Leeches

Leeches have very muscular bodies and avidly swim side ways through the water when disturbed. At each end of the body are single suckers. The head is at the narrower end of the body and has a set of eyes, important for identification of the different species. The Medicinal Leech, one of the few European leeches to consume human blood, is now quite rare and a protected species. However, as a group they are very common and widespread across all of Europe. They live in freshwater, ponds and rivers.

ECOLOGY: Leeches are capable of quite rapid movement. Large species like the Medicinal Leech can detect movement in the water and swim rapidly (sometimes in large numbers) towards the vibration. They swim with an undulating action. Once attached to the host by the suckers the proboscis comes forward with teeth and begins to feed. This may be just to break the surface and drink blood or in other types to feed on insects with their tough jaws. Those that feed on blood use an anti-coagulant to stop the blood clotting. As they feed the body may double in size and when finished they just drop off on to the ground. They can live happily out of water for sometime. To move they "loop" along the ground. Once fed they can stay under a stone or other protected area for up to a year before they need another feed. They usually lay eggs in cocoons attached to stones under water. Many leeches in Europe are feeders on invertebrates such as molluscs and insects.
The Medicine Leech was used for many years for "blood-letting" and for the treatment of infected wounds. Any pus would be removed by the leech. In recent years research has looked at the uses of the leech in medicine once more.