This is a popular children’s story in India that offers both a moral lesson and an example of fair division.

Here is a decent (but very cheesy) video that relates the tale. The text of the story is after the jump.

Video: the cats and monkey



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"All will be well if you use your mind for your decisions, and mind only your decisions." Since 2007, I have devoted my life to sharing the joy of game theory and mathematics. MindYourDecisions now has over 1,000 free articles with no ads thanks to community support! Help out and get early access to posts with a pledge on Patreon. .

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Rough transcript of video: the cats and the monkey

Once upon a time, in a village where only animals lived, there lived two cats who were neighbors. They were not very fond of one another and often fought.

One day as the two cats returned home, after a long day of work, they found a piece of cake lying abandoned on the road. It laid between the homes, so it was not clear who it belonged to.

“Yummy, I am going to have a great supper tonight!” exclaimed Tom the cat as he approached the cake. The other cat, Timmy, said, “Watch out, that piece of cake there is mine!” The two cats began yelling loudly and circling the cake, making sure the other cat did not get to it first.

A monkey was passing by and heard the sounds and reached them. “What is the matter? Can I help you?” Tom said, “I found this cake first, and I want to eat it!” Timmy then said, “But it was lying near my house as well, so maybe it was meant for me.” The cats began shouting and fighting once again.

The monkey said, “Stop, why don’t you both share the cake? It’s large enough for both. I can help you cut it into equal halves and give each of you a piece.” The cats thought about it and agreed. This was the best solution.

The shrewd monkey deliberately cut the cake in unequal halves. He offered the smaller piece to Tom, who replied, “Hey, but his piece is bigger!” The monkey said, “That’s okay, I will eat a small piece from it and it shall be the same.” The monkey ate a large chunk out of Timmy’s cake. Now this made Timmy’s piece smaller and Timmy complained, “Now the other piece is bigger.”

The monkey said, “No problem, I will eat a bit from Tom’s and it will be all equal.” Saying so, he ate another large piece of Tom’s cake, making Timmy’s bigger. And thus, the monkey ate away a major part of the cake.

Finally, only one small portion of cake was left. Seeing it, the monkey said, “Oh, it is such a small piece. If you cut it in half, no one will be happy. So let me help you and eat it.” The monkey ate the last piece. “See that was easy, I solved your problem, didn’t I?”

Thus, the clever monkey ate up the entire cake and the foolish cats didn’t even realize they were being tricked. They were so greedy and full of anger for one another.

The moral of the story is when you argue, someone else can win.

The story in the modern day

The cats were exploited because they could not trust each other and were jealous. In fact, they need not have resorted to a third-party solution. There is a game theory solution that in fact capitalizes on the mutual distrust they have. The solution is I cut, you choose: one cat should cut the cake and the other cat gets to pick which piece. This mechanism will lead to an equal and fair division.

One can also think about variants of the story. Here’s how it would go if the monkey was…

…a lawyer: the monkey would arbitrate in the same way by eating the shares of each cat’s cake. At that point he explains he has helped them out so much and takes the remaining piece as his fee.

…an investment banker: the monkey would explain the cake is far too valuable to eat given the miracle of compound interest. Better to give the cake to him as an investment and he’ll return 100 cakes when the cats retire. The cats agree. The monkey runs away with the cake and never returns.

…a tax official: the monkey would explain the newly found cake is subject to taxes and withholds 50 percent of the cake. The monkey then audits the cats for other unreported income. The monkey doesn’t find much, but he takes the rest of the cake as a penalty.

…an accountant: the monkey would explain they should avoid taxes by placing the cake as an asset in an “irrevocable trust.” The cats can never access or eat the cake, but they can pass it on to their heirs tax-free.

…a mathematician: the monkey would explain there exists a solution using cake-cutting algorithms. The task of dividing the cake is trivial, he explains, and is left as an exercise to the cats.