--- title: Caves: bat clouds, blind fish, the olm, glowworms and a sealed cave — a lesson of Mova's school · trees and pragmatics description: «Caves: bat clouds, blind fish, the olm, glowworms and a sealed cave», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Walk a little way into a cave and the daylight disappears; deeper in, it is pitch black all day and al --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Caves: bat clouds, blind fish, the olm… # Caves: bat clouds, blind fish, the olm, glowworms and a sealed cave Lesson 179 of the biology course of Mova's primary school: 15 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/0/) — Walk a little way into a cave and the daylight disappears; deeper in, it is pitch black all day and all year, so eyes stop being useful. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/1/) — Cave animals find their way in other ways: bats and swiftlets click and listen to the echoes, cave crickets feel the way with very long feelers, and some fish and the pale olm have lost their eyes altogether. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/2/) — Food is scarce in the dark, so a lot of it comes from outside: bats fly out at sunset to eat insects and come back to drop their droppings, which feed beetles and worms on the cave floor. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/3/) — In Romania there is even a cave sealed off for millions of years where the air smells of rotten eggs, and the whole food chain starts with bacteria eating chemicals instead of sunlight. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/4/) — Bracken Cave in Texas has millions of bats that fly out at dusk to eat insects, a cloud so big it shows on weather radar, and they eat tons of insects every night. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/5/) — Bats find their way by echolocation, making clicks and listening to the echoes, but bats are not blind: many see well, and fruit bats use eyes and noses more than echoes. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/6/) — Blind cave fish have lost their eyes because in total darkness eyes are useless and making them costs energy; Mexican cave fish have river relatives with eyes. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/7/) — The olm is a blind, pink cave salamander from Slovenia and Croatia that lives in water, can go years without food and may live about a hundred years. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/8/) — In Waitomo Caves in New Zealand, glowworms, which are fly larvae (young flies, like maggots), glow to lure insects into sticky threads and make the ceiling look like a starry sky. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/9/) — Cave swiftlets are among the very few birds that echolocate, and some swiftlets build nests from their own saliva. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/10/) — Cave crickets have very long legs and feelers because in the dark touch is more useful than sight. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/11/) — Bat droppings, called guano, pile into huge heaps that feed cave beetles and worms, and guano was once mined as valuable fertilizer. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/12/) — Cave animals are cut off from each other, so many caves have kinds found nowhere else, and tiny animals live two kilometres down in Krubera Cave in Georgia. - [13](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/13/) — Stalactites grow from dripping water that leaves behind a tiny bit of chalky mineral, over thousands of years, and touching them can stop them growing, because oil from skin stops the mineral sticking. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/179-caves-bat-clouds-blind-fish-the-olm-glowworms-and-a-sealed-cave/14/) — Movile Cave in Romania was sealed off for millions of years until 1986; bacteria make food from chemicals, and dozens of kinds of animals live there, most of them nowhere else. - ← previous: [Mangroves: trees in salt water, mudskippers, archerfish and swimming tigers](https://md.mova.elamur.ai/free/en/corpora/school/biology/178-mangroves-trees-in-salt-water-mudskippers-archerfish-and-swimming-tigers/) - next →: [The Galápagos: giant tortoises, sea iguanas, Darwin's finches and tame sea lions](https://md.mova.elamur.ai/free/en/corpora/school/biology/180-the-galapagos-giant-tortoises-sea-iguanas-darwins-finches-and-tame-sea-lions/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)