The Cave of Swallows, also called the Cave of the Swallows (), is an open-air

pit cave A pit cave, shaft cave or vertical cave—or often simply called a pit (in the US) and pothole or pot (in the UK); jama in Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric Alpin ...

in the municipality of

Aquismón Aquismón is a town and municipality in the Mexican state of San Luis Potosí in central Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the U ...

San Luis Potosí San Luis Potosí, officially the Free and Sovereign State of San Luis Potosí, is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 59 municipalities and is named after its capital city, San Luis Potosí. It ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. The elliptical mouth, on a slope of

karst Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...

, is wide and is undercut around all of its perimeter, widening to a room approximately wide. The floor of the cave is a freefall drop from the lowest side of the opening, with a drop from the highest side, making it the largest known cave shaft in the world, the second deepest pit in Mexico and perhaps the 11th deepest sheer drop in the world.

History

The cave has been known to the local

Huastec people The Huastec or Téenek (contraction of ''Te' Inik'', "people from here"; also known as Huaxtec, Wastek or Huastecos) are an Indigenous people of Mexico, living in the La Huasteca region including the Mexican state, states of Hidalgo (Mexico), Hid ...

since ancient times. T. R. Evans, Charles Borland, Randy Sterns, and Sid West were first shown the cave on 27 December 1966. The first documented descent was on 4 April 1967.

Geology

The cave is formed in the El Abra and Tamabra formations, limestones of Middle Cretaceous age. The cave's

speleogenesis Speleogenesis is the origin and development of caves, the primary process that determines essential features of the hydrogeology of karst and guides its evolution. It often deals with the development of caves through limestone, caused by the prese ...

is still not fully known but is a result of solutional enlargement along a vertical fracture, with subsequent vadose enlargement.

Etymology

The cave's Spanish name ''Sótano de las Golondrinas'' means ''Basement of the Swallows'', owing to the many birds which live in holes on the cave walls. These are mostly

white-collared swift The white-collared swift (''Streptoprocne zonaris'') is a species of bird in the subfamily Cypseloidinae of the swift family Apodidae. It is found in Mexico, the Greater and Lesser Antilles, Trinidad, and every mainland South American country e ...

s (''vencejos'' in Spanish) and

green parakeet The green parakeet (''Psittacara holochlorus''), green conure, or Mexican green conure is a New World parrot. As defined by the International Ornithological Committee (IOC), it is native to Mexico and southern Texas in the Rio Grande Valley. Ta ...

s (''periquillo quila''). Actual

swallow The swallows, martins, and saw-wings, or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The ...

s are in fact rarely found here. Each morning, flocks of birds exit the cave by flying in concentric circles, gaining height until they reach the entrance. In the evenings a large flock of

swifts Swift or SWIFT most commonly refers to: * SWIFT, an international organization facilitating transactions between banks ** SWIFT code * Swift (programming language) * Swift (bird), a family of birds It may also refer to: Organizations * SWIFT, a ...

circles the mouth of the cave and about once each minute, a group of perhaps 50 breaks off and heads straight down toward the opening. When they cross the edge, the birds pull in their wings and free-fall, extending their wings and pulling out of the dive when they reach the heights of their nests. Watching this has become popular with tourists.

Description

Temperatures in the cave are low.

Vegetation Vegetation is an assemblage of plants and the ground cover they provide. It is a general term, without specific reference to particular Taxon, taxa, life forms, structure, Spatial ecology, spatial extent, or any other specific Botany, botanic ...

grows thickly at the mouth, The cave floor is covered with a thick layer of debris and

guano Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...

. The fungi in the guano may cause

histoplasmosis Histoplasmosis is a fungal infection caused by ''Histoplasma capsulatum''. Symptoms of this infection vary greatly, but the disease affects primarily the lungs. Occasionally, other organs are affected; called disseminated histoplasmosis, it can ...

in humans. The cave floor and walls are inhabited by millipedes, scorpions, insects, snakes and birds. From the floor at the bottom of the main shaft, there is a series of narrow pits known as "The Crevice", totalling some , which brings the total depth of the cave to .

Extreme sports tourism

The cave is a popular

vertical caving A pit cave, shaft cave or vertical cave—or often simply called a pit (in the US) and pothole or pot (in the UK); jama in Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric Alpin ...

destination.

Caver Caving, also known as spelunking (United States and Canada) and potholing (United Kingdom and Ireland), is the recreational pastime of exploring wild cave systems (as distinguished from show caves). In contrast, speleology is the scientific ...

s anchor their ropes on the low side, where bolts have been installed in the rock and the area is clear of obstructions. Rappelling to the floor can take up to an hour. Climbing back out may take from forty minutes to more than two hours. A person without a

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

would take almost ten

second The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...

s to freefall from the mouth to the floor, hence the pit is also popular with

extreme sport Action sports, adventure sports or extreme sports are physical activity, activities perceived as involving a high degree of risk of injury or death. These activities often involve speed, height, a high level of physical exertion and highly speci ...

s enthusiasts for

BASE jumping BASE jumping () is the recreational sport of jumping from fixed objects, using a parachute to descend to the ground. BASE is an acronym that stands for four categories of fixed objects from which one can jump: buildings, antenna (radio), antenna ...

Notes

References

External links

* {{DEFAULTSORT:Cave Of Swallows Caves of Mexico Limestone caves Landforms of San Luis Potosí Wild caves Sinkholes of Mexico Karst formations of Mexico