7 creatures that can sleep with their eyes open

Most animals close their eyes when they sleep. But did you know some amazing creatures can actually sleep with their eyes open?  It might seem strange, but these animals have developed abilities to rest while staying alert to their surroundings. Some do it for survival, while others have evolved this ability for totally different reasons.  Here are seven amazing creatures that can sleep with their eyes open and how they do it: 1. Dolphins Dolphins are known for their intelligence, but did you know they can sleep with one eye open? Dolphins are unique because they sleep with one hemisphere of their brain at a time. This means while one half of their brain is at rest, the other half stays awake and alert, allowing them to keep an eye on their surroundings and breathe at the surface.  2. Seals Seals are another marine animal that sleeps with their eyes open. Like dolphins, they have a special way of sleeping. Seals often sleep while floating in the water, and they can keep one eye open to watch for any dangers nearby.  3. Bullfrogs Bullfrogs are known for their unique sleeping habits too. These amphibians can sleep with their eyes open and even appear to be awake while resting. Unlike other animals, bullfrogs don’t have eyelids, which makes it easier for them to sleep without fully closing their eyes. They can also remain still for long periods, helping them avoid predators while they take a break. 4. Birds Many birds have the ability to sleep with their eyes open, particularly when they need to stay alert in their environment. Birds have a special muscle that allows them to lock their toes onto branches or surfaces, keeping them secure while they sleep. Some species, like the great horned owl, can sleep while keeping their eyes partially open. This allows them to spot any potential threats or changes in their surroundings while they rest. 5. Horses Horses are known for their ability to sleep standing up, but they can also sleep with their eyes open. Horses have a unique system of locking their legs to keep themselves standing without using much energy. When they doze, their eyes may stay open, allowing them to remain aware of their surroundings, especially in the wild when they need to be alert for predators. ALSO READ: These animals can survive without food for months 6. Sharks Sharks are perhaps one of the most fascinating creatures that can sleep with their eyes open. Unlike most animals, sharks don’t have eyelids, so their eyes stay open even when they rest. Some species of sharks, like the nurse shark, also need to keep swimming to breathe, so their brain stays partially active while they sleep. This allows them to continue moving and avoid danger while still getting some rest. 7. Crocodiles Crocodiles are known for their tough exterior, but they also have an interesting way of resting. Crocs can sleep with their eyes open, making it easier for them to spot any potential threats in their environment. They also have a special mechanism that helps them control their sleep, allowing them to stay alert to movement in the water or on land. RELATED: 5 animals that never sleep and why