The Movile cave was discovered in Romania in 1986. However, it has been in existence for over 5.5 million years. The cave is 12,000 square meters and the temperature inside is 25 degrees celsius. The cave only contains half of the amount of oxygen then normal.
Animals moved into the cave because of the winter. Some were searching for a new place to live. They have identified 48 different species. Of the 48 different species there are 33 that have not been seen anywhere else in the world.
Shortly after moving into the cave. Limestone cast made of clay,silt, and sand dropped and completely sealed the cave. With no light they were unable to see.
They found ways to survive the cold, polluted air, and limited food. The food came from frothy foam sitting on top of the water from 25,000 year old spongy sandstones.
Overtime they started changing. They started growing very-long antennas to help them feel around in the darkness. Some were born without eyes and with lost pigment in their skin. However, some were still eaten by predators.
After its discovery it still remains a mystery on how these animals survive. Researchers are only able to explore the cave for 5-6 hours before their kidneys pack-in. Due to the caves atmosphere it will be many years before they are able to fully explore the cave.