The crab replied, "Okay, let's trade."
They traded. The crab took the persimmon seed back and planted it in the field in front of his home. The monkey gobbled down the riceball right there.
Sometime later a sprout emerged from the persimmon seed, which turned into a tree, and eventually bore flowers which turned into fruit. However, the crab wasn't able to pick the persimmon fruit. Therefore, the crab went to the monkey's place and made a request.
"Saru-san, Saru-san. Won't you pick the persimmon fruit for me?"
"Okay, I'll do it."
The monkey agreed very happily, and started off. But when he climbed the tree, he gobbled down the ripe fruit by himself.
"Saru-san, Saru-san. Won't you give me one too?" the crab asked from the foot of the tree. The monkey took a hard, green persimmon and threw it straight at the crab. The crab was angry, and cursed the monkey bitterly as he escaped to his hole. Now the monkey got angry; he climbed down from the tree and chased after the crab. When the crab escaped into his hole, the monkey thrust his own tail into the hole and swished it around as he yelled, "Hey, crab! Come on, crab!"
Then the crab reached up with his pincer and clamped on to the monkey's tail. The monkey yelled out in pain, and asked the crab to pardon him.
"Kani-don, Kani-don! Please let me go. If you do, I'll give you three hairs from my tail."
And that, they say, is why there are hairs growing from the end of the crab's pincer.