Are there any deadly creatures in underground caves that could cause immediate harm to humans? Say something like a large snake or crocodiles? Has a cave diver ever went cave diving and bumped into such creatures?
Snakes and scorpions are known to frequent above ground caves. http://www.msha.gov/kids/abandon/under.htm
Bats can have rabies. Animals can eat rope.
watch out for the red or purple ampersands, they’re deadly!
It depends on the location and environment of the cave. Most caves with any substantial length don’t have enough of a food chain to support anything that could be classified as directly dangerous to a person. Scorpions and such would more likely be temporary visitors rather than permanent residents, and would be situated relatively close to the entrance.
If it’s pitch dark, you are likely to be eaten by a grue.
Mostly it’s the cave hiding felons you need to worry about. They don’t actually live there, but then, neither do you.
Tris
Gollum.
What about Morloks?
Quite dangerous, even more so if they manage to get a hold of some tree-of-life.
Well, there’s those things in the movie The Descent. They get especially nasty because there’s nothing for them down there to eat – they have to wait for the occasional spelunker, and then they’re all over them.
Morlocks don’t scare me. Sleestaks on the other hand…
So, nothing grows, absent of light, therefore there is nothing to eat that nothing?
No, there are creatures living in caves, and adapted to this environment (crustaceans, inects, etc…). The first names coming to my mind is the Niphargus, looking like a small shrimp, and the proteus. This one, I believe, is at the top of the food chain in caves, meaning that you’re extremely unlikely to be harmed by any cave-dweeler.
Here’s the more general wikipedia’s article about troglobites (animals fully adapted to life in caves), explaining too the differences with the two other categories of subteranean life (respectively creatures who can live both in caves and in “normal” environments, and creatures only using caves as temporary refuges (the most obvious being bats).
There are things that live in caves, but, absent light or some other large energy input, it’s probably not going to get very big. Big things tend to live part-time in caves, getting their energy input from stuff outside the cave, and ultimately from the sun. Hence my skepticism about mutant human underground dwellers.
Your correct that nothing grows, but in many caves there’s organic detritus that comes from the surface. It’s not a lot, but enough to support a small community. At one extreme, bats sleep in caves but hunt outdoors, and when they return their droppings become mountains of bat guano. There are whole little ecosystems that depend on that guano.
Many of these permanent cave-dwellers live in underground streams which carry organic sediments from the surface. Bacteria and other microorganisms eat these sediments. Small filter feeders eat the microbes, and in turn are food for the top predators like salamanders and crayfish.
There are known to exist bacteria whose energy is ultimately derived from radioactive decay rather than sunlight, which is pretty damn awesome. However, I’m pretty sure that anything larger ultimately derives its energy from sunlight.
I think it would be interesting to raise some crocodiles in a deep cave somewhere and every so often throw them some food. It should make for an interesting tourist attraction.
I think I’ve seen cave pythons on one of those “Extreme Adventurer” shows. One guy got his leg bitten while trying to find one of them…
Ah, but the cannibalistic humanoid underground dwellers tend to come out of their caves under the cover of night to procure protein.