Leeches: Hirudinea

Leeches are all carnivores (KAR-nih-vorz) and feed on the flesh or fluids of other animals. Some species feed only on the blood of their prey. Many leeches are predators that ambush a wide variety of invertebrates (in-VER-teh-brehts), animals without backbones. Prey includes insects, earthworms and their relatives, beach hoppers, snails, and freshwater clams. Predatory leeches swallow their prey whole or pierce the bodies of their victims with their retractable, needlelike mouthparts, or proboscis (pruh-BAH-suhs). These mouthparts are then used like a soda straw to suck out bodily fluids.

Blood-feeding leeches attack fishes, turtles, crocodiles and their relatives, frogs, ducks, geese, other water birds, and mammals, including humans. Some leeches feed on only one kind of animal. Others will feed on anything. If larger prey is not available, these leeches will survive on worms, insects, and other invertebrates. Although some blood-sucking species use a proboscis, most use their jaws to pierce the skin of their victims. They have two or three razor-sharp jaws, each shaped like half of a circular saw blade. Two-jawed leeches leave a V-shaped mark. Those with three jaws leave a Y-shaped wound. These leeches have chemicals in their saliva that prevent the blood of mammals from clotting, either at the wound or inside their own bodies.