All cave animals and organisms fit into one of three categories of cave life. Placement in these categories depends on how much time the organism actually spends in the cave.
We call the first type trogloxenes. You can look at the word origin to figure out what kind of creatures fall into this category. Troglos is the Greek word for cave, and xenos is the Greek word for guest. So, you can think of trogloxenes as cave visitors. They come and go at will, but use the cave for specific parts of their life cycles -- hibernation, nesting or giving birth. A trogloxene will never spend a complete life cycle in a cave. The most familiar trogloxenes are bats, bears, skunks and raccoons. Even moths are trogloxenes. Trogloxenes have no special adaptations to the cave environment.
Next, we have troglophiles. From the Greek -- troglos for cave, and phileo for love. Love? Well, troglophiles are animals that can survive outside the cave, but may prefer to live inside it. They leave the cave only in search of food. Some examples of troglophiles include beetles, worms, frogs, salamanders, crickets and even some crustaceans like crayfish. A troglophile can live its entire life either inside or outside of the cave.
The creepiest -- and most fascinating -- types of cave life are the troglobites. Again -- troglos for cave and this time bios for life. Troglobites spend their entire life cycle within a cave. They're found only in caves and wouldn't be able to survive outside a cave. The troglobites are the animals that have adapted to cave life. They have poorly developed or absent eyes, little pigmentation and metabolisms that allow them to go a long time without food. They also have longer legs and antennae, allowing them to move and locate food more efficiently in the dark. Troglobites include cave fish, cave crayfish and shrimp, millipedes, as well as some salamanders and insects.
Keep reading to learn about the different habitats within a cave and how each area plays host to various animals.