A reference to living entities that exist in underground passages or hollows: All troglncoline communities that survive in deep caves depend on replenishment from the outside world, whether through underground streams, or food brought in by other animals.

Many troglocoline species include certain species of fish, crayfish, and flatworms; however, most of them have a ghost-like pallor or unnatural paleness on their outer surfaces and cannot see and some don't even have any eyes.

The troglocoline animals are born, reproduce, and die without ever leaving their caves; unless they are accidentally carried out.