The Beasts themselves are the most prominent motif in the narrative, appearing again and again before their true nature becomes clear. Because so little is known about them, they become something of a blank canvas on which the members of the expedition project their fears and hopes about the journey. The open question of their identity and intentions—whether they are human or animal, good or evil, mystical or mundane—symbolizes the broader sense of uncertainty and blurred boundaries that pervades every phase of the expedition. 

When Alex and Nadia do discover the city of the Beasts and learn the details of their symbiotic relationship with the People of the Mist, the Beasts shift from being an emblem of uncertainty to one of stability. With their long lifespans and prodigious memories, the Beasts possess a true sense of eternity that is beyond the grasp of any of the human characters. Their connection to the tribe is similarly immovable, as the two groups of beings have sustained each other consistently for innumerable years. This shift in the symbolic meaning of the Beasts mirrors the personal and spiritual changes that Alex and Nadia undergo, as they move from childish uncertainty toward embracing their stable, eternal natures as Jaguar and Eagle.