Ancestral state reconstruction of diel activity pattern. Bayesian SIMMAP ancestral state reconstruction using the constrained tree for the history of the ‘Diel Activity Pattern’ character. Nocturnality is inferred to be ancestral for snakes. The grey box marks the clade Colubroidea, within which diurnal habits re-evolved. Note that SIMMAP estimates the most likely states for tip taxa that are coded as missing or polymorphic – as such, some of the tip states exhibited in this figure are inferred tip states, not coded tip states (e.g., the fossil taxa were coded as missing data; the states they exhibit here are states inferred by the SIMMAP method). Fossil taxa are marked with a dagger (†).