Department of Environmental Conservation

D E C banner

Leeches (Hirudinea)

General Information about Leeches (Hirudinea)
Life history Leeches mate in the spring. Some types of leeches put their eggs in a cocoon and deposit them; others carry their eggs on their body. Most leeches are dormant, buried in the sediment, during the winter.
Diversity There are about 8 different families in North America.
Flat bodied with suckers at both ends of the body; the body is divided into 34 segments.
Habitat & Feeding Freshwater leeches live in lakes, ponds, springs, streams, or marshes. They can be sanguivorous (eat blood), predators, or parasites.
Water quality indicator status Some kinds of freshwater leeches can tolerate pollution, however they are rarely found in fine sediments because they cannot attach their bodies to the surface. An abundance of leeches at a stream site may indicate some kind of pollution stress.
Fun facts
  • Some leeches can live for up to 15 years.
  • Some of the blood sucking leeches will only feed every 2 years.