Puits de la Bossée

Puits de la Bossée is a natural karst shaft (gouffre) in the commune of Saint-Pierre-de-Maillé, in the Vienne department, Nouvelle-Aquitaine. It sits in the Mazaire sector, close to where the Gartempe and Anglin rivers meet — an area riddled with limestone caves and underground galleries.

What is this place?

The shaft formed in oolitic coral limestone dating from the Upper Bathonian, part of the Jurassic period. It drops 17 metres and unfolds over roughly 260 metres of passages. A 3-metre entrance shaft opens into a large chamber that regularly hosts a bat colony. A narrow crawlway — once blocked by sediment, later cleared by cavers — leads to a chamber where medieval pottery fragments were discovered, proof that people ventured into these depths centuries ago. Further east, a gallery reaches the so-called Salle du Cervin, once piled with guano cones that have since been flattened by years of foot traffic. From the pottery chamber, another passage runs north into the "CO2 network", a section that frequently fills with carbon dioxide and is off-limits to visitors for safety reasons. The lowest point of the cave is known as the Salle du Bateau.

Why is it protected?

Puits de la Bossée ranks among the most important bat roosts in the Vienne department. Eleven bat species use it regularly or occasionally. A count carried out in August 2004 estimated a colony of Mediterranean horseshoe bats (Rhinolophus euryale) at around 1,400 individuals — an exceptionally large population by French standards. Because of this ecological value, the Mazaire sector has been classified as a ZNIEFF (a zone of recognised ecological, faunal and floral interest), and the shaft's entrance is now fenced off, with access restricted to authorised researchers and cavers.

How do you get there, and what can you actually see?

Since the cave itself is closed to casual visitors — the gate exists specifically to keep the bat colony undisturbed — what a traveller can experience is the surrounding landscape: the valley where the Gartempe and Anglin rivers converge, a stretch of countryside typical of the karst terrain that defines this part of Vienne, and the wider cluster of sites around Saint-Pierre-de-Maillé. The commune is known for a dense underground heritage: nearby stands the Grotte des Cottés, a major Palaeolithic site where Louis Pradel identified the "pointe des Cottés," a tool type that helped define the evolved Châtelperronian; the Grotte de la Marche, with further traces of prehistoric human activity, lies close by as well. The local tourist office maintains walking routes through the Gartempe valley connecting caves and châteaux, a good way to take in the geological and historical context of Puits de la Bossée without needing to step inside it.

When is the best time to visit?

Spring and autumn offer the mildest conditions for exploring the area on foot, with fewer visitors than in high summer. Keep in mind that the shaft stays closed year-round — this isn't a walk-in attraction but a protected natural site best appreciated from outside, aided by information panels and material from the local tourist office.

Frequently asked questions

Can you go inside Puits de la Bossée? No. The entrance is fenced and closed to the public. Only authorised researchers and cavers can enter, since the shaft shelters a large bat colony.

Why does this cave matter to naturalists? It hosts a colony of Mediterranean horseshoe bats numbering in the thousands (around 1,400 in 2004) along with a total of 11 bat species, making it one of the more valuable chiropteran roosts in the region.

What was found inside the cave? Fragments of medieval pottery turned up in one of its chambers, showing that people explored these passages long before modern caving.

Are there other caves worth visiting nearby? Yes. Saint-Pierre-de-Maillé is rich in underground sites — the Grotte des Cottés and Grotte de la Marche nearby are significant for Palaeolithic archaeology, and the region offers marked walking routes linking caves and châteaux along the Gartempe valley.