Have you ever seen the movie Titanic? In the movie, the boat hits an iceberg, crashes, and few people survive. Boring, right? Well, in the book Life of Pi, a boat does crash, and many people are presumably dead, but the main character, Pi, survives because he is thrown into a life boat. Also, another life boat is also set adrift near him, and he hopes its another survivor.
However, when he lifts the tarp, he is startled to find a Bengal tiger, a hyena, a zebra, and an orangutan. He covers the hole back up and gets back to his life boat. He takes a rope, and ties it to the front of the life boats, so that they are always together.
So, because he was thrown onto a lifeboat, he survives, and eventually lands in Mexico, where the only surviving animal, the tiger, goes running into the jungle. Pi starts a new life, and lives on.