You guys aren’t going to believe this, but back in the old days, there was no toilet seat lid on the toilet. In fact, there was no toilet at all.

Just because it doesn’t flush, it doesn’t mean it isn’t a “toilet”!

Now, granted, I’m being pretty liberal with my use of the word toilet. Let’s be honest: it’s basically a metal box with a toilet seat lid on it.

But not so long ago, you didn’t even get that. River trips used to use ammo cans as toilets. What’s an ammo can? Those little white and blue metal boxes in the picture are ammo cans. We still use them on our trips to store and keep things like trash, condiments, and toilet supplies dry.

Back in the day, though, people sat directly on the ammo cans. The hard metal edges left grooves in their backsides, and so, as the story goes, the term groover was born.

You might hear the groover called a few other things on your river trip, too. I’ve heard it called “the unit” or “Oscar.” I suspect “the unit” is simply guide shorthand, but Oscar is a little more mysterious.

I’ve heard a few different stories about where the name Oscar came from. I’ll leave it to the guides on your Grand Canyon Whitewater trip to share their favorite version, but I’ll offer my own theory: maybe Oscar is an acronym for Outstandingly Superior Constipation Alleviation Receptacle.

At any rate, if you’re not already impressed by our modern, comfortable, high-class bathroom setup, check out Going to the Bathroom on the River for more on what to expect.