Stone Age fantasy in a Mayan-style jungle

Tarek is the only one in all the tribes of the Lost that can't hear the Song, the gentle green magic that helps them survive the deep wilds of the jungle. What he has instead is the dreaded, fabled blood magic, the curse of the ancients. If anyone discovers his dark thirst, he will hang. A rival in the tribe is trying to keep him from marrying his betrothed Yaretzi, and a wandering elder named Xochil knows more about Tarek than is good for him. The yearly flood approaches, and either Tarek stays home and risks death or goes wandering in search of a cure to his curse... and the deep jungle holds a thousand deaths for those foolish enough to wander.