Partly human hybrids appear in petroglyphs or cave paintings from the Upper Paleolithic, in shamanistic or totemistic contexts. Ethnologist Ivar Lissner theorized that cave paintings of beings combining human and animal features were not physical representations of mythical hybrids, but were instead attempts to depict shamans in the process of acquiring the mental and spiritual attributes of various beasts or power animals. Religious historian Mircea Eliade has observed that beliefs regarding animal identity and transformation into animals are widespread. The iconography of the Vinca culture of Neolithic Europe in particular is noted for its frequent depiction of an owl-beaked bird goddess .