The unusual eyes of animals (II)

Mantis shrimp is considered by many to possess the most unusual eyes in the animal world. Each of their eyes has 12 different light receptors, helping them to recognize colors much better than humans as well as seeing ultraviolet, infrared and polarized light.

>> The most unusual eyes of animals (I)

Stalk fly

This small but strange species is mainly found in tropical forests in Southeast Asia, Africa and a few in Europe and North America. Their names are based on long sections protruding from both sides of the head with eyes and antennae at the end. Male flies often have much longer stalks than female flies and biologists have also determined that females like "guys" with long stalks.

During mating season, males often face face to face and measure the length of their stalks. The child with the "eye" farthest will be recognized as the winner. The male flies also have an extraordinary ability to enlarge their eye stalks by swallowing air through their mouths and blowing it through the tube leading to the ends of the stalks. They mainly do this during mating season.

Spookfish fish

Spookfish is a deep-water fish that has a ghostly appearance and possesses one of the strangest eye structures known to science. Each eye has a bulging part called "excess bag", separated from the main eye by a partition. While the main part of the eye has a lens with functions similar to those of other animals, the "excess bag" contains a curved mirror, a multi-layer complex of guanine crystals. This "mirror" collects light above the naked eye. "Excess bag" reflects light and focuses it on the retina, allowing spookfish to observe both the top and bottom at the same time.

Spookfish fish are the only vertebrates that use the mirror eye structure to look beyond ordinary lenses. These fish are distributed all over the world but we rarely see them because they spend most of their lives at a depth of 1,000-2,000 meters. Spookfish fish eat small crustaceans and plankton. They have an average length of about 18cm.

Spider face demon

Spiders are commonly known as multi-eyed animals (although this varies greatly among spiders, some have 2 or 4 eyes while others have 6 or 8 eyes). The demon-faced spider possesses 6 eyes but looks like only 2 eyes because the middle pair grows bigger than the other 2 pairs. This is an adaptation to nightlife. The demon face spider is endowed with great night vision, not only because of the large eyes but also because of an extremely sensitive cell layer of light covering them. This membrane is so sensitive that in reality it is destroyed at dawn and a new membrane is produced every night. The eyes of demon-faced spiders are considered unusual because they have perfect vision at night despite the lack of tapetum lucidum - a reflective film that helps other spiders (and other predators like cats). visible in low light conditions. Scientists believe that demon-faced spiders are better at observing the night than cats, sharks and owls (animals that have night vision are 100 times better than humans).

Mantis shrimp

Many consider mantis shrimp to be the animals that possess the most bizarre and surprising eyes in the world. Mantis shrimp is not really shrimp, but another type of crustacean belonging to the Stomatopoda set. Known for its aggressiveness and formidable weapons (Mantis shrimp has extremely sharp claws, is powerful and can cut a human finger or even break a glass aquarium with a single attack. ), this creature is voracious predators who live mainly in tropical waters.

Like dragonflies, mantis shrimp eyes are also complex, although there are fewer ommatidia visual units (about 10,000 per eye). However, in mantis shrimp, each ommatidia row has a separate function. For example, some of them are used to detect light, others to identify colors, . Mantis shrimp has a much better ability to recognize colors than humans. Their eyes have 12 types of color receptors, while those in humans are only 3. They also have the ability to see ultraviolet, infrared and polarized light, so they are considered a facility. The most complex sight of all kinds of animals ever known.

The eyes of mantis shrimp are placed at the end of the body and can move independently of each other, rotating to 70 degrees. Another interesting point is that visual information is handled by the eyes of the mantis shrimp, not their brain. Strangely, each of the mantis shrimp's eyes is divided into three parts, allowing this creature to see objects with three different parts of the same eye. This means that, if one eye is lost, the other eye will still be able to assess the depth and distance as well as a human with two eyes.

Three-lobed set

The lobster is one of the most successful animal groups of all time, thriving for nearly 300 million years before dinosaurs appeared on earth. Although some species in this set do not have eyes, most of the rest possess complex eyes similar to insects. The strange thing about the three-lobed eye is that their lenses are made of inorganic calcite crystals, a mineral that is also a major component of limestone and chalk. In its purest form, calcite is quite clear, enough to become a glass material of the eye.

Crystal eyes are unique to the three-lobed set because the complex eyes of modern invertebrates form chitin - an organic substance. Due to the unusual composition, the three-lobed eye is very inflexible and cannot be adjusted to focus. Instead, the lobe treats the focus with an internal eye mechanism, which not only solves any potential problems caused by the mineral lens, but also gives them good vision, possibly Observe objects both near and far at the same time.

In addition, some lobster animals possess real eyes that look very strange. Some have eyes at the end of the long stalks like stalked flies, while others have "eye lids" above the eyes to protect them from bright sunlight. Made from calcite, the eyes of three fossil lobes are easy, and so we can know more about their eye structure and vision than any other prehistoric creature.

Goat

We often imagine that the pupils in the eyes are round. However, the eyes of goats and most other ungulates contain horizontal slots, almost turning into rectangles when expanding. This feature gives the goat a wide-ranging vision of 320 - 340 degrees, meaning that they can see almost all of them around without moving (people have a wide view of 160-210 degrees. ). Therefore, animals that possessed rectangular eyeballs may look better at night due to larger pupils, which can be more tightly closed during the day to limit light. Interestingly, octopus also has rectangular pupils.