Researchers looking for cave-dwelling animals near the Black Sea discovered what may be the world's deepest land animal. The eyeless and wingless insect, part of the springtail family, was found over a mile below the surface (6,500 feet or 1,980 meters), researchers reported.

The springtails live in complete darkness and feed on fungi and decomposing matter. Researchers said they were surprised to find this kind of life in such a cold, dark place. Temperatures in the cave hovered around the freezing mark.

Until now, the deepest known land animals were an insect known as a silverfish and a scorpion, both found at less than half of the depth of the springtail - only 3,000 feet.

The Krubera-Voronja cave, where explorers found the springtails, is the deepest known cave on Earth. Researchers have been exploring the cave for 10 years in treacherous conditions.

There are no machines, only human work, Sofia Reboleira, study co-author and cave biologist from the University of Aveiro in Portugal told LiveScience. At the base camp we have no freshwater, only melted snow, and the food has to be rationed to feed almost 30 persons during 30 days.

Searching for cave-dwelling animals is a task that requires several hours of active search - extremely difficult in the cold conditions of the cave, because of the risk of hypothermia, Reboleira said.

The insect, named Plutomurus ortobalaganensis, was one of four new species of springtail found in the cave and was found deeper than any of other species.

The lack of eyes and wings is common for troglobionts, or cave dwellers, Enrique Baquero, study co-author and taxonomist at the University of Navarre in Spain told The Epoch Times. Nevertheless, it has pigment, usually absent in animals that are strict troglobionts.

The insect most likely moved underground recently where pigment becomes useless in the dark, the authors concluded.

The study was published in the journal Terrestrial Arthropod Reviews on Wednesday.