Having fascinated biologists for centuries, animal colouration is involved in many aspects of animal ecology—including regulating temperature, attracting mates, hiding from and warning predators—and is considered an adaptive trait under strong selective pressure.
This study explores the macroevolutionary variation and drivers of dorsal pigmentation in Eurasian vipers (subfamily Viperinae), exhibiting characteristic zigzag patterns in all species.
By measuring two colouration traits in 39 species, the authors quantified the dorsal pigmentation and performed phylogenetic tests to ascertain associations with ecogeographic variables derived from GBIF-mediated occurrences of each species.
Analyses revealed that dorsal pigmentation correlated positively with maximum precipitation and latitude, and negatively with minimum solar radiation and elevation.
Combined, these results highlight the colouration patterns of vipers as adaptive traits matching parameters of cold environments, irrespective of phylogeny, supporting the so-called thermal melanism hypothesis.