The only turtle present on the island, the western painted turtle, is quite common in lakes and ponds and can often be seen basking on logs during sunny days. Painted turtles spend the winter hibernating in mud underwater and may occasionally be active under the ice.
Only two species of snake occupy the island, the northern red-bellied snake and common garter snake. Although common garter snakes are indeed common and regularly observed, the small, copper-brown colored northern red-bellied snakes are easily overlooked. Common garter snakes at Isle Royal often have strikingly different color variations within the population. Colors range from the typical black with creamy stripes, to light or very strong red-orange spots or stripes, to black with deep blue stripes that often make a snake look completely black. Researchers in the park have determined that up to 40% of the garter snake population exhibits extreme color variation. Surprisingly, this color variation is very stable and was noted in similar proportions as far back as 1928.