When unexpected predator-prey interactions are observed, abiotic conditions can reveal insights about the ecology of the species involved. During one of the warmest months of May in the last 30 y (2008), we observed an adult Northwestern Pond Turtle, Actinemys marmorata, preying upon a paedomorphic Coastal Giant Salamander, Dicamptodon tenebrosus, in the South Fork Eel River. Compiled records of temperatures when moribund, bitten, or dead D. tenebrosus were found in the sunny mainstem river highlight their vulnerability when facing thermal stress beyond their usual habitat in cool shaded tributaries.