Leech

Statistics

Taxonomic subclass: Hirudinea

Length: 0.5 to 6 cm

Average life span: up to 10 years

When To See

They’re active all year but very sluggish in winter.

Photo credit: PondLife

Habitat

Leeches are related to earthworms and have soft, segmented bodies with suckers at each end.  Leeches have a fearsome reputation as bloodsuckers but pose no threat to people visiting their local rivers.  The only species capable of drawing blood in humans is the medicinal leech Hirudo medicinalis which is only found in a few sites across the UK. All leeches are predatory or parasitic (such as the fish leech, Piscicola geometra above) and rely on other living organisms for nourishment. They are not too fussy about the water they live in and can be tolerant of some degree of pollution. The females lay their eggs in bundles on the vegetation submerged below the water’s surface.

How To Identify

Long slender body which moves in a looping manner.  Leeches are surprisingly good swimmers. Can be very dark brown to yellow-brown in colour. Rounded disc like suckers are found on the front and rear ends.

Seen It?

Been kicking about in your local river and come across one of these invertebrates? Not sure? Share it with us at trust@forthriverstrust.org, we enjoy chatting about inverts with you.