Hydras are the relatives of jellyfish with tentacles. You must have studied how hydras move using their tentacles. They use their tentacles to sting and hunt other smaller invertebrates in an aquatic environment. They do not have eyes but have the capability of responding to light.
Researchers said on Thursday that the red brittle star, called Ophiocoma wendtii, is only the second creature known to be able to see without having eyes - known as extraocular vision - joining a single species of sea urchin.
Springtails. What is this? Springtails are so-called because they move around by leaping, which they can do using some kind of spring on their body. These eyeless, wingless insects are ancient and primitive, so they have been around for a long time.
Interestingly enough, in our versatile animal kingdom, there are multiple animals that are born blind. One of them is the eyeless shrimp, which only has light perception. Another one is the star-nosed mole, the fastest-eating mammal in the world, who uses touch as their main sensory organ.
Blind mole rats appear eyeless and earless, as the functioning remnants of these structures are covered by fur and are therefore not visible. The tiny eyes are hidden beneath the skin, and the external ears are reduced to slight folds.
You know how we (humans) have eyeballs? Well, owls don't. They have eye tubes or cylinders, rod-shaped eyes that do not move in their sockets as eyeballs do. Instead, owls have to move their bodies or heads in order to look around.
Snakes have cones and rods in their eyes that enable them to see in two-dimensional color: blue and green. How well a snake can see depends on what species it is, where it lives in its natural habitat, and if it is on alert. For example, snakes that hunt during the day—like false water cobras—have great eyesight.
There is an urban legend claiming snakes are blind, but it is a myth. While blind snakes exist (the Indotyphlops braminus, whose common name is, appropriately, blind snake), most of them aren't blind and can see things with their eyes.
Several ant species, such as army ants, spend the majority of their life underground and are completely blind. Ants with smaller eyes have a smaller visual field, while species with compound eyes, especially larger ones, have an expanded and better vision.
Bats have small eyes with very sensitive vision, which helps them see in conditions we might consider pitch black. They don't have the sharp and colorful vision humans have, but they don't need that. Think of bat vision as similar to a dark-adapted Mr.
A giant squid captures its prey by using its two long feeding tentacles to grab an unsuspecting victim and bring it toward its arms. Then the squid chomps down on its prey with its strong beak. Since squid live in the dark deep ocean, they have no eyes at all.
Each cockroach has eyes, a mouth, salivary glands, antennae, brain, heart, colon, reproductive system, mid-guts, legs, esophagus, gastric caecea, fat bodies and malpighian tubules. Cockroach eyes contain more than a thousand lenses, allowing them to see multiple things at once.
The visual system of an ant is comprised of a pair of compound eyes and a set of simple eyes called ocelli.
Snails, jellyfish slugs, and worms are some examples of animals that do not produce sound to communicate.
Butterflies have two eyes just like we do. But butterfly eyes are called compound eyes because they have many, many lenses. That means butterflies can see many different things in many directions all at the same time.
Snails have an eye at the top of each taller stalk, allowing them to see any obstacles or predators nearby. Whilst we humans have to turn our heads in order to look around us, land snails can actually turn their stalks without moving their bodies, providing them with a great field of vision.
Ants do not breathe like we do. They take in oxygen through tiny holes all over the body called spiracles. They emit carbon dioxide through these same holes. The heart is a long tube that pumps colorless blood from the head throughout the body and then back up to the head again.
Ants have two stomachs
One stomach is for holding food sources for their own intake, while the second stomach is to hold food sources to be shared with others. The process is referred to as trophallaxis and permits a colony to work efficiently.
Animals, including ants, have specialized sensory neurons that detect and alert them to harmful stimuli, such as temperature, pressure, or chemical changes. These pain-sensing neurons are called nociceptors.
Sharks are not blind, and their vision is far better than we can imagine. While sharks have trouble distinguishing colors, their vision is still good enough to accomplish death-defying feats when hunting their prey.
With the exception of a few species that have adapted to daytime hunting, most snakes do not see well. Generally they can see shapes but not details. This poor eyesight probably owes to their evolutionary history as burrowers, living in the dark where eyes weren't much use.
Snakes have infamously poor eyesight, which is why they resort to sticking out their tongues all the time to get a sense of their surroundings.
Starfish have eyes
Whilst their eyes may not be able to see in fine detail like our eyes can, they are able to detect different shades of light allowing them to navigate their surroundings - allowing them to hunt for food and hide from predators.
Snakes have a small notch in their lips that they can stick their tongues through so they don't need to open their mouths to smell.
Lizards' eyes can see colors that we can't, and they can focus on objects up close and far away with ease. They even have a “third eye,” usually located atop the head, which helps to sense changes in light and darkness and regulate hormone production.