A spelunker is a person who explores caves as a hobby. Two other terms applied to those who partake in cave exploration are caver and speleologist. However, the latter two terms are generally reserved for those with extensive training and education in the science of caving. Spelunkers are usually amateurs who don't follow any specific guidelines for traversing the passages of caves to retrieve data for scientific study. Drawn to the mystery of the unexplored and uncharted, spelunkers seek caves for their own pleasure and not necessarily with any specific goals in mind.
Many who are interested in becoming a spelunker join clubs or groups organized by more experienced cave explorers, such as the National Speleological Society (NSS). The NSS organizes caving clubs that promote the preservation of caves, interest in the science of caving, and advancement in the study of caves. These clubs also plan caving trips that allow for safer exploration, as a lone spelunker would be taking a huge risk. It is always best to have a group large enough to allow for some to remain outside the cave, lest the participants inside the cave run into trouble and require a rescue.
Safety is a primary concern for spelunkers. The biggest risks are falling, being hit by a falling object, and hypothermia. Caves are dark and often damp, making surfaces slippery and range of vision limited. This means a spelunker must move carefully and deliberately and ensure proper footwear and gear is worn at all times. A helmet is required to reduce the risk of injury from falling objects, and warm clothing is essential in case a spelunker gets separated from the group and stuck in a cold cave for a longer time than originally anticipated. Spelunkers should also be sure to bring a first aid kit, food, water, and light.
Some of the basic tenets of safe and responsible cave exploration are to form groups of four to six spelunkers, establish a time limit before entering a cave, and tell additional parties about the caving trip. Spelunkers must be in relatively good shape as many caves require climbing, squeezing through tight passages, and sometimes using ropes to descend into pits. Novice spelunkers should always include more experienced cavers in the group and start with well known caves that are less likely to have surprise obstacles. Most importantly, new spelunkers should remember to stay with the group at all times.