I never saw the movie but I had read the book and thought there were other animals in the lifeboat. I just looked up a summary of the book and here’s what it says about the other animals. Again don’t know what they did in the film:
“At the beginning of Part Two, the ship is beginning to sink. Pi clings to a lifeboat and encourages a tiger, Richard Parker, to join him. Then, realizing his mistake in bringing a wild animal aboard, Pi leaps into the ocean. The narrative jumps back in time as Pi describes the explosive noise and chaos of the sinking: crewmembers throw him into a lifeboat, where he soon finds himself alone with a zebra, an orangutan, and a hyena, all seemingly in shock. His family is gone. The storm subsides and Pi contemplates his difficult situation. The hyena kills the zebra and the orangutan, and then—to Pi’s intense surprise—Richard Parker reveals himself: the tiger has been in the bottom of the lifeboat all along. Soon the tiger kills the hyena, and Pi and Richard Parker are alone together at sea. Pi subsists on canned water and filtered seawater, emergency rations, and freshly caught sea life. He also provides for the tiger, whom he masters and trains.”