There are animals that can do without their sight, mainly because there is not much light in their environment. This is the case of animals in the deep sea, underground terrestrial animals or those who live in caves. But this does not mean that they are completely isolated and without receiving stimuli from their environment. On the contrary, they have developed various adaptations, such as a highly developed sense of smell or hearing. Eye atrophy is a great strategy to reduce energy expenditure, because by not using them and disappearing they can invest their energy in improving other organs to know their environment.
Star-nosed mole (Condylura cristata)
These subterranean moles do not need to see because they have a very advanced nose , full of tentacles with which they can mentally reconstruct their surroundings with the information it provides. It can not only pick up odours, but also vibrations from its surroundings and the electrical fields of other animals. His eyes are greatly reduced. This also works to protect you from dust that is underground.
Dumbo octopus (Grimpoteuthis spp.)
Although they have large and disproportionate eyes , they are not functional . They cannot clearly distinguish what is happening in their environment. They only serve to detect movements and lights. They really don’t miss much by not having eyes, because they live in the deep sea where life is scarce. To help detect its surroundings, it has suction cups with filaments on its tentacles.
Like Dumbo the octopus, discover other Animals of the deep sea , here.
Axolotl (Ambystoma mexicanum)
Axolotls have very small eyes, without eyelids and their vision is limited, they can only see shadows . But they make up for it with a very keen sense of smell that they use to detect their prey. Being aquatic organisms, they can perceive the vibrations that other organisms generate in their environment.
Blind snake (Blanus cinereus)
This worm-like snake has a plate over its eyes, as it is subterranean in habit and does not need vision. It can also be found under stones or leaf litter. Their sense of smell and hearing are highly developed for capturing prey such as insects .
Golden or chrysochlorid moles (family Chrysochloridae)
They are mole-like mammals, but despite their name, they are not. They grow completely without eyes . Even this area is covered by hair. Having burrowing habits, they have developed strategies to be more efficient.
His metabolic rate is very low and so is his body temperature. When it is cold they can go into a state of lethargy for up to three days in which they reduce their physiological functions. Not having eyes does not make them defenseless. They can hunt a wide variety of African insects.
Mexican tetra (Astyanax mexicanus)
They are fish that live in caves . Some populations are deeper into the caves and others are closer to the coast. The former have completely reduced eyes, larger teeth, reduced pigmentation, and increased development of taste buds to compensate for impaired vision due to lack of light.
Proteus (Proteus anguinus)
They are amphibians that live in caves, similar to snakes but with small legs. They are born with normal eyes, but as they grow they atrophy due to lack of light and develop a layer of skin over them . Its head is very large and flattened to accommodate as much sensory information as possible. They can detect by smell what organism they have nearby and can feed on it. By taste they can know the composition of the water and the ear can detect movement in water and on land.
Texas blind salamander (Eurycea rathbuni)
It is very similar to axolotls, but it is actually a salamander. Their eyes are not functional , they are covered by skin and cannot be distinguished. It lives in caves and has external gills to capture oxygen. Your skin has evolved to detect minute changes in your environment. His head is also very large and flattened to enhance his sensory organs. You can go a long time without eating .
Clams (class Bivalvia)
These bivalves lack a cephalization and, therefore, eyes. They do have sensory organs arranged in the mantle, that is, the fleshy part inside their shells. It has chemoreceptors and some species can detect light using ocelli, which are very rudimentary eyes.
Hamster (family Cricetinae)
Hamsters have very poor daytime vision , as they are animals that come out at night. At night his vision improves a little, being able to distinguish a little better. However, his vision cannot go very far and is very blurry.
This is useful to know if you are going to have it as a pet. It is better not to place it at great heights since they can hurt themselves when dropped, due to not knowing how to calculate heights. They use their excellent sense of smell and hearing to know what is going on in their environment, as well as their whiskers to calculate spaces more effectively.