an american giant millipede (a Narceus species in the americanus/annularis complex) traversing a lichen-covered boulder on a mountaintop (Massachusetts, 8/7/23)
Sometimes referred to as “iron worms”, these large millipedes are often locally abundant in mature forests and mountainous areas in the northeastern US. They spend most of their time hidden in decayed logs and leaf litter but regularly emerge to wander in the open, climbing rocks and trees to graze on lichen. Protected by toxins that deter most predators, they do so even in broad daylight, especially during wet or cloudy weather.