The most subtle joke

A group of animals sailed out to sea. When they were caught in a storm, they threw away everything, or the hull was too heavy. The monkey suggested telling a joke. If someone doesn't laugh, throw him down. When drawing lots, the monkey really told a joke when he first drew. Everyone laughed, but the pig didn't. Everyone threw the monkey down without saying anything. After a while, the boat was hit by a heavy dog, but the pig still didn't laugh the same joke. Everyone threw the dog away without saying a word. Over and over again, the pig didn't laugh. An honest goat won't laugh if he wins the lottery. It looked at the pig and was scared to death, but it began to laugh before it was said! Everyone wondered why the pig said that I realized that the joke told by the monkey was so funny.