Londoner solves 20,000-year Ice Age drawings mystery- PublishedA London furniture conservator has been credited with a crucial discovery that has helped understand why Ice Age hunter-gatherers drew cave paintings.In particular, he examined a 'Y' sign on some paintings, which he felt might be a symbol for "giving birth" because it showed one line growing out from another.He collaborated with a team including two professors from Durham University and one from University College London and, by working out the birth cycles of similar present-day animals, they deduced that the number of marks on the cave paintings was a record, by lunar month, of the animals' mating seasons.Prof Paul Pettitt, of Durham University, said he was "glad he took it seriously" when Mr Bacon contacted him.He added: "In turn, we're able to show that these people, who left a legacy of spectacular art in the caves of Lascaux [in France] and Altamira [in Spain], also left a record of early timekeeping that would eventually become commonplace among our species.""