The caves were discovered by Jack while he was chasing the Man in Black disguised as his father. Due to its running supply of fresh water, it became, for a time, a home to the middle section survivors. According to Jack, it provided a number of benefits:
- Location one mile from the beach camp
- Unlimited supply of fresh water
- Tree canopy which kept the temperature down
- Shielding from the sun
- Narrow openings, which meant better protection against predators
Jacob and the Man in Black's Mother
The adoptive mother of Jacob and the Man in Black lived in the cave and raised them there. It was also the place where the Man in Black killed his mother and where Jacob laid his mother and the Man in Black to rest, later to be known as Adam and Eve. ("Across the Sea")
Adam & Eve
The remains of the Man in Black and his adoptive mother, which were given the names Adam and Eve by Locke, were found in the cave and had been dead at least 40-50 years according to the deterioration of their clothing. They were carrying one black and one white stone, which were placed there by Jacob. Jack took these stones and didn't mention them when Locke asked what had been discovered. ("House of the Rising Sun") ("Across the Sea")
There were seen again by Jack and Hugo three years later, though they had changed positions and now both skeletons were placed side-by-side, and possibly in a different part of the caves, closer to Jack's father's coffin.
The caves and the survivors
The caves were first discovered by the survivors when Jack was chasing what he thought was his dead father who was later revealed to be the Man in Black. Part of the plane's cargo compartment also landed in the caves, along with various objects that were in it, including luggage, a coffin, and dolls. After Jack discovered the caves, he decided it was a good place to set up camp, due to its running supply of fresh water. However this caused a disagreement within the Losties mainly because it would be harder for them to be spotted by potential rescuers flying in planes. About half of the group moved to the caves.
Many situations occurred at the caves. Jack and Charlie were in a cave-in, after a few days living in the caves, prompting Michael to check the structural integrity of the rest of the caves. Also Boone ultimately died here after sustaining fatal wounds while exploring the drug smugglers' plane.
The caves were eventually abandoned once the hatch was opened (last seen in "Adrift"). Presumably, the Swan was closer to camp and it also had a sink, so trekking to the caves may not have been as practical. However, after the destruction of the Swan in "Live Together, Die Alone", the caves did not appear as a source of water or protection for the crash survivors.
There was some disagreement among the survivors as to whether it was better to camp in the caves or on the beach.
After Jack discovered the caves, he decided it would be a good place to set up camp. There was a contingent that disagreed, mainly because it would be harder for potential rescuers flying in planes to spot them. Among those that disagreed with Jack were Kate, Sayid, and Sawyer.
- This argument seemed to have been settled in favor of the beach camp after the discovery of the Swan.
- Bernard attempted to use lava rocks to create a signal visible from the air; this was only possible on the beach. ("S.O.S.")
- Arzt opposed the move to the caves, until he was spooked by the Monster ("Arzt & Crafts")
- Shannon did not want to move to the caves because Claire was attacked. (She called them the "rape caves"). Boone stayed at the beach to be with Shannon.
In the video game Lost: Via Domus, a different set caves were seen in greater detail. The caves as seen in Lost: Via Domus are considered a canonical addition to the show. The caves were explored in further detail by Elliott Maslow and John Locke. Elliott explored the caves on Day 2 and Day 18 on the Island. When Elliott first explored the caves, he discovered that they were filled with deep fissures, bats, and a dead polar bear. The Monster could also be heard inside the caves. Elliott also saw visions of Lisa inside the caves. ("A New Day")
Locke led Elliott to the caves and told him that he would give him the battery if he entered the caves. Elliott explored the caves and followed Lisa to a waterfall cavern. He discovered a corpse that was holding a compass. The compass had Via Domus inscribed on it, which means The Way Home. ("Via Domus")