Leeches: Hirudinea

Physical characteristics: Possibly the largest freshwater leech, the giant Amazonian leech can grow up to 17.72 inches (450 millimeters) long and 3.93 inches (100 millimeters) wide. Adults are dark gray-brown. Younger individuals have a broken stripe down their backs and patches of color on every third body segment. They have only one pair of eyes.

Geographic range: They live from the mouth of the Amazon River, north to Venezuela and the Guianas.

Habitat: The giant Amazonian leech lives in coastal wetland marshes.

Possibly the largest freshwater leech, the giant Amazonian leech can grow up to 17.72 inches (450 millimeters) long and 3.93 inches (100 millimeters) wide. (Illustration by Bruce Worden. Reproduced by permission.)

Diet: Young leeches feed on amphibians. Adults usually attack caimans, anacondas, capybaras, and domestic cattle.

Behavior and reproduction: This species is a good swimmer and is usually found under rocks or in debris in the water while they digest their meals and carry their cocoons.

Sperm packets are attached to the body of the mate. Eggs are kept in a sac underneath the parent's body until they hatch and are carried to their first blood meal by the parent.

Giant Amazonian leeches and people: A special chemical isolated from the saliva of the giant Amazonian leech is sometimes used as a medical treatment to break down blood clots in humans.

Conservation status: The giant Amazonian leech is not considered endangered or threatened. ∎