How do caves form?
Caves are naturally occurring hollows in the ground and are usually large enough for a person to enter. They are made by a process known as "speleogenesis"! It sounds complicated, but this basically describes how caves begin and develop. They're not just small areas we can walk around in either, caves can extend deep into the Earth's crust - the deepest explored cave is the Krubera cave in Georgia and measured 7,208ft from the entrance to the bottom! Wow!
Where are caves found?
Caves are found all over the world, but the most common ones found in the UK are:
- Solutional caves - made when groundwater seeps through limestone and chalk
- Sea caves - made when waves continually hit weak cliffs, causing them to erode and wear away
A small area of the UK is made up of limestone rock, which means there are more caves there, but only a few are easy to reach so they are quite under-explored. Off the coast of Scotland is the island of Staffa, and here are several sea caves - the largest is Fingal's Cave which is over 200 ft long!
What animals live in a cave?
Animals that spend their lives in a cave are called 'troglophiles'. Examples of troglophiles include molluscs, worms, spiders, millipedes, centipedes, crustaceans, insects, fish, amphibians and reptiles. Caves are important homes for the for animals that live there. Most caves are surrounded by complete darkness, so many cave species have lost the ability of sight and nearly all cave animals have evolved to be pale in colour. Pigments that protect against the sun are useless in a cave!
No known mammals spend their entire lives just in caves; many bat species will spend daylight hours resting in caves but will leave to hunt at night.