Do Sharks Close Their Eyes?

Sharks are interesting animals that have many myths and misunderstandings associated with them. People often wonder if sharks can close their eyes. Yes, sharks can close their eyes, but it is not simple.

Can Sharks Close Their Eyes? The Role of the Nictitating Membrane

Sharks do not have eyelids like humans. Instead, they have a see-through cover called a nictitating membrane that guards and shields their eyes. This membrane can move across the eye to protect it from harm when the shark is hunting or defending itself.

However, the nictitating membrane does not shut the eye entirely, like human eyelids do. Sharks have excellent eyesight, which they use to move around in the ocean and hunt for prey. If they closed their eyes completely, they would not see properly, so they have adapted to use the nictitating membrane.

Why Sharks Need the Nictitating Membrane and Cornea for Protection

Sharks have another way to protect their eyes. They have a clear layer of tissue called the cornea, which acts as a shield against things that could damage their eyes, such as debris. This is especially important for sharks that swim close to the ocean floor, where there are rocks and other dangerous objects that could harm their eyes.

So, even though sharks don’t have typical eyelids, they have a system that keeps their eyes safe from harm. The nictitating membrane and cornea work together to ensure that sharks can see well and avoid danger in the ocean.

Not All Sharks Have the Same Type of Nictitating Membrane

It’s worth noting that not all sharks have the same kind of nictitating membrane. Some sharks have more see-through membranes, while others have less. The type of membrane depends on the shark’s diet, habitat, and other factors.


In conclusion, sharks can close their eyes, but not like humans. The nictitating membrane and cornea work together to keep sharks’ eyes safe and clear while they swim in the ocean. These adaptations are some of the unique features that make sharks such amazing creatures.