The first studies of the parietal evidences were made at the beginning of the century by H. Alcalde del Rio and L. Sierra, whose results were published in 1911 in the work "Les Cavernes de la Region Cantabrique". In this research 140 figures of animals were analized, besides more than 50 negative hands and other 50 signs. In this first inventory figures of hinds, deers, horses, bisons, goats, aurochs, and some canids, and what they define as an elephant, but it is the figure of a mammoth. Subsequently to this work, since the 50s other briefer works have been published adding some new figures to the initial inventory or interpret some of the published at the beginning of the century, again.

Nowadays and making a critic analysis of the different publications, we can stablish an inventory formed by almost 180 figures of animals, 45 negative hands and about 50 signs. Between the figures of animals, the most represented is the hind, with 56 representations, followed by the horse,bison,deer,goat and aurochs. There are two representations of masks similars to the ones in Altamira or La Garma, and one representation of mammoth in red paint.

The representations of the cave of Castillo have been made during different phases of the Upper Palaeolithic. This way in a first phase at the beginning of the III Style the figures made by blowing and yellow painting can be situated. In a more advanced moment of ancient IV style black paintings can be included.

The more than fifty representations of negative hands and different groups of dots situated in narrower galleries are part of the more characteristic representations of this cave. This type of iconography belongs to early moments of the palaeolithic rock art. The black figures belong to a more advanced moment, in the ancient IV style.