Animals with No Eyes: Cave Adaptation

In caves, food is scarce and predators are everywhere. The creatures in caves have their own special adaptations that allow them to survive deep under the surface of the earth.

Troglobites

The deepest part of the cave is called the dark zone. Some amazing animals managed to survive in this dark zone. Such animals are called troglobites or ‘cave-dwellers’. Troglobites live in a world where eyes are useless and color does not matter. To survive, troglobites have adapted themselves to the dark. In fact, they are so adapted to their cave environment that they will not be able to survive anywhere else.

Cave Adaptation

In a world of black, eyes are useless. Troglobites have adapted to living without seeing. Most troglobites are blind. In fact, some cave creatures are born without any eyes at all. Another adaptation has to do with color – or the lack of it. Unlike animals above ground, troglobites do not need to camouflage. Their predators probably do not have to see them anyway. Many cave animals have lost their markings and their bodies have turned a ghostly white.

Some troglobites have developed another way to know what is going on around them. These animals have a sense organ on their bodies that picks up vibrations or changes in pressure. It allows animals to know where rocks or bumps are or where other creatures are moving.

Examples of Troglobites (Cave-dwellers)

The Blind Cave Tetra could not live anywhere other than its home in the total darkness of the cave.

The Belize Land Crab has turned a ghostly white after adapting itself to the environment of the cave.

Grotto Salamanders or ‘Ghost Lizards’ are white or pale pink with light orange stripes on their tails and feet. These creatures are born with both gills and eyes. But as they become adults, three things happen. First, they grow smaller, not bigger. Second, their eyes stop working and are slowly sucked back into their bodies. Third, their gills close up and they begin to breathe through their skin.

The Olm Salamander lives under water in some caves. It has no eyes or color. But it can live to be 100 years old.

Many cave millipedes eat rotting animals or plant pieces.

No eyes, no color. That’s the life for this cave crayfish.

Being an endangered species, the translucent cave shrimp has no eyes. 

The No-eyed Big-eyed Spider lives only in the warm, humid caves in Kauai, one of the Hawaiian islands. They changed overtime. Their eyes got smaller until they finally disappeared. They used sensors in their legs to find food. The darkness became a tool for hunting and for hiding.