’s find out!
Do Frogs Have Eyelids?
Frogs are known to possess three eyelids – two of which are transparent and sit on the top and bottom of the eye. The third eyelid is semi-transparent and is called the nictitating membrane.
And its that nictitating membrane that is responsible for cleaning.
This is the eyelid that will swipe up any debris from the surface of the eye.
This is also the eyelid that will keep the eye moist – by helping to spread oily secretions.
The other eyelids, on the other hand, will open and close the eyes.
And it is the upper eyelid that is responsible for the blink, as we now know it.
Imagine, therefore, that the nictitating membrane is like a film that is used to protect the eye.
Whether this by keeping water out of their eyes while swimming, or by allowing them to continue observing their environment without losing their focus of sight.
Frogs will blink as and when they need to – this can happen frequently or less frequently depending on the circumstances. For instance, a frog will routinely blink while eating, on the surface of the water, or at any time debris manages to land on the surface of the eye.
Then again, it depends on how you are defining, ‘blink’.
Are you referring to the full closure of the eye – where the upper eyelid fully retracts over?
Or, are you referring to the third semi-transparent nictitating membrane?
Because it makes quite a bit of difference.
The nictitating membrane (or third eyelid) will blink much more frequently than that of the upper eyelid.
Do Frogs Ever Close Their Eyes?
Frogs do close their eyes, but only momentarily while eating and again when they are asleep.
When eating, a frog will close their eyes to support the swallowing of food.
They’ll sink their eyes down into their sockets as a means of pushing live prey down their throat. And the eyes close during this time.
Frogs sometimes close one eye during this process, although it is common to see them close both eyes to get the force they require.
Of course, they’ll also be using other limbs while eating too; front legs, small teeth for gripping, and their long tongues for leverage.
When it comes to sleeping, again their eyes will retract into the sockets.
This time their eyes will bulge down into the mouth, and the third eyelid – the nictitating membrane, will shut over the eye.
So, the other eyelids will remain open.
Instead, the third eyelid is responsible for protecting the eye during rest.
Different species of frogs have different colors of nictitating membrane – some are more clear, others are patterned.
Either way, it is this eyelid that closes and as such, a frog will never completely shut their eyes while they sleep.
Frogs do blink.
In fact, its a pretty important mechanism and one they rely on pretty heavily.
Especially when they eat and particularly when they are submerged in water.
Swallowing, cleaning, protecting; these are all conducted through blinking.
And it’s all possible due to two very different types of eyelids.
The nictitating membrane (third, semi-transparent) is the one to look out for.
As you can now see in action in the video below: