Nephelopsis obscura, the common ribbon leech, is black and slimy, segmented, and like the earthworm, hermaphroditic. In the shallow waters of the Great Lakes region, it spends the day buried in mud and then, when darkness falls, emerges to feed on animal remains. Bobby Matthews is an Ojibwe who traps these leeches on the aptly named Leech Lake Indian Reservation in Minnesota. “As soon as the ice goes out in April I start looking around,” he says. At dusk, he sets his traps—perforated containers suspended from a Styrofoam float—and removes them at dawn. A sturdy overnight haul, sold to convenience stores and bait shops, can net him $1,000. Though Matthews makes a decent living as a leech trapper, he is also a man of countless other seasonal trades: a collector…
