BBC Earth: Movile Cave has been cut off for millions of years. Its air is thick with harmful gases, yet it is home to an array of strange animals
A cave woodlouse
An unidentified leech from Movile Cave
Despite a complete absence of light and a poisonous atmosphere, the cave is crawling with life. There are unique spiders, scorpions, woodlice and centipedes, many never before seen by humans, and all of them owe their lives to a strange floating mat of bacteria.
Strangely, the worse the air gets the more animals there are. It’s not at all obvious why that should be, or how the animals survive at all.
A waterscorpion attacks its crustacean prey
An unidentified pseudoscorpion
Two woodlice which lack skin pigment
Without any signs of water reaching the deep cave from the surface, it is unclear how the animals in the cave survives. Tests have shown that the water flowing in does not contain any food particles. Instead, the food comes from the strange frothy foam sitting on top of the water. This floating film, which looks like wet tissue paper and can even be torn like paper, contains millions upon millions of bacteria known as “autotrophs”.
A centipede with extra-long antennae
In 1996, researchers categorised the animals in the cave. They included 3 species of spider, a centipede, 4 species of isopod (the group that includes woodlice), a leech never seen anywhere else in the world, and an unusual-looking insect called a waterscorpion.
“Almost 30 years after its discovery, Movile Cave remains perhaps the most isolated ecosystem on the planet. It surely has many more secrets to give up. There are plenty more organisms buried in the cave’s sediments, waiting to be identified, and they could help us understand some of our deepest questions about the nature of life.” — BBC Earth