Cueva del Viento

Biology

Cueva del Viento is home to significant biological treasures and is a unique place for studying animals that are now locally extinct on the island of Tenerife.

The underground environment is characterised by total darkness, very high humidity levels, a constant temperature and almost absolute stillness. No light, no green plants and no organic matter, so what little food there is has to come from outside. Roots that penetrate from above through cracks, animals that accidentally enter the cave or sediment carried by the water that percolates through the earth.

In order to survive in these conditions cave species have had to evolve and produce adaptations that differentiate them from their aboveground relatives. These modifications arise as certain organs become unnecessary for the organism and it adapts to expend less energy in this dark world. An example is reproduction in cave species, which produce fewer eggs but provide them with greater reserves to ensure the survival of the young in an environment with so little food.

The study of these adaptations has its own particular history in Cueva del Viento. Already, in the 1970s, experts were theorising the existence of troglobite insects (cave-dwelling animals), although zoologists had never visited the cave. Biological studies were first carried out thanks to the discovery of subfossil bones of the now extinct giant lizard, Gallotia goliath, and giant rat, Canariomys bravoi.

This finding was followed by the discovery of various troglobitic species that were hitherto unknown in the Canary Islands, including the eyeless cockroach Loboptera subterranea and the ground beetles Wolltinerfia martini and Wolltinerfia tenerifae, which were new to science. This phenomenon is common in caves of this type, and the animals that have adapted to life in them are unable to survive outside of that environment.

In 1982, a group of biologists from the University of La Laguna conducted a thorough study of the cave. They found that saprophages (or detritivores, meaning they feed on detritus) were by far the most abundant creatures. This study was carried out only on the highest level, specifically in the Belén, Breveritas Superior, Breveritas Inferior and Breveritas Profunda galleries. They discovered 37 animal species, of which 9 were troglobites. In 1987 an extremely thorough, detailed and rigorous new study was carried out, leading to the discovery of more species, bringing the total to 43.

In this type of cave animals live by the maxim “adapt or die” and quite incredible changes come about, such as body discoloration or vision loss. In some cases, such as that of the woodlouse Venezillo tenerifensis, pigmentation disappears altogether, as there is no need for it without sunlight.

As it is not possible to see in pitch black darkness, sometimes their eyes atrophy and even disappear entirely. This is the case of a type of cave cockroach (Loboptera troglobia) which has lost its sight; moreover, its skin is sensitive to light, so it avoids lit areas.

Other animals develop other senses to compensate their blindness. This is the case of the beetle Domene vulcanica whose long antennae gives it a heightened sense of smell and a delicate sense of touch that make up for its lack of eyesight, and its streamlined legs and body help it on its endless march in search of scarce food. Moreover, because food is so scarce in cave environments, these animals can fast for months thanks to their slow metabolism, as is the case of the cave-dwelling spider Canarionesticus quadridentatus.

Species for which subfossils have been found in Cueva del Viento include: the giant lizard, Gallotia goliath, and the giant rat, Canariomys bravoi, both of which are exclusive to Tenerife; the long-legged bunting (Emberiza alcoveri), only ever found in Cueva del Viento; the extinct Canary Islands quail (Coturnix gomerae), which has also been found on La Gomera; and the red-billed chough (Pyrrhocorax pyrrhocorax) which currently only lives on La Palma.

Vegetation occupies three sections: the external zone, with vascular plants and some ferns and lichens; the entrance zone, which begins at that point the rain does not directly reach, but does receives light and contains mainly mosses and lichens; and the transition zone, which receives indirect light, where cyanobacteria and lichens are found.