Stephen London, age 9, of Keen, N.H., for his question:

WHERE DOES THE LEECH LIVE?

The leech, also called a bloodsucker, is a worm that has a disk like sucker at each end of its body. Leeches live in damp places such as jungles, or in the shallow water of streams, lakes or oceans.

Some leeches live as parasites, sucking on the blood and tissue of other animals for nourishment. Others feed on decaying animals and plant material.

Parasitic leeches attach to their victim with the front sucker, make a wound and then suck out blood. Bloodsucking leeches give out a liquid containing a chemical substance called hirudin. Hirudin prevents the blood from thickening and makes it easier for the leech to suck blood.

At one time, leeches were used to help heal bruises and cure diseases: Doctors were then using what was called medicinal leeches. This was supposed to remove bad blood. Medicinal leeches are seldom used today.

A leeches body is made up of a series of ringlike segments. Leeches may be less than an inch long or up to eight inches long. A leech contains both male and female reproduction organs.