A global test of the cold-climate hypothesis for the evolution of viviparity of squamate reptiles

摘要

Aim: The evolution of viviparity in squamate reptiles has attracted considerable scientific attention since the beginning of last century. The cold-climate hypothesis posits that cold regions favor viviparity (and therefore the incidence of viviparous squamates is increased in these regions) because viviparous females can use thermoregulatory behavior to shorten embryonic developmental time and to reduce exposure of embryos to stressful temperatures. However, a rigorous global-scale test of the impact of viviparity on the developmental time and viability of embryos is still absent. Recently developed biophysical models and climate databases enable us to conduct a mechanistic test of this hypothesis.