You may find it strange, but there are animals that do not require a sense of sight to survive. Animals without eyes are more common than you might think. In fact, numerous animals manage to survive in the world without eyes. Here’s a list of 11 animals that belong to this group, as well as some information about them!
11 Animals without eyes
1. Mexican Tetra
Scientific Name: Astyanax mexicanus
Mexican Tetras are small, silvery pinkish-white fish that live in freshwater lakes and rivers in the subtropics. They’re found in Mexico, Central and South America, and are most commonly found in freshwater rocky and sandy bottoms. These fish lack eyes because they evolved in caves, and their bodies adapted to their environment.
They can, however, survive in their environment and sense movement through their lateral lines, which are extremely sensitive for these blind species. These fish are usually found in groups and feed on small crustaceans, insects, and annelids.
2. Texas Salamander
Scientific Name: Eurycea rathbuni
The Texas salamander is a one-of-a-kind amphibian found only in the United States. It has no eyes, but it can easily detect vibrations and water pressure.
These creatures have external gills that allow them to breathe and live underwater. They seek small animals by sensing the water pressure around them and moving their heads from side to side until they find their prey, which includes small snails and shrimp.
You can find these fascinating salamanders in San Marcos and Hays county in Texas. They’re found in water-filled caves and are rarely seen above the surface.
3. Sea urchins
Scientific Name: Paracentrotus lividus
Sea urchins, which are related to sea stars and sea cucumbers, are marine animals that live on the ocean floor. These sea creatures have no eyes, but they can see and detect light via photoreceptor cells in their tube feet. Aside from lacking eyes, sea urchins also have no brains or bones.
These blind creatures will eat anything from the ocean floor, including algae, plankton, and mussels. They have five sharp teeth in their mouth that they use to scrape algae off rocks and other surfaces in their environment.
4. Freshwater Hydra
Scientific Name: Hydra vulgaris
The freshwater hydra is a tiny aquatic organism with no eyes that live in freshwater. The hydra lives in lakes, ponds, and streams all over the world. They attach themselves to twigs, rocks, or aquatic vegetation.
This small animal has a very limited diet. Freshwater hydras feed on small creatures that live in their environment, such as mosquito larvae, worms, small crustaceans, fish larvae, and water fleas. Unlike other animals and organisms, these hydras reproduce asexually and form a new hydra by budding.
Since they lack eyes, freshwater hydras use their tentacles to capture prey by waving them in the moving water. The captured prey is paralyzed and killed before being drawn into the hydra’s mouth.
5. Star–Nosed Mole
Scientific Name: Condylura cristata
The star-nosed mole is a small, dark brown mammal that lives in moist areas near water, such as marshes, bogs, fields, and woods. It has does have decorative eyes, which make it nearly blind, but it does have large pink fleshy tentacles shaped like a star on its snout. Their tentacles are extremely sensitive and contain 10,000 nerve endings, allowing them to survive and find food despite their inability to see.
This species can be found in Canada and the eastern United States. They feed on worms, aquatic insects, mollusks, and worms that live under rocks, in dead leaves, or in dirt piles in their habitat areas.
6. Widemouth Blindcat
Scientific Name: Satan eurystomus
The Widemouth blindcat is another eyeless creature found in Texas. It’s a type of catfish found in the freshwaters of Texas’ Edwards Aquifer. Since these fish lack pigmentation in their eyes and skin, they’re mostly white.
These widemouths are also known to be detritivores and carnivores, feeding on both dead matter and a variety of crustaceans found in their environment. Its scientific name is translated as “widemouth prince of darkness” due to the fact that they live in caves and dark environments, and they may be the apex predator in their habitat.
7. Kentucky shrimp
Scientific Name: Palaemonias ganteri
Kentucky shrimp is a small crustacean species native to the United States. They can be found in freshwater lakes and ponds across Kentucky and Alabama.
These shrimps are unusual in that they lack eyes. Their lack of eyes makes them extremely sensitive to their surroundings, which they sense using their antennules.
They’ll eat anything that enters their territory, including dead plants and animals, as well as living plants like algae. Their diet may vary depending on the food available at the time.
Scientific Name: Proteus anguinus
Olms are cave salamanders that live in Croatian and Slovenian subterranean caverns. They have underdeveloped eyes, rendering them completely blind, though they’re still light-sensitive.
Olms consume insects, worms, slugs, and snails as food. When exposed to light, their skin turns pale white or pink and darkens. These animals hunt their prey in a unique way, including hypersensitivity to movement in their surroundings and electro sensitivity.
9. Kauai Cave Wolf Spider
Scientific Name: Adelocosa anops
Kauai cave wolf spiders are only found on the island of Kauai, Hawaii. They live in the Koloa Basin’s caves and lava tubes, where they hunt for insects.
These animals are also the only wolf spider that doesn’t have eyes. This is because these wolf spiders evolved and adapted in their habitat, which is dark environments where eyes aren’t required. They can also detect vibrations and chemical signals from their prey, so they don’t need eyesight to hunt.
10. Red brittle star
Scientific Name: Ophiocoma wendtii
Red brittle star is a type of sea star that lives in the waters from Brazil to Bermuda and can be found at depths of 1-27 meters. The name comes from the fact that their bodies are deep red during the day but turn beige at night. These creatures live on the sea floor, particularly on corals and sea grasses, and feed on small crustaceans and other small creatures such as shrimp and plankton.
These animals have no eyes and rely on their arms to move and sense their surroundings. However, the photoreceptors that cover their bodies enable them to see without eyes, just like sea urchins do.
11. Floppy snake
Scientific Name: Atretochoana eiselti
Floppy snakes, also known as penis snakes, are a species distinguished by their unusual appearance. These animals, however, aren’t snakes, but serpentine amphibians, which are amphibians that resemble snakes.
They can be found in Brazil, especially near the mouths of the Amazon and Madeira rivers. These amphibians have no eyes and live in the water, eating small fish, worms, and other aquatic animals. Floppy snakes can grow to be 30 inches long and live for 5-10 years.