Copperhead

Copperhead spotted along a hiking trail near dusk, in the Wichita Mountains Wildlife Refuge, Oklahoma. As I was returning from a long hike in "the Narrows" with my son, I failed to see this guy and nearly stepped on it (I was surprised at the time that the snake did not react to my foot's near miss, and only sat very still... but have since read that this is a common defense mechanism for the copperhead).