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There are more than 500 shark species in today’s world and they come in all different shapes and sizes. They are among the most capable predators in the world and are highly adapted to the areas they live in. sharks have some of the most advanced senses of any animal and are known for their ability to smell blood, but what about sight? One of the most fascinating things is the deep, unfathomable depths of a shark’s eye. Join us as we discover how shark eyes work and find out everything you need to know about them.
How do Sharks Eyes work?
Shark eyes are often considered one of the most complex and least understood aspects of sharks. Therefore, it probably comes as a surprise that their eyes are actually quite similar to ours. Like us, they have a lens, cornea, pupil, retina, and iris, and these parts all work much the same as ours.
However, sharks have duplex retinas that contain both rods and cones. Rods and cones are the photoreceptor cells that determine light and dark (rods) and color (cones). For a long time it was thought that sharks lacked the necessary cells to see color. However, recent studies have shown that they can actually see in color, but it is not known to what extent. Incredibly, the number of rods and cones varies by species, so some sharks can see better than others.
Sharks also have a unique ability to see well in dark or murky waters. Tapetum lucidum is a layer of mirrored crystals located just behind the retina. Light passes through the retina, hits the crystals, and is then reflected back onto the retina. This means that the light is available to the retina twice and increases visibility in low-light areas. In fact, they can see about ten times better than we can in cloudy, dark, and clear water. This is a big advantage for sharks because there is very little light in the ocean as the ocean gets deeper. incredible, cats also have this tapetum lucidum. This is why both cats and sharks eyes seem to glow in the dark.
Do sharks have good eyesight?
While sharks were thought not to have the best eyesight (especially considering that they sometimes confuse us with seals), they even have fairly good eyesight in certain circumstances. We’ve already found that their low-light vision is much better than ours, but they can even change their field of view whenever they want.
Sharks can see both stereoscopically and monocularly. Stereoscopic is three-dimensional vision and that’s how we see. Images from both eyes are combined, giving our vision shape, depth and distance. Monocular vision uses the image of only one eye. Although monocular vision gives poor depth perception, it increases the quality of vision.
However, despite being able to see in good quality, sharks can only see up to a distance of about 50 feet. They also have a few blind spots. Sharks’ eyes are located on either side of their heads, allowing them to see nearly 360 degrees. Despite this, they have a blind spot in front of their muzzles and behind the top of their heads. So because they can’t see that far, they need to be fairly close to their prey before attacking, but they can’t really see anything in front of them at all!
How do sharks protect their eyes?
Since sharks are some of the most capable and active predators in the sea, their eyes are clearly at high risk of injury when they attack their prey. Animals such as seals or even other sharks can easily cause serious damage as they scurry around or bite. So how do they manage to protect their eyes?
Sharks are often confused with the fact that they have no eyelids because they don’t blink. They do have eyelids, they just don’t have to blink because the water is constantly cleaning their eyes for them. Although sharks have eyelids, they do not close completely. Therefore, sharks use one of two methods to protect their eyes and which method they use generally depends on the species. One method is to use a nictitating membrane. This membrane is transparent and slides down from under their eyelid to cover their eyeball, creating a protective layer. This membrane can be used when fighting with other sharks and while hunting.
The second method is used by sharks that do not have nictitating membranes and is the method used by great white sharks. There are often stories of how you can see the whites of their eyes when they attack. Contrary to the belief that it’s just something they do during a frenzied attack when fueled by the smell of blood, they’re really just protecting their eyes. Because they have no nictitating membrane, great whites roll their eyes back into their heads to protect their eyes. This is called ocular rotation and means that in the last moments before they attack, they are essentially blind. Therefore, the sharks must rely on their other senses — such as electroreception — to locate and attack their prey.
Is eyesight essential for sharks?
How essential vision is for sharks depends largely on the species and their habitat. Deep-sea sharks that live in the darkest parts of the ocean where there is very little light rely more on their other senses, such as their lateral lines and ampullae of Lorenzi (electroreceptors). However, sharks that live closer to the surface are quite dependent on their eyesight. Some species – such as the Ganges river shark – swim along the bottom of the river while scanning the water above for prey. This means that they actively use their eyesight for hunting.
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