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From cave bears to the gold rush

Grotte del Bandito Nature Reserve

One of the entrances to the karst system (G. Bernardi/PNAM).

In short
The crystalline massif of Argentera is embraced by arms of sedimentary rock which cover the lower Valle Gesso: these were sea beds that became limestones and dolomites. These are relatively "softer" more permeable rocks, compared with the peaks at the top of the valley. Over the millennia water has worked its way through cracks and crevices in these rocks, eroding tunnels and passages. The most important underground network in the valley is that at Grotte del Bandito which opens onto the river Gesso, in the municipality of Roaschia. Remains of the ancient cave bear Ursus spelaeus were found here. It was also a site where the valley people spent a long time digging for gold. Bat colonies spend the winter in the cave taking advantage of the constant climate. Bats should never be disturbed whilst in hibernation, as it can kill them. There are invertebrates here that are perfectly adapted to the underground environment. These caves, thanks to their environmental and archeological interest, are part of a Nature Reserve included in the SCI IT1160056 “Alpi Marittime": they are protected and access is limited.

How the Grotte del Bandito were formed
About 200,000 years ago, in the third ice-age, also known as the Riss ice-age, the Valle Gesso was covered by two large glacial tongues: the first, the Entracque glacier, was formed by the glaciers of Barra, Rovine and Trinità; the second called the Valdieri glacier, was formed by the union of the Valletta and Valasco glaciers with that of Meris. The two main glacial tongues met upstream of Valdieri forming the huge Gesso glacier, about 300 metres thick and almost two kilometres wide reaching down to the narrowing in the valley below Andonno. During the last ice-age, the Würm glaciation, the two tongues remained separate, the detritus they brought down is still visible in the moraine deposits at Tetto Bandito and San Lorenzo di Valdieri, easily identifiable from the main road, and in the deposits at Esterate and the Polveriera. In more recent times underground springs, like the Dragonera at Roaschia or the Bandito spring have eroded tunnels and passages forming an intricate network of karst caves, of which the Grotta del Bandito is one.

The bears are coming!
This underground network has been studied since the nineteenth century for its rich fossil remains, in particular the cave bear bones. (Ursus spelaeus), a species of bear that became extinct in the last ice-age, lived in Valle Gesso and numerous other caves in the Cuneo area (grotta del Caudano - Val Maudagna -, grotta di Bossea - Val Corsaglia -, karst caves in Val Casotto, Valdinferno-Val Tanaro and in Val Pennavaire) from 66,000 to 30,000 thousand years ago. Cave bears were animals of considerable size, about a third bigger than our brown bear: the largest could be up to three and a half metres tall standing on their hind legs, about a metre and a half at the shoulder. Their weight is estimated as being up to a tonne. These figures make the cave bear amongst the largest carnivores ever to walk the Earth.
They sheltered in caves, usually in the inner parts to hibernate or give birth to their cubs. From their teeth and the way they are worn we can gain precious information about their diet: analysis of these features has lead scientists to believe that Ursus spelaeus was omnivorous and maybe more vegetarian than the modern-day brown bear. Their extinction seems linked to a dramatic change in climate and the consequent changes in the environment that occurred at the end of the Würm glaciation, the last great glacial expansion, about 15,000 years ago: large numbers of animal bones were deposited on the floor of the Grotte del Bandito. When Gesso flooded the water flowed into the underground caves and passages, and the alluvium it brought covered the bear skeletons helping to fossilize them.

Not just bears...
The caves at the grotte del Bandito were not only shelters for large plantigrades. In protohistoric times they were used by humans, as was shown by a chance finding in 1967, in the west cave, of a bronze knife probably of Villanovan (Bologna) make, datable to the eighth century BC. It is an extremely important find because it is an crucial clue to the trade links between the Emilia-Romagna area and the mountain passes of the Western Alps, via the Tanaro route. The marks and signatures on the sides of the caves show that they were in use in historic times too, a destination and shelter for all types of humanity over the ages: explorers, potholers, bandits, lovers and partisans all have left their mark on the walls of these grottoes.

Digging to get rich and digging to discover
At the end of the nineteenth century some branches of the cave were prospected for gold, this frenetic digging destroyed many fossils. The gold rush was soon over because of the poor returns and the difficulty in sieving. Documents held in the Museum in Cuneo show that early in the twentieth century the numerous bear bones found around the caves were used by the children of Roaschia who made "trains" and other toys out of bones! Further excavations in the twentieth century brought to light the remains of other animals besides bears, some of which were connected to the use of the caves by prehistoric groups. In 1967 a bronze knife was found, attributed to the early Iron Age. In recent years, following studies by Livio Mano and the research by Professor Giulio Pavia's team from Turin University in 2001-2002, more information concerning cave bears has been obtained. The latest studies, carried out by Dr. Marta Zunino and Prof. Giulio Pavia have given us a complete picture of the prehistoric inhabitants of these caves.

Download the study notes The Ursus speleaus deposit in Grotta del bandito: stratigraphic,taphonomic and biochronlogic considerations by Prof. Luigi Pavia and Dr. Marta Zunino published in the Rendiconto della Società paleontologica italiana.

Rich and interesting animal life, a site to protect
Today this site is of particular biological interest, as there are several rare arthropods and amphibians. These caves are locus typicus for Eukoenenia spelaea and are the ideal habitat for the Diplopod Plectogona vignai, the Chilopod Lithobius scotophilus, the Carabid Duvalius carantii, a Trechinae, the troglophile Carabid Sphodropsis ghilianii is commonly found here on the gravel floor of the cavern, Dolichopoda ligustica on the walls, with Limonia nubeculosa and Lepidoptera of the Parietal Association.
On the ceiling around the numerous openings you can find troglophile spiders such as Meta menardi (subtroglophile) and Nesticus eremita (eutroglophile). In the same zones, but on the ground or walls you may see the North-West Italian Cave Salamander (Speleomantes strinatii). In addition to these, 13 species of bat, including Rhinolophus ferrumequinum,Rhinolophus hipposideros, Barbastella barbastellus, Myotis myotis, Myotis emarginatus, Myotis nattereri, Nyctalus leisleri, and Plecotus auritus.

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