The Michigan DNR page on the Eastern Hog-nosed Snake (Heterodon platirhinos) says this is a:
A thick-bodied, slow-moving snake with a flattened, upturned “nose.” Color is variable some have dark spots and blotches on a yellow, orange, or brown background, but other specimens are solid black, brown, or olive with little or no visible pattern. Easily identified by defensive behavior. Adult length: 20 to 40 inches.
A snake of open, sandy woodlands – found in the wooded dunes of western Michigan. The upturned snout is used to burrow after toads, a favorite food. When threatened, hognose snakes puff up with air, flatten their necks and bodies, and hiss loudly. (This has led to local names like “puff adder” or “hissing viper.”) If this act is unsuccessful, they will writhe about, excrete a foul smelling musk, and then turn over with mouth agape and lie still, as though dead. Despite this intimidating behavior, Hog-nosed snakes are harmless to humans.
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