Leeches are invertebrates, with slender, segmented, moist bodies, similar to worms. Leeches come in three varieties: land leeches, freshwater leeches, and marine leeches. While the word “leech” usually brings to mind visions of slimy little blood suckers, most leeches do not actually rely on human blood, but rather prey on small insects and other invertebrates. […]