meeting Hilda Spielvogel and then working

there.

And what I found in Peru was also true in Bolivia.

It wasn't something unique about Minyoa.

you know, that they were working hard and having all these babies.

And so because I'm interested in mechanism though, how was it possible? What were the hormones like? What was the birth length? What were they doing that made it possible to have so many babies under these very arduous conditions? And there was an idea out there that basically when you work hard, like exercise of menorrhea, then you should have lower progesterone and you're not going to be able to make as many babies.

Is that true? So you might expect seasonality in birth, for example.

And I'm wondering if you could talk about how ovulation is optional and what it means for our demographic understanding of fertility patterns, as well as our understanding of human evolution.