So, have you asked Larry Moran's opinion on this study yet? ;)

Humans clearly do not do this, and I don't think it's an exaggeration to claim this was a biological prerequisite (or as close as you can get to one) for today's mixed-gender offices and the large-scale incorporation of women into the workforce.

Never say never - why couldn't a bonobo-like strategy work? Instead of cigarette breaks, there'd be nookie breaks.

Eighteen dancers is a very small sample size, and dancers are, from my experience, wrecks in their personal lives. Cocaine abuse is nearly 100%. I question whether they accurately recorded being on the pill, the amount of received tips, and the days of their cycle. Also, if one of you statisticians could review the data, you should see a spike in tips every Friday (payday) EXCEPT for a Friday that falls very near the first of the month (when rent is due). If you don't see that spike, the data is suspect.