We describe the successful predation of a black-bearded saki monkey (Chiropotes satanas chiropotes) by a Harpy Eagle (Harpia harpyja) in the Brazilian Amazon and briefly recap two past Harpy Eagle-primate predation interactions. The physiological limitations that raptor anatomy places on individuals during predation attempts are considered along with escape behaviors used by primates to exploit these limitations to increase their chances of survival. In particular, we focus on primate flight paths and startle vocalizations.