The Probert Encyclopaedia of Nature

LEECH

Leech is a popular term for annelid worms of the class Hirudinea comprising those worms equipped with a sucker at each end that draw blood from their prey (warm blooded mammals), such as Hirudo medicinalis. Leeches live in hot, swampy areas particularly in stagnant water and feed on the blood of passing mammals. Pulling a leech off can result in the jaw being left in the skin, and an infection resulting. The prefered method for removing leeches in the wild is to touch them with the lighted end of a cigarette, causing the leech to release its grip and drop off.
Research Leech