Predators need early detection of their prey, and for others, it is a defense mechanism to spot attackers and know when to flee for survival. Animals have evolved their eyesight to suit their environment. For example, the meerkat has grown dark fur around their eyes like a pair of natural sunglasses to block the sun’s glare.
So, which animals have the best eyesight?
Best Night Vision - Owls
The winner of this category is the owl, whose enormous eyes allow in plenty of light. Owls fly slowly and silently, catching their prey unaware. They hunt at night when there is less competition. Their eyes have large pupils. Bigger pupils mean more light passes through to the lens and reaches the retina.
Owls have a high density of light-sensitive rod cells within the retina, which are exceptionally sensitive to light. Humans have roughly 200,000 rods per square millimeter, whereas an owl’s eye has about one million rods per square millimeter. Some owls can see an incredible 100 times better than a human in dim light.
An owl has a 110° field of vision, with only 70° binocular vision, compared to a human’s 180° field of vision and 140°binocular vision. However, the owl has 14 vertebrae in its neck, allowing it to swivel its head 270°.
The night predator is far-sighted and unable to see things close up, but they can spot their prey up to a mile away in dim light.
Best Underwater Vision - Sharks
Like owls, sharks have abundant rod cells, allowing light in through dark, murky waters. They have a biological reflector system known as tapetum lucidum. It is a layer of tissue behind the retina, and its purpose is to reflect visible light to the retina, increasing visibility in dark and cloudy water.
Sharks have ten times better vision than humans and can detect movement up to 85 feet (25 meters) in relatively clear water. They do not have to blink, and their eyelids only partially close. To protect their eyes, sharks have a clear protective membrane that covers their eye when attacking prey. In the case of the Great White shark, without the protective membrane, they roll their eyes towards the back of their head.
Although sharks have excellent underwater vision, they have two blind spots, one in front of their snout and the second behind their head. They overcome this weakness by moving their heads from side to side and circling their prey.
The Hammerhead shark has the best eyesight of all sharks. With its odd-shaped head, its field of vision overlaps behind them, enabling them to see 360°.
Broadest Vision - Chameleon
Chameleons lie in wait, motionless for an unsuspecting grasshopper or locust. Their excellent broad eyesight does not miss much. Their domed eyes have a range of about 180° horizontally and 90° vertically, compared to humans, who have a focal range of approximately 80° across and 70° vertically.
Like most lizards, a chameleon’s eyes are mounted on small turrets, allowing the reptile to move its eyes independently. It means they can see in monocular or binocular vision and simultaneously watch two objects without moving their heads. Chameleons have an eyelid permanently fused to the eye leaving only the pupil clear, which protects their protruding eyes.
Using their efficient broad vision assists the chameleon in hunting its prey and escaping predators, such as snakes, birds, and the occasional monkey.
Most Sophisticated Eyesight - Mantis Shrimp
Contrary to what their name suggests, the Mantis Shrimp is not part of the shrimp family, although it is a crustacean Stomopoda. Over 450 Mantis Shrimp species vary in size from 2 to 12 inches (5 - 30cm). They share their aggressiveness and do not take kindly to intruders entering their territory. They can pack a punch with a speed of 60 mph with their front claws.
The Mantis Shrimp has another remarkable feature, its complex vision. They have at least 12 channels of color, unlike humans, who only have three. They also see UV and polarized light, including circularly polarized. They are the only animal known to see the light move clockwise or anti-clockwise. The human eye cannot see these light aspects with the naked eye.
Their eyes can move independently and are constantly scanning the environment. The Mantis Shrimp has the most unique eyesight system in the animal kingdom.
Best of the Animal Kingdom - The Eagle
You may have heard the saying ‘eagle eye.’ Well, it might be no surprise that eagles have incredibly sharp vision, the best in the animal kingdom. An eagle can spot a rabbit almost two miles away.
A human has average eyesight if they have 20/20 vision. An eagle can have up to 20/4 or 20/5 vision. It means they have the ability to spot their prey four or five times farther than a human. Eagles also have a greater capacity to see colors. Due to the angle and size of an eagle’s eye, they have a 340° field of vision, in contrast to a human’s 180°.
If a human were to swap their eyes for an eagle, they would be able to see the equivalent of an ant from the top of a 10-story building. They would see the view magnified and vividly colored and experience a broader field of view.
Their eyesight can quickly shift focus and zoom into movement in different directions. Their eyes dilate and constrict to see things up close and at a distance. These specially evolved features enable the eagle to be the King of the skies. Amazingly, the Bald Eagle soars at 10,000 feet (3,048 meters), and as opportunist predators, they can spot a rabbit, rodent, or small bird and eat whatever they can catch.