No. 86: Mar-Apr 1993
S. Waller has visited rock art sites in Europe, North America, and Australia. Standing well back from the painted walls, he claps or creates percussion sounds, and records the echos bouncing back. A casual observer might be tempted to call 911. It turns out, though, that rock art seems to be placed intentionally where echos are not only unusually loud but are also related to the pictured subject matter. Where hooved animals are depicted, one easily evokes echos of a running herd. If a person is drawn, the echos of voices seem to emanate from the picture itself!
"At open air sites with paintings, Waller found that echos reverberate on average at a level 8 decibels above the level of the background. At sites without art the average was 3 decibels. In deep caves such as Lascaux and Font-de-Gaume in France, echos in painted chambers produce sound levels of between 23 and 31 decibels. Deep cave walls painted with cats produce sounds from about 1 to 7 decibels. In contrast, surfaces without paint are 'totally flat'."
What did the ancient artists have against cats?
(Dayton, Leigh; "Rock Art Evokes Beastly Echos of the Past," New Scientist, p. 14, November 28, 1992.)