Ojo Guareña is a karst complex located in the

Cantabrian Mountains , etymology=Named after the Cantabri , photo=Cordillera Cantábrica vista desde el Castro Valnera.jpg , photo_caption=Cantabrian Mountains parallel to the Cantabrian Sea seen from Castro Valnera in an east-west direction. In the background, ...

Castile and Leon Castile, Castille or Castilla may refer to: Places Spain *Castile (historical region), a vaguely defined historical region of Spain covering most of Castile and León, all of the Community of Madrid and most of Castilla–La Mancha *Kingdom of ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

, declared a

natural monument A natural monument is a natural or natural/cultural feature of outstanding or unique value because of its inherent rarity, representative of aesthetic qualities or cultural significance. Under World Commission on Protected Areas guidelines, na ...

by the government of Castile and Leon in 1996. It is composed of over of galleries and passages within an area of some . The limestone formation containing the system is approximately thick and sits on a massive water-resistant layer of marl. The caves were formed in the

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...

sometime within the Coniacian Age. Ojo Guareña was considered the greatest karst system of the

Iberian Peninsula The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, def ...

until 2009, when a significant length of new passages was discovered in the Mortillano system. It is also the 24th longest cave system. Archaeological findings in the area indicate that various caves in the Ojo Guareña system were used by humans as early as the

Middle Palaeolithic The Middle Paleolithic (or Middle Palaeolithic) is the second subdivision of the Paleolithic or Old Stone Age as it is understood in Europe, Africa and Asia. The term Middle Stone Age is used as an equivalent or a synonym for the Middle Pale ...

up until the

Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...

. Scientific exploration has also discovered the presence of over 180 species of invertebrates in the complex. Tourist access to the caverns is permitted, and there is a visitor's centre located in .

Features

The karst complex of Ojo Guareña consists of a massive network of over galleries and cavities, not all of which are connected, occupying an area of about 13,000 ha. The main network consists of fourteen caves that are connected with each other over six different levels of the system. The most prominent entry point is at Palomera Cave. Ojo Guareña was formed by the erosive action of the Guareña and Trema rivers, in addition to the Villamartín stream. These bodies of water run through the lower galleries for most of the year, although during flood season it is possible for the water to enter the higher galleries. Eventually, they return to the outside through

karst spring A karst spring or karstic spring is a spring (outflow of groundwater) that is part of a karst hydrological system. Description Because of their often conical or inverted bowl shape, karst springs are also known in German-speaking lands as a ''T ...

s at Trema, Torquilla, Torcón and Torcona, located on a lower section of Trema River. The groundwater runs through Ojo Guareña at a speed of 1.5–5 km per day, depending on whether the measurement is made during the drier summer or the flood season. The groundwater feeds an

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characteris ...

located in the hinge of the area's syncline fold.

Flora and fauna

A number of birds live in the area surrounding the cave complex, including the

golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of ...

short-toed snake eagle The short-toed snake eagle (''Circaetus gallicus''), also known as the short-toed eagle, is a medium-sized bird of prey in the family Accipitridae, which also includes many other diurnal raptors such as kites, buzzards and harriers. The genus n ...

Egyptian vulture The Egyptian vulture (''Neophron percnopterus''), also called the white scavenger vulture or pharaoh's chicken, is a small Old World vulture and the only member of the genus ''Neophron''. It is widely distributed from the Iberian Peninsula and ...

, Eurasian sparrowhawk,

Eurasian eagle-owl The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, and femal ...

griffon vulture The Eurasian griffon vulture (''Gyps fulvus'') is a large Old World vulture in the bird of prey family Accipitridae. It may also be known as the Griffon vulture, though it may be used for the genus as a whole. It is not to be confused with Rü ...

tawny owl The tawny owl (''Strix aluco''), also called the brown owl, is commonly found in woodlands across Europe to western Siberia, and has seven recognized subspecies. It is a stocky, medium-sized owl, whose underparts are pale with dark streaks, a ...

, and the peregrine falcon. Inside the caves there are several species of

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...

s, such as the cave bat,

greater horseshoe bat The greater horseshoe bat (''Rhinolophus ferrumequinum'') is an insectivorous bat of the genus '' Rhinolophus''. Its distribution covers Europe, Northern Africa, Central Asia and Eastern Asia. It is the largest of the horseshoe bats in Europe an ...

