Do conspicuous tails and dietary shifts indicate luring behavior in vipers (Serpentes Viperidae)?

Aggressive mimicry is an ambush strategy observed in various animal taxa, including snakes, which use caudal luring (CL) to attract prey. CL involves cryptically colored snakes waving a conspicuous tail tip (CTT) to mimic worm-like invertebrates, luring prey that feeds on such organisms. This strategy is common among Viperidae, particularly in juveniles, which often exhibit ontogenetic shifts in diet (OSD) from ectothermic to endothermic prey. Although CL, CTT and OSD are assumed to be correlated, this relationship has never been empirically tested. This study investigated the origin and persistence of CL, CTT and OSD in Viperidae evolution, assessing their phylogenetic signal and testing for correlations. Data on the presence or absence of these traits were compiled from the literature, and phylogenetic comparative methods were used to measure phylogenetic signal, test correlations and reconstruct ancestral character states using parsimony and maximum likelihood. Results revealed strong phylogenetic signals for all three traits and significant correlations between each pair. Maximum likelihood reconstructions suggested that the ancestral Viperidae possessed CL, CTT, and OSD, while parsimony analyses indicated CL and CTT were present in the ancestor, but OSD was not. These findings support the hypothesis that CL, CTT and OSD are evolutionarily linked and have been integral to Viperidae since their origin. Despite being the most comprehensive study on these traits, significant gaps in viper natural history data were identified. This highlights the need for further descriptive ecological studies to enhance understanding of viperid biology and support broader macroevolutionary research.