A green sea turtle (Chelonia mydas) encountered around Hilton Head Island represents one of the world’s largest hard‑shelled marine reptiles, known for their herbivorous diet and reliance on warm, shallow coastal habitats. Although loggerheads dominate South Carolina nesting activity, juvenile green turtles forage in the region’s estuaries, where seagrass and algae provide essential nutrition. Like all reptiles, green turtles are ectothermic, meaning their body temperature depends on the surrounding water. When sudden winter cold fronts push water temperatures below roughly 50°F (10°C), turtles can experience cold‑stunning, a hypothermic state in which they become lethargic, lose the ability to swim, and may float to the surface or wash ashore. Cold‑stunned turtles are vulnerable to drowning, boat strikes, and predation, and require rapid rescue to prevent secondary complications such as pneumonia or shock. Conservation groups along the Southeast coast monitor for these events, as even a single cold snap can impact multiple species—including green turtles—within the island’s interconnected marshes and tidal creeks. Understanding cold‑stunning helps highlight how sensitive sea turtles are to temperature shifts and why protecting their habitats is essential for long‑term survival.