We analyze the archaeological evidence of the deliberate placement of valuables («caches») in mammoth skulls at sites of the Eastern Gravettian Kostenki-Avdeyevo culture (Zaraysk A, E, F, and Kostenki 1 layer I). Six such finds are examined, specifically their spatial arrangement, stratigraphic context, and composition. Special attention is paid to the connection of «caches» with living structures (semi-subterranean dwellings) and ritual complexes, as evidenced by the presence of ocher, specific placement of artifacts, etc. A classification of «caches» is suggested: lost (accidentally left), returnable (intended for subsequent retrieval), and irretrievable (ritual sacrifices). The composition of such complexes is diverse. A «special» cache at Zaraysk E contained 24 artifacts including Kostenki knives, placed in the alveolus of a mammoth skull; at Kostenki 1, a spatula made of a rib with a figured top had been hidden in the skull. Notably, the tradition of using mammoth skulls for storing valuables has been traced over a long period of time at sites of the Upper Paleolithic Kostenki-Avdeyevo archaeological culture belonging to the Eastern Gravettian. It was practiced on the Russian Plain even after the LGM at sites of the Anosovo-Mezin type, representing another cultural tradition. Our findings indicate a complex interaction of utilitarian and symbolic practices among ancient hunters, expanding our knowledge of their worldview.