Yeah. They show them in movies and National Geographic sometimes.
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You divide them into two categories, rather simply.
Many caves on land have "sumps" - permanently water-filled stretches of passage, usually rather like an elongated and enlarged version of the U-bend under a kitchen sink. Some cave streams emerge from sumps at their risings (springs). In a few cases, where the cave is situated at low altitude, the sump may even dip below sea-level though with no direct link to the sea. The deepest sumps in Wookey Hole, in S.W. England do that, I believe. They do so because the rock strata dip steeply, forcing passage development to follow a zig-zag course on a vertical plane.
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The other category is the cave originally formed on land at a time of low-sea-level and now below sea-level. The sign that this happened is the presence of submerged stalactites and stalagmites, which do not form underwater. Some of the largest of these are found in The Bahamas and Florida.
Underwater Spelunking
Yes. Underwater caves do exist. Many formed when sea levels were lower than they are now and were flooded when sea levels rose.
No life.
No, sorry there isn't.
You can't.
no they live in rivers
In the underwater sealed cave and in the three regi caves
yes they do but they are born in underwater caves.
Deep Sea Detectives - 2003 Secret Underwater Caves 2-9 was released on: USA: 19 July 2004
By going underwater into the muddy caves once they seek predators
true
Deep Sea Detectives - 2003 More Secret Underwater Caves 3-8 was released on: USA: 20 June 2005