Right from the start of the investigations, the possibility of several entrances to the cave was examined. The entrance through the current porch on the cliff of the Cirque d'Estre was evident because the scree cone is clearly visible both from inside and outside the cave. The hypothesis was considered of a second entrance at the end of the Gallery of the Crosshatching and/or the End Chamber.
This hypothesis was justified by the concentration of drawings on the panels of the End Chamber and by the large number of hearths, implying the transport of bundles of sticks and branches over several hundred metres. Following two years of investigations inside the cave combined with surveying on the outside, it appears that there was only a single entrance, that of the porch in the cliff of the Cirque d'Estre.
The study of the current porch by analysis of the interior and exterior scree has enabled accurate dating of the phases of its gradual collapse until the cavity was sealed between 29,000 and 21,000 years BP. Since that date no human was able to enter the cave until it was discovered in 1994 following the discovery of the current entrance by speleologists. The Palaeolithic people, whether Aurignacian or Gravettian, entered by this porch, which has since collapsed, transporting quantities of wood which are very significant in terms of the function of the site and which confirm the location of the sanctuary at great depth.