Anyone who has ever been in a a car with a woman for more than five miles knows one immutable fact: they have to pee already. They went while getting ready to leave. Right as you held the door open for them, they ran back in to pee once more. Now that you have been driving for ten minutes, they need to pull over and pee again. No doubt, the first thing they will do on arrival is pee again.
This leads me to one inescapable conclusion. Cows, deer and other ruminants have four-chambered stomachs. Women, have four-chambered bladders.