, lesser horseshoe bat, and Geoffroy's bat. Other mammal species that live in the region include the

Pyrenean desman The Pyrenean desman also called Iberian desman (''Galemys pyrenaicus'') is a small semiaquatic, globally threatened mammal related to moles and shrews, and, along with the Russian desman (''Desmana moschata''), is one of the two extant members ...

wildcat The wildcat is a species complex comprising two small wild cat species: the European wildcat (''Felis silvestris'') and the African wildcat (''F. lybica''). The European wildcat inhabits forests in Europe, Anatolia and the Caucasus, while th ...

dormouse A dormouse is a rodent of the family Gliridae (this family is also variously called Myoxidae or Muscardinidae by different taxonomists). Dormice are nocturnal animals found in Africa, Asia, and Europe. They are named for their long, dormant hibe ...

or the

Eurasian otter The Eurasian otter (''Lutra lutra''), also known as the European otter, Eurasian river otter, common otter, and Old World otter, is a semiaquatic mammal native to Eurasia. The most widely distributed member of the otter subfamily (Lutrinae) of th ...

. In 2012, a paper was released documenting the presence of 187

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

species in Ojo Guareña, belonging to a variety of phyla. 32 of them were entirely new to science. Of the more than 200

cave-dwelling A cave dweller, or troglodyte, is a human being who inhabits a cave or the area beneath the overhanging rocks of a cliff. Prehistory Some prehistoric humans were cave dwellers, but most were not (''see'' ''Homo'' and Human evolution). Suc ...

aquatic

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...

that are known in Spain, more than a quarter of them were discovered in Ojo Guareña. The vegetation in the Ojo Guareña area is very diverse due to its location in a transition zone between the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western Europe, Western and Southern Europe and Anatolia, on the south by North Africa ...

and Euro-siberian climate regions. The surface of the natural monument is occupied by

meadow A meadow ( ) is an open habitat, or field, vegetated by grasses, herbs, and other non- woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows may be naturally occurring or arti ...

grassland A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...

heath A heath () is a shrubland habitat found mainly on free-draining infertile, acidic soils and characterised by open, low-growing woody vegetation. Moorland is generally related to high-ground heaths with—especially in Great Britain—a cooler a ...

lands and Iberian forests. A number of types of trees are found in these forested areas, including multiple varieties of

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

, beech, hazel, poplar,

alder Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

, and

aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the '' Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (Chin ...

Archaeology

Evidence has been found to indicate the presence of human beings in and around the caves of Ojo Guareña from at least as early as the

up until the

Palaeolithic

The oldest signs of human presence, including cave paintings and tools, in the complex of Ojo Guareña are in the cave of Prado Vargas. Excavations in 1973 located prehistoric

pottery Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and ...

fragments. In 1986, more pottery fragments and stone tools were located, indicating a possible

Neanderthal Neanderthals (, also ''Homo neanderthalensis'' and erroneously ''Homo sapiens neanderthalensis''), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. While the ...

presence. In 2006, some 400

Mousterian The Mousterian (or Mode III) is an archaeological industry of stone tools, associated primarily with the Neanderthals in Europe, and to the earliest anatomically modern humans in North Africa and West Asia. The Mousterian largely defines the l ...

pieces were located and the site was classified as an

archaeological industry :''Not to be confused with industrial archaeology, the archaeology of (modern) industrial sites.'' In the archaeology of the Stone Age, an industry or technocomplex is a typological classification of stone tools. An industry consists of a nu ...

. Impressions of footprints making a round trip, accompanied by torch fragments that have been

radiocarbon dated Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was dev ...

to as old as 15,600 years, indicate that the cave has been in use for millennia.

Neolithic and Bronze Age

In the Cave of Kaite, paintings have been found that appear to represent

deer Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the re ...

. On the walls and the vault of the ''Sala de la Fuente'', or Fountain Room, are paintings that depict people, animal forms, and geometric drawings. These images span a period of time between the late

Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several p ...

and the beginning of the

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...

Protected status

On March 14, 1996, Decrees 60/1996 and 61/1996 were issued, approving the Natural Resource Management Plan for Ojo Guareña (Burgos) and declaring the official status of Ojo Guareña as Natural Monument of Ojo Guareña (Burgos). Decree 174/1998, of September 3, 1998, regulates the composition of the Governing Board of the Ojo Guareña Natural Monument.

References

{{DEFAULTSORT:Ojo Guareña Caves of Spain Karst caves Landforms of Castile and León Protected areas of Castile and León Mousterian