Which animal has the largest eyes in the world? Do dragonflies see in slow motion? Are big cats colorblind? AnimalSake answers all these questions, and describes the animals with the keenest eyes in the world.
An Honorable Mention
The largest eyes in the world belong to the colossal squid, the largest invertebrate in the world. Fully-grown squids, in the wild, have eyes that are more than 30 cm―one foot―in diameter! The large eyes are necessary to survive in the squid’s deep, dark habitat.
The human eye is said to have a resolution of 576 megapixels, which is stronger than most animals. But many animals put us humans to shame when it comes to the best eyesight in the world.
Vision is probably, the most important tool in the wild. Predators have perfected accurate, powerful vision to spot a single target, while prey animals have developed vision highly sensitive to movement, alerting them of the imminent danger. Birds, and birds of prey in particular, rely on vision to a great degree. Generally, birds have a weak sense of smell and hearing (though there are exceptions to both), and largely depend on vision to kill and survive.
The sense of vision has developed in countless different ways. It is virtually impossible to list animals according to their sense of vision, since all of them have different types of vision. It would be unfair to rank the chameleon’s weird and wacky eyes above a cat’s eyes, because the two serve different purposes, and have evolved into completely different designs.
Here is a list of the animals with the best and most finely tuned eyesight.
Animals with Incredible Eyesight
Birds of prey, such as eagles and falcons, have some of the best eyes in the animal kingdom. These majestic birds are designed to spot a prey from high above, and then swoop down fast to catch it, before it realizes what has happened. Their eyesight is one of the sharpest among all animals, and some species can spot something as small as a rabbit, from more than a mile away!
Like most predators, their eyes are forward-facing, which gives them excellent binocular vision, while compromising the unnecessary enhancement of the field of view. Not all birds of prey employ the ‘soar high, swoop low’ technique, but all of them rely extensively on their excellent vision to hunt.
Though technically a ‘bird of prey’, owls deserve a special mention. In the animal kingdom, owls have one of the largest eyes relative to total body size, and are among the very few nocturnal animals who do not use echolocation or reflecting membranes behind their eyes, known as the tapetum lucidum. They rely on their large eyes, which are actually larger than their brains, to let in as much light as possible. The eyes are not that powerful though, and the excellent visual navigation is actually done thanks to a section in their brains that can identify the tiniest detail in a relatively blurry, but bright picture. In spite of this, owls don’t rely extensively on their sight but their sense of hearing, for hunting.
Here, owls have been considered as a single class, since the difference in eyesight between species, if at all, might be negligible, and may have been due to adaptation and evolution.
Cats have excellent night vision, and big cats―tigers, lions, jaguars, and leopards―have extremely effective night vision, which allows them to hunt under the cover of darkness. Cats have a reflective layer behind their eyes known as the tapetum lucidum. This layer increases the amount of light entering the eye, and enhances vision in low light conditions.
Cats are much more sensitive to light than humans, since they have more rod cells in their eyes. But their eyes contain nowhere as much cone cells―the cells that determine the ability to distinguish colors―as humans, and are thus, nearly colorblind. They can distinguish between a very limited range of colors.
Like owls, big cats too have been considered as a single class, since the difference in eyesight between species, if at all, might be negligible, and may have been due to adaptation and evolution.
Prosimians, which includes lemurs, tarsiers, bushbabies, and lorises, are distant relatives of apes and humans. They have some of the largest eyes relative to body size, which are needed for their nocturnal behavior. All prosimians, except tarsiers, are also aided by the tapetum lucidum.
Dragonflies are expert insect predators, and are among the fastest insects in the world. Their eyes are, quite possibly, the most amazing ones found on insects. Dragonflies have compound eyes, aided by three separate eyes known as ocelli. While the compound eyes are pretty effective on their own, the ocelli help dragonflies to detect and react to motion much, much faster than humans. This has led to the belief that flies see in slow motion, which can be said is true, though not entirely accurate.
Goats have some of the weirdest eyes among mammals, but they serve an essential purpose very effectively. Goats are prime targets for many predators, particularly big cats. Their horizontal and almost perfectly rectangular pupils give goats a field of vision of 330°. This means that they can see virtually all but their own backs without turning their head! This gives them a much better chance of noticing a predator before it gets too late.
Chameleons have probably the most famous eyesight in the animal kingdom. They can swivel their eyes independent of each other, and can process completely different images at the same time. This phenomenon has been widely documented, but its neural connection is still not properly understood.
These little weirdos, who are neither aquatic mantises nor shrimp, have possibly the most complex and undecipherable eyesight in the world. Mantis shrimp have compound eyes (like the dragonfly) mounted on stalks, which can move independently. Their eyes are divided into three segments, so that it has a ‘trinocular’ vision with each of its eyes. Humans, on the other hand, only have binocular vision, thanks to our two precious eyes. Mantis shrimp see the world in 12 color bands, as opposed to a paltry 3 in humans. They can also see circular polarized light, which is the equivalent of putting on 3D glasses all the time. Why these crustaceans have these abilities, and how exactly are they employed, is still a matter of mystery and conjecture.
While humans take the cake in various ways among the animal kingdom, we are certainly beaten comprehensively by animals when it comes to the most important sense of all―vision.