Daniel Blumstein

So it also turns out if you're a mammal, you start off feminized and have to be defeminized.

And you get defeminized by having little bursts of testosterone when you're in utero.

that begin sexual differentiation.

So he found that natural variation in the location you were in that peapod influenced what you were exposed to.

Your siblings around you, the testosterone leaked through and females became more masculinized.

The distance between their vagina and their anus increased.

I mean, you can try this at home and measure people if you want, but you know.

So we didn't know.

We were not doing cesareans on these marmots.

We studied them in the wild.

But a former postdoc, Raquel Monclas, said, well, you're measuring it in general.

She's like, oh, yes.

She's like, I want to sort of start analyzing this data set.

I'm like, yes.

And what we discovered is that we could look at emergence sex ratio.

So we don't know.

Marmots are born.

They probably live about

28 days in the burrow and are nursing.

And then they emerge after about 28, 30 days.