From the box:
12 gates are positioned on the board, in arbitrary sequence. Each player is issued 3 animals: one snake, one rhinoceros, and one elephant. Three of the gates are too low for any of the animals to pass under; three other gates can be passed only by the snake; another three gates are high enough to let the snake and the rhinoceros through, and three gates are high enough to allow all the animals to pass.

Players take turns rolling the dice, changing the position of the gates and advancing their animals towards the finish line.