The scene: We are watching some show and beavers are on...PBS versions of beavers that is.
The boy: It's a dam!
Me: That's right. Who made that dam?
The boy: Beavers make them.
Me: Why would they do that?
The boy: They make them to stop the water from getting from this side to that side.
Me: But how do they build them?
The boy: They use their teeth and they eat through a branch and then they pile those up and it blocks the water.
Me: oh, ok