Handle with care: the thermal consequences of short-term handling in mole salamanders

Accurately measuring body temperature is critical for understanding how ectotherms interact with their thermal environment. In amphibians, traditional methods like cloacal thermometry require restraint, potentially altering body temperature through stress and heat transfer from human hands. Here, we used infrared thermography to examine how short-term gentle handling (2 min) impacted skin temperatures ( T skin ) in two species of mole salamanders ( Ambystoma laterale and A . maculatum ) by combining field and lab experiments. In the field, we randomly assigned salamanders to a handled or control group, whereas in the lab salamanders were assigned to a heating plate set to hand temperature or a control group. We also scored salamander activity (active vs. inactive) in both settings. In the field, handling increased T skin in both species, with the head warming up more than the dorsum. Moreover, A . laterale experienced an overall greater magnitude of thermal change (Δ T skin ) than A . maculatum due to body size differences. In the lab, contact with the heating plate increased T skin , with head T skin being consistently warmer than dorsal T skin . We also found that Δ T skin was greater for the handled than the heating plate group (Δ T skin = 4.86 ± 1.21°C vs. 1.72 ± 0.70°C, respectively), suggesting that handling may amplify heat gain. Warmer salamanders were more prone to be active regardless of whether they were handled or in contact with a heating plate. Our results demonstrate that short-term handling can cause rapid warming that exceeds rates used in heat stress studies, with implications for data reliability and amphibian welfare in thermal biology assays. • Short-term handling rapidly increased skin temperature in mole salamanders • Field-handled salamanders warmed up more than lab-heated individuals • Head temperatures warmed up more than dorsal temperatures in both field and lab • Ambystoma laterale experienced overall greater temperature increases than A. maculatum • Handling-induced thermal artifacts must be considered in the design of thermal biology studies