Overview
The challenges of the sport depend on the cave being visited, but often include the negotiation of pitches, squeezes, and water (though actual cave diving is a separate sub-specialty undertaken only by very few cavers). Climbing or crawling is often necessary, and ropes are used extensively for safety of the negotiation of particularly steep or slippery passages.
Caving is often undertaken for the enjoyment of the activity or for physical exercise, as well as original exploration, similar to mountaineering or diving. Physical or biological science is also an important goal for some cavers. Virgin cave systems comprise some of the last unexplored regions on Earth and much effort is put into trying to locate and enter them. In well-explored regions (such as most first-world countries), the most accessible caves have already been explored, and gaining access to new caves often requires digging or diving.
Caves have been explored out of necessity (for shelter from the elements or from enemies), out of curiosity or for mystical reasons for thousands of years. However, only in the last century or two has the activity developed into a sophisticated, athletic pastime. In recent decades caving has changed considerably due to the availability of modern protective wear and equipment. It has recently come to be known as an "extreme sport" by some (though not commonly considered as such by its practitioners, who may dislike the term for its perceived connotation of disregard for safety).
Many of the skills of caving can also be used in the nature activities of mine exploration and urban exploration.
Naming issues
Clay Perry — an American caver of the 1940s — wrote about a group of men and boys who explored and studied caves throughout New England. This group referred to themselves as spelunkers. This is regarded as the first use of the word in the Americas. Throughout the 1950s, spelunking was the general term used for exploring caves in US English. It was used freely, without any positive or negative connotations, although only rarely outside the US.
In the 1960s, the terms "spelunking" and "spelunker" began to be considered déclassé among experienced enthusiasts. They began to convey the idea of inexperienced cavers, using unreliable light sources and cotton clothing. In 1985, Steve Knutson (editor of American Caving Accidents) made the following distinction:
...Note that I use the term 'spelunker' to denote someone untrained and unknowledgeable in current exploration techniques, and 'caver' for those who are.
This sentiment is exemplified by bumper stickers and t-shirts displayed by many cavers: "Cavers rescue spelunkers".
Potholing refers to the act of exploring potholes, a word originating in the north of England for predominantly vertical caves. The term is often used as a synonym for caving, and outside the caving world there is a general impression that potholing is a more "extreme" version of caving.
History
Caving has been pioneered by Édouard-Alfred Martel who first achieved the descent and exploration of the Gouffre de Padirac, France as early as 1889 and the first complete descent of a 110 metre wet vertical shaft at Gaping Gill, in Yorkshire, England in 1895. He developed his own techniques based on ropes and metallic ladders. Édouard-Alfred Martel visited Kentucky and notably Mammoth Cave National Park in October 1912. Famous US caver Floyd Collins made in the 1920's important explorations in that area. In the 1930's, as caving became increasingly popular, small exploration teams both in the Alps and in the karstic high plateaus of southwest France (Causses and Pyrenees) transformed cave exploration in both a scientific and recreational activity. Robert de Joly, Guy de Lavaur and Norbert Casteret were prominent figures of that time. They surveyed mostly caves in Southwest France. During WWII, an alpine team composed of Pierre Chevalier, Fernand Petzl, Charles Petit-Didier and others explored the Dent de Crolles cave system near Grenoble, France which became the deepest explored cave in the world (-658m) at that time. The lack of available equipment during the war forced Pierre Chevalier and the rest of the team to develop their own equipment, leading to technical innovation. The scaling-pole (1940), nylon ropes (1942), use of explosives in caves (1947) and mechanical rope-ascenders (Henri Brenot's "monkeys", first used by Chevalier and Brenot in a cave in 1934) can be directly directly associated to the exploration of the Dent de Crolles cave system. American caver Bill Cuddington, known as "Vertical Bill" developed in US the single rope technique (SRT) in the late 1950s. In 1958, two Swiss alpinists, Juesi and Marti teamed together, creating the first rope ascender known as the Jumar. In 1968 Bruno Dressler asked Petzl, who worked as a metals machinist, to build a rope-ascending tool, today known as the Petzl Croll, that he had developed by adapting the Jumar to the specificity of Pit caving. Pursuiving these developments, Fernand Petzl started in the 1970s a small caving equipment manufacturing company Petzl, which is today a world leader in equipment for both caving, mountaineering and at-height safety in civil engineering. The development of the rappel rack and the evolution of mechanical ascension systems, notably helped extend the practice and safety of pit exploration to a larger venue of established cavers. Practice and equipment
Hard hats are worn to protect the head from bumps and falling rocks. The caver's primary light source is usually mounted on the helmet in order to keep the hands free. Electric lights are most common, with halogen lamps being standard and white LEDs as the new competing technology. Many cavers carry two or more sources of light - one as primary and the others as backup in case the first fails. More often than not, a second light will be mounted to the helmet for quick transition if the primary fails. Carbide lamps systems are an older form of illumination, inspired by miner's equipment, and are still used by some cavers.
The type of clothes worn underground varies according to the environment of the cave being explored, and the local culture. In cold caves, the caver may wear a warm base layer that retains its insulating properties when wet, such as a fleece ("furry") suit and/or polypropylene underwear, and an oversuit of hard-wearing (e.g., cordura) and/or waterproof (e.g., PVC) material. Lighter clothing may be worn in warm caves, particularly if the cave is dry, and in tropical caves thin polypropylene clothing is used, to provide some abrasion protection whilst remaining as cool as possible. Wetsuits may be worn if the cave is particularly wet or involves stream passages. On the feet boots are worn - hiking-style boots in drier caves, or rubber boots (such as wellies) often with neoprene socks ("wetsocks") in wetter caves. Knee-pads (and sometimes elbow-pads) are popular for protecting joints during crawls. Depending on the nature of the cave, gloves are sometimes worn to protect the hands against abrasion and/or cold. In pristine areas and for restoration, clean oversuits and powder-free, non-latex surgical gloves are used to protect the cave itself from contaminants.
