18-Inch Leech Attached to Your Arm?

Common Name: Giant Amazon Leech

Scientific Name: Haementeria ghilianii

Status: Unsure, not yet assessed by IUCN Redlist

The giant amazon leech is the largest known freshwater species of leech. It grows up to almost 18 inches long and is about four inches wide! Imagine having one of these latch onto your arm…

This large leech is a species that feeds on blood from mammals, reptiles, and amphibians. Unlike the medicinal leech we’re familiar with, the giant amazonian leech is jawless and uses a proboscis to suck blood from its prey (medicinal leeches have jaws and teeth).

A diet of blood is actually quite a difficult diet to have. Blood is very nutritious, but it lacks certain amino acids and nutrients that living things need. In order to overcome this, the giant amazon leech has a symbiotic relationship with bacteria that are allowed to grow inside a special organ in its digestive system. These bacteria actually create the amino acids and nutrients for the leech!

sources: Smithsonian, PBS, invertebrates class