Skin toxicity evolved alongside bright coloration, perhaps preceding it. Toxicity may have relied on a shift in diet to alkaloid-rich arthropods, which likely occurred at least four times among the dendrobatids. Conspicuous coloration in these frogs is further associated with diet specialization, body mass, aerobic capacity, and chemical defense. Either aposematism and aerobic capacity preceded greater resource gathering, making it easier for frogs to go out and gather the ants and mites required for diet specialization, contrary to classical aposematic theory, which assumes that toxicity from diet arises before signaling. Alternatively, diet specialization preceded higher aerobic capacity, and aposematism evolved to allow dendrobatids to gather resources without predation.