The lizard abides: cold hardiness and winter refuges of Liolaemus pictus argentinus in Patagonia, Argentina.

In environments where the temperature periodically drops below zero, it is remarkable that some lizards can survive. Behaviorally, lizards can find microsites for overwintering where temperatures do not drop as much as air temperature. Physiologically, they can alter their biochemical balance to tolerate freezing or avoid it by supercooling. We evaluated the cold hardiness of a population of Liolaemus pictus argentinus Duméril and Bibron, 1837 in the mountains of Esquel (Patagonia, Argentina) during autumn. Additionally, we assessed the thermal quality (in Degree-days) of potential refuges in a mid-elevation forest (1100 m a.s.l.) and in the high-Andean steppe (1400 m a.s.l.). We analyzed the role of urea, glucose, total proteins and albumin as possible cryoprotectants, comparing a group of lizards gradually exposed to temperatures lower than 0°C with a control group maintained at room temperature. However, we found no evidence to support the presence of freeze tolerance or supercooling mechanisms in this species as related to the analyzed metabolites. Instead, the low frequency of Degree-days below 0°C and temperatures never lower than -3° C in potential refuges suggest that L. pictus argentinus might avoid physiological investments (such as supercooling and freeze tolerance) by behaviorally selecting appropriate refuges to overcome cold environmental temperatures.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author