Hey there, fellow puzzler. Stop me if you’ve heard this one before:
A farmer with a wolf, a goat, and a cabbage must cross a river by boat. The boat can carry only the farmer and a single item. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. The farmer must help them all cross the river without anything being eaten.
This is known as a river crossing puzzle, and there have been many versions over the years. In fact, the earliest known variation, printed in Propositiones ad Acuendos Juvenes (Problems to Sharpen the Young), dates back to the 9th century!
Sometimes the puzzle features missionaries and cannibals crossing a river, and you cannot allow the missionaries to be outnumbered at any point on either shore, lest they be eaten. Sometimes it features jealous husbands crossing a river with their wives, where none of the men will allow his wife to be alone with either of the other men. Sometimes it is knights and squires, and the squires are afraid to stay with the other knights.
I’m going to ignore the racial and misogynistic energy of those examples and focus on the wolf, goat, and cabbage version, which is the one people are most familiar with. (Although the animals do change from riddle to riddle. Sometimes it’s wolves, sheep, and cabbages, other times it’s foxes, chickens, and grain, or foxes, geese, and seeds.)
The traditional answer works for any variation:
- you take the prey (goat, sheep, chicken) across
- you come back with the boat otherwise empty
- you take either the predator (wolf, fox) OR the prey’s food (grain, cabbage, seeds) across
- you come back with the prey in the boat
- if you took the predator first, you bring the prey’s food this time. If you took the prey’s food first, you take the predator this time. Either way, you leave the prey behind on this trip
- you come back with the boat otherwise empty
- you take the prey across
It’s fairly simple as brain teasers go, but the main trick is realizing that you can bring things back with you.
Now, logistically speaking, I have to ask something. Whether it’s a goat or a chicken or a sheep, whether it’s a wolf or a fox, they can all swim, so why not tie a rope to one on one side of the boat, a rope to the other on the other side, and tow them along as you row the grain/seeds/cabbage across?
Yeah, I am one of those all-the-groceries-in-one-trip guys. How did you know?!
The impracticality of this has crossed the minds of others as well. My friend Krud wrote on Twitter:
The folks at XKCD also found a simpler way while asking a very reasonable question:
In an episode of the TV show Fargo, the riddle was posed involving a fox, a rabbit, and a cabbage, and one of the characters immediately gets stuck on the details before offering the following solution:
Pepper: A Turducken.
Budge: A what’s that now?
Pepper: He stuffs the cabbage in the rabbit and the rabbit in the fox, and he eats all of them.
Budge: That’s not the answer.
Pepper: It’s an answer.
Someone online noticed that Martin Freeman’s characters have encountered this riddle twice between The Office and Fargo:
I also found a post online where someone suggested this delightfully impractical solution: “He puts the fox and the seed in the boat and pushes it to the other side. Then he finds the nearest ledge and glides across with the chicken.”
You know what? It’s innovative. I’ll give ’em that.
This riddle has naturally made its way into pop culture. (Apparently it even appears in a Peppa Pig cartoon!)
In The Simpsons episode “Gone Maggie Gone,” Homer must solve the river crossing riddle. Santa’s Little Helper can’t be left with Maggie, or he’ll chew on her favorite stuffed animal. Maggie can’t be left with the jar of poison because it looks like candy.
Naturally, they manage to create their own variation on the riddle and lampoon the original all in one fell swoop:
In an episode of Dropout’s Make Some Noise, they actually reference the river crossing puzzle WHILE making fun of the Riddle of the Two Guards:
And of course, sometimes the wolf-sheep-cabbage problem escalates with the introduction of more factors to be considered.
XKCD shared how complicated the river crossing becomes with a few more unexpected additions:
An episode from the 2010s Powerpuff Girls TV show also dealt with a more elaborate version of the river crossing riddle. In the episode “Splitsville,” Bubbles tries to solve the riddle while dealing with further complications like tourists, a robber baron, and the Raptor King:
At this point the river crossing riddle has essentially become pop culture shorthand for any problem that is getting out of hand through overworked analysis.
Writer Cleolinda Jones referenced the problem while discussing the abject ridiculousness of The Twilight Saga:
Yeah, it’s like, Bella wants to be a vampire but she doesn’t want to be a vampire before she’s had sex as a human, and Edward doesn’t want her to be a vampire but he wants to get married, but Bella doesn’t want to get married unless she can be a vampire, but Edward won’t have sex with her until they get married, and then you put the fox and the grain in the boat and you leave the goose back on the riverbank.
XKCD has similarly used the problem as a punchline to a comic strip about overthinking things:
As you can see, while most of us will never encounter a real-life use for the river crossing puzzle in our lifetimes, at least we’re prepared for the possibility.
Now, if you’ll excuse me, I need to get this beaver, this kite-eating willow tree, and my favorite kite across the street to the park in time for the picnic. See ya!
