there is another theory, that sound waves were inadvertently enregistered in the brushstrokes/fingerstrokes of painters, so maybe somebody can take high-resolution 3d laser scans of the lascaux cave paintings, then in reconstruction/playback we might be able to hear for the first time in eons, the sounds of woolly mammoths or such, rumbling outside the cave where the cowering artist was pictorially describing on the walls just what he was hiding from. other than that remote possibility, we shall just have to wait for some enterprising entreprenurial genetic scientist to extract usable material from a mosquito trapped in amber, to reconstruct a real living dinosaur, and then we can all hear it roaring its head off, and marvel at science once again. just a thought.