 For obvious reasons, vertical caving is more dangerous than "horizontal caving".Vertical caving requires the intimate understanding of ropes, knots, anchors, rappelling devices and ascending systems.Veteran cavers typically are knowledgeable in self rescue techniques including change-overs (the act of switching from rappel to climb while on rope) and pick-offs (the act of rescuing a stranded caver from his rope and returning him to the ground).