On the other hand, sailors can know, many years in advance, when the tide will turn. That is the ultimate beauty of predicting the movements of the moon.
They can do that now, yes.
But we're talking about the time before writing, before numbers, before mathematics of any kind. What we're talking about is people making notches on sticks.
You've got the timeframe way wrong.
A little blood running down ones leg
I don't believe that most women would agree that their flow constitutes "a little blood." Apparently you've got all your ideas about menstrual flow from tampon ads. Hint - it's not a clear blue liquid.
Predators know that there is blood in us. They don't have to actually smell it in order to find us attractive.
If you can't offer a substantial rebuttal, please offer none at all.
Do you know of such a culture which independantly created a calendar of their own?
The Azteks kept some pretty accurate calendars. Do you believe they did so for the benefit of non-existent Aztek sailors?
This cycle is not something upon which one can base an accurate calendar
Are we arguing about two differnent things? It appears so. You're hung up on the development of accurate, predictive calendars. I'm talking about the invention of keeping track of time.
All one really need do is count the days.
Yes, DB.
That's the point. Menstruation was the stimulation for humans to begin counting days. Hence, the invention of calendars.