But there were some mysteries.First,when you look at a typical Namibian painting or engraving,you see the tracks are repeated,there are dozens of tracks for the same animal.You'd expect just one clear illustration if the reason - the aim - was to teach tracking.

Now there were two more problems.Why are some of the engravings of animals very accurate as you'd expect - all clearly identifiable - and others quite unrealistic?

And another mystery - some of these unrealistic animals - that's in the engravings - seem to be half human.Some,for example,have got human faces.Many researchers now think that these were pictures the wise men engraved of themselves.They believed they could use magic to control the animals they had drawn,so the hunters could then catch them for food.

This shows you some of the dangers of coming from one culture to another,as we'll be doing,without understanding it fully.Scholars imagined that children looked at rock art pictures to learn to track - just because they themselves had learnt skills from pictures;many researchers now believe that rock art had a much more complex purpose.And we'll talk more about it next week!