Red wiglers are a misspelling of red wigglers, a kind of earthworm that lives in decaying matter instead of soil. They have numerous other common names, including tiger worms, but they are known to science as Eisenia fetida.
Red wigglers consume manure, dung, decaying vegetation and other organic material that has been left to rot. As such, they are commonly used for composting. Their species name, fetida, is derived from the Latin word for "foul smelling." This does not refer to their rotting habitats but rather to the foul-smelling liquid they emit to defend themselves from predation. Another defense they employ is thrashing, which is why they are called wigglers.