Triple Jaw Leech

Macrobdella decora, commonly known as the North American Medicinal Leech, is found throughout the northern half of North America. It possesses 3 jaws (seen here), with 50 - 60 denticles (or teeth) on each jaw. When the leech bites, the jaws are moved in a sawing motion to open the wound. Anticoagulants in the leech's saliva keep the blood fluid while the leech feeds, but also for the many months of digestion that follow. The anticoagulants are most noticeable to humans in that leech bites bleed for hours after the leech has been removed.