Freeze Tolerance and Supercooling Ability in the Italian Wall Lizard, Podarcis sicula, Introduced to Long Island, New York

Italian wall lizards (Podarcis sicula campestris) were introduced to Long Island, New York, in 1967 and have subsequently spread through many urban and suburban communities. Their ability to spread further may be limited by their ability to tolerate the relatively cold winters of New York. We found that these lizards were able to survive cold temperatures by supercooling if they were kept dry. However, if freezing was initiated as would be expected under shallow hibernation conditions, these lizards froze and died rapidly. We speculate that Podarcis sicula must hibernate below soil freezing depth, estimated at greater than 24 cm deep, to survive.