mammal species that live in the region include the Pyrenean desman, wildcat, dormouse or the Eurasian otter. In 2012, a paper was released documenting the presence of 187 invertebrate 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 aquatic invertebrates 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 and Euro-siberian climate regions. The surface of the natural monument is occupied by meadows, grasslands, heathlands and Iberian forests. A number of types of trees are found in these forested areas, including multiple varieties of oak, beech, hazel, poplar, alder, pine, and aspen. 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 Middle Palaeolithic up until the Middle Ages. 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 fragments. In 1986, more pottery fragments and stone tools were located, indicating a possible Neanderthal presence. In 2006, some 400 Mousterian pieces were located and the site was classified as an archaeological industry. Impressions of footprints making a round trip, accompanied by torch fragments that have been radiocarbon dated 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. 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 and the beginning of the Bronze Age. 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. See also List of longest caves References Caves of Spain Karst caves Landforms of Castile and León Protected