The movie opens with Mr. Crane teaching young Crane how to whistle with his whistle whistle (sometimes referred to as the whistler whistle), much like Mr. Crane taught Leo how to whistle when they were younger. Leo hears Mr. Crane whistling when Leo accidentally knocks Mr. Crane over with his hammock while climbing over his hammock on his hammock harness. Leo realizes Mr. Crane whistling because Mr. Crane whistled while Leo knocked him over and learns how to whistle while whistling (instead of