Excavations carried out in 1970 in the Lebombo mountains of Southern Africa, uncovered the fossilised leg bone of a baboon, estimated to be 37,000 years old, that had 29 scratches carved into it. In 1937 the fossilised bone of a wolf was found in Czechoslovakia, that had 37 scratches on its length, grouped in fives. This bone was estimated to be 30,000 years old. Ancient peoples realised that it was useful to group the marks into equal...