The Ekain bird
This piece, found in the excavation of the entrance to the cave of Ekain (Deba) by the anthropologist Jesus Altuna in 2008 is the outline of a bird made on the ribs of a large bovine animal (auroch or bison), with heavy modelling in the interior. The rib had previously been sunk according to a plane parallel to its surface and then worn away in its interior. It is thought to be 13,860 years old. The bird is depicted from a twisted perspective. The head is seen in profile according to a sagittal plane that divides the animal (into two symmetrical halves). However, the body is seen from below (or above) in accordance with a frontal plane. It is the only way both wings can be seen at the same time. Both the motif that is depicted and the medium and twisted perspective are particularly uncommon characteristics for the period and make the piece exceptional.