Despite knowing for decades that some birds and frogs eat prey containing the same potent neurotoxins (Batrachotoxin – BTX), there is a major gap in our understanding of how these convergent adaptations have evolved. Even more remarkably, these animals store the toxins and become toxic themselves, but the source of the toxin and the mechanisms that allow this are essentially unknown. C ombining field and manipulation experiments with comparative genomics, transcriptomics and chemical analyses, I will lead an international consortium of evolutionary biologists, ecologist and chemists to address these major gaps in our understanding of convergent evolution of toxic lifestyles in two distinct vertebrate clades. Specifically, we will: i) determine the source of BTX and its adaptive significance in toxic birds, ii) pinpoint the underlying genomic adaptations allowing for storage and transportation of toxins in both birds and frogs, and iii) evaluate the roles that gut microbial symbionts play in toxin uptake, and in facilitating the hosts’ adaptations to be toxic.