Wall images are perfectly compatible with the perceptions people could have during their visions, whether one considers their themes, their techniques and their details. The animals, individualised by means of precise details, seem to float on the walls ; they are disconnected from reality, without any ground line, often without respect of the laws of gravity, in the absence of any framework or surroundings. Elementary geometric signs are always present and recall those seen in the various stages of trance. As to composite creatures and monsters (i.e. animals with corporal attributes pertaining to various species), we know that they belong to the world of shamanic visions. This does not mean that they would have made their paintings and engravings under a state of trance. The visions could be drawn (much) later.
Trying to get into touch with the spirits believed to live inside the caves, on the other side of theveil that the walls constituted between their reality and ours, is a Paleolithic attitude of mind which has left numerous testimonies, particularly the very frequent use of natural reliefs. When one’s mind is full of animal images, a hollow in the rock underlined by a shadow cast by one’s torch or grease lamp will evoke a horse’s back line or the hump of a bison. How then couldn’t one believe that the spirit-animals found in the visions of trance - and that one had expected to find in the other-world which the underground undoubtedly is - are not there on the wall, half emerging through the rock thanks to the magic of the moving light and ready to vanish into it again. In a few lines, they would be made wholly real and their power would then become accessible.
Cracks and hollows, as well as the ends oropenings of galleries, must have played a slightly different yet comparable part. They were not the animals themselves but the places whence they came. Those natural features provided a sort of opening into the depths of the rock where the spirits were believed to dwell. This would explain why we find so many examples of animals drawn in function of those natural features (Le Roseau Clastres, Le Travers de Janoye, Chauvet (fig. 14), Le Grand Plafond at Rouffignac).