Embryonic Development in Two High‐Elevation Oviparous Lizard Species: Contrasting Strategies for Coping With Cold Climates

ABSTRACT Understanding how species respond to local climates is crucial for predicting their responses to climate change. The cold climate of high elevations constitutes a physiological challenge for reptiles, especially during the embryonic stages of oviparous species, because embryos have limited ability to thermoregulate behaviorally. To examine how high‐elevation lizards maximize hatching success under cold climates, we compared reproductive traits and the temperature dependence of embryonic development in two lizard species occupying contrasting mountain microhabitats: the forest‐dwelling Sphenomorphus taiwanensis and the grassland‐dwelling Takydromus hsuehshanensis . We quantified embryonic stage at oviposition, measured post‐oviposition embryonic developmental duration across a range of constant temperatures (15°C–34°C), and recorded shallow‐soil temperatures in forests and open sites in their habitats. We found that T. hsuehshanensis laid early‐stage embryos that appeared to require warm nesting sites to complete development, whereas S. taiwanensis laid advanced‐stage embryos capable of completing development in the cool forest environment. These results suggest that these species use two distinct strategies: T. hsuehshanensis primarily uses a behavioral strategy (maternal nest‐site selection), whereas S. taiwanensis primarily uses a physiological strategy (maternal egg retention). These strategies appear to be closely associated with their habitats' thermal characteristics (cold forest vs. warm grassland). By linking microhabitat thermal regimes to reproductive strategies—maternal egg retention versus nest‐site selection—our findings provide a basis for anticipating species‐specific responses to shifting mountain temperature regimes.