 Archeological studies of Gobustan Rock Art have identified what may be dolphins and porpoises, or a certain species of beaked whales and what may be a whaling scene indicates large baleen whales likely being present in Caspian Sea at least until when the Caspian Sea ceased being a part of the ocean system or until the Quaternary or much more recent periods such as until the last glacial period or antiquity.Although the rock art on Kichikdash Mountain is assumed to be of a dolphin or of a beaked whale, it might instead represent the famous beluga sturgeon due to its size (430 cm in length), but fossil records suggest certain ancestors of modern dolphins and whales, such as "Macrokentriodon morani" (bottlenose dolphins) and "Balaenoptera sibbaldina" (blue whales) were presumably larger than their present descendants.From the same artworks, auks, like Brunnich's Guillemot could also have been in the sea as well, and these petroglyphs suggest marine inflow between the current Caspian Sea and the Arctic Ocean or North Sea, or the Black Sea.