Daniel Blumstein

And maybe they mate with a couple, but that's because the males aren't successfully defending the females.

They don't have a lot of paternal care, but there is maternal care for sure.

In some cases, fathers might stick around and help a little more, but who knows?

However, yellow-bellied marmots, which are these facultatively,

plastic species kind of do everything.

Sometimes in small habitat patches, we have one female with one male and they live a monogamous life.

In some cases, the females there and the males

gallivanting around and visits her and whatever.

In some cases, the male hibernates with the babies and the wife.

In other cases, they don't.

In some cases, the moms die and the kids can make it through alone.

When we look at the female's perspective, often successful big groups are big because females recruit more young to hang out with them.

What does that mean?

They let their daughters stick around.

Their sons pretty much all disperse and some of the females stick around.

So then you have these multi-female matrilines, matrilineal social organization, mother and her offspring.

And in those cases,

We see all sorts of interesting things.

Sometimes we see co-nursing.

Sometimes we have lots of tension.