Ropes are used for descending or ascending pitches ("Single Rope Technique") or for protection. Knots commonly used in caving are the figure-of-eight- (or figure-of-nine-) loop, bowline, alpine butterfly, and Italian hitch. Ropes are usually rigged using bolts, slings, and carabiners. In some cases cavers may choose to bring and use a flexible metal ladder.
In addition to the equipment already described, cavers frequently carry packs containing first-aid kits, emergency equipment, and food. Containers for securely transporting urine are also commonly carried. On longer trips, containers for securely transporting faeces out of the cave are carried.
During very long trips, it may be necessary to camp in the cave. This necessitates the caver carrying sleeping and cooking equipment.
Safety
Main article: Cave rescue
Caves can be dangerous places; hypothermia, falling, flooding, and physical exhaustion are the main risks. Rescuing people from underground is difficult and time-consuming, and requires special skills, training, and equipment. Full-scale cave rescues often involve the efforts of dozens of rescue workers (often other long-time cavers who have participated in specialised courses, as normal rescue staff are not sufficiently experienced in cave environments), who may themselves be put in jeopardy in effecting the rescue. This said, caving is not necessarily a high-risk sport (especially if it does not involve difficult climbs or diving). As in all physical sports, knowing one's limitations is key.
The risks are minimised by a number of techniques:
Checking that there is no danger of flooding during the expedition. Rainwater funneled underground can flood a cave very quickly, trapping people in cut-off passages and drowning them. After falling, this is the most likely fatal accident in caving.
Using teams of several, preferably at least of four cavers. If an injury occurs, one caver stays with the injured person while the other two go out for help, providing assistance to each other on their way out.
Notifying people outside the cave as to the intended return time. After an appropriate delay without a return, these will then organise a search party (usually made up by other cavers trained in cave rescues, as even professional emergency personnel are unlikely to have the skills to effect a rescue in difficult conditions).
Use of helmet-mounted lights (hands-free) with extra batteries. American cavers recommend a minimum of three independent sources of light per person, but two lights is common practice amongst European cavers.
Sturdy clothing and footwear, as well as a helmet, are necessary to reduce the impact of abrasions, falls, and falling objects. Synthetic fibers and woolens, which dry quickly, shed water, and are warm when wet, are vastly preferred to cotton materials, which retain water and increase the risk of hypothermia. It is also helpful to have several layers of clothing, which can be shed (and stored in the pack) or added as needed. In watery cave passages, polypropylene thermal underwear or wetsuits may be required to avoid hypothermia.
Cave passages look different from different directions. In long or complex caves, even experienced cavers can become lost. To reduce the risk of becoming lost, it is necessary to memorise the appearance of key navigational points in the cave as they are passed by the exploring party. Each member of a cave party shares responsibility for being able to remember the route out of the cave. In some caves it may be acceptable to mark a small number of key junctions with small stacks or "cairns" of rocks, or to leave a non-permanent mark such as high-visibility flagging tape tied to a projection.
Vertical caving using ladders or SRT (Single Rope Technique) to avoid the need for climbing passages that are too difficult. SRT however is a complex skill and requires proper training before use underground and needs well-maintained equipment. Some drops that are abseiled down may be as deep as several hundred meters (for example Harwood Hole).
Cave conservation
Many cave environments are very fragile. Many speleothems can be damaged by even the slightest touch and some by impacts as slight as a breath.
Pollution is also of concern. Since water that flows through a cave eventually comes out in streams and rivers, any pollution may ultimately end up in someone's drinking water, and can even seriously affect the surface environment, as well. Even minor pollution such as dropping organic material can have a dramatic effect on the cave biota.
Cave-dwelling species are also very fragile, and often, a particular species found in a cave may live within that cave alone, and be found nowhere else in the world. Cave-dwelling species are accustomed to a near-constant climate of temperature and humidity, and any disturbance can be disruptive to the species' life cycles. Though cave wildlife may not always be immediately visible, it is typically nonetheless present in most caves.
Bats are one such fragile species of cave-dwelling animal. Despite their often frightening reputation in fiction and in the movies, bats generally have more to fear from humans than vice-versa. Bats can be beneficial to humans in many ways, especially through their important ecological role in reducing insect pest populations, and pollination of plant species. Bats which hibernate are most vulnerable during the winter season, when no food supply exists on the surface to replenish the bat's store of energy should it be awakened from hibernation. Bats which migrate are most sensitive during the summer months when they are raising their young. For these reasons, visiting caves inhabited by hibernating bats is discouraged during cold months; and visiting caves inhabited by migratory bats is discouraged during the warmer months when they are most sensitive and vulnerable.
Some cave passages may be marked with flagging tape or other indicators to show biologically, aesthetically, or archaeologically sensitive areas. Marked paths may show ways around notably fragile areas such as a pristine floor of sand or silt which may be thousands of years old, dating from the last time water flowed through the cave. Such deposits may easily be spoiled forever by a single misplaced step. Active formations such as flowstone can be similarly marred with a muddy footprint or handprint, and ancient human artifacts, such as fiber products, may even crumble to dust under the touch of any but the most careful archaeologist.
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