The function of red and banded patterns in snakes: a review of hypotheses and evidence.

This article critically examines the widely held hypothesis that the bright red and black banded (RBB) coloration of coral snakes (genus *Micrurus* and *Micruroides*) functions as an aposematic (warning) signal and that many similarly colored snakes in the Americas are Batesian mimics of coral snakes. The review finds that theoretical models and empirical evidence supporting aposematism and mimicry in coral snakes are weak or inconsistent, citing issues such as the rarity of coral snakes, the overabundance and polymorphism of mimics, imperfect geographic overlap between models and mimics, and the lack of clear selective predators capable of learning or innate avoidance. Furthermore, similar RBB and complex banded patterns have evolved independently multiple times worldwide, including in Asia, Africa, and Oceania, often in species unlikely to be coral snake mimics, suggesting a broader, yet unidentified, selective force favoring these colorations. The article concludes that aposematism and mimicry fail to fully explain the evolution and maintenance of these patterns and calls for new hypotheses to account for the widespread and recurrent selection of red and black banded patterns and complex banding in snakes globally.