The Leech

Believe it or not, there are farms where people raise leeches! And did you know that some leeches are used in medicine? Learn more about this icky member of worm world.

-- There are over 600 different kinds of leeches. Most are blood-sucking parasites. That means they live in or on other living things. 

-- Leeches have a chemical that prevents blood from clotting. That enables them to suck blood without worrying that the blood clots. Sometimes blood clots occur in humans when they are not supposed to. That can be dangerous, so that's when a doctor might use a leech. 

-- Leeches are attached to the area where the doctor wants the blood to flow again. There's an anesthetic in their saliva so the bite doesn't hurt. 

-- Leech therapy has even helped doctors graft tissue (skin) and re-attach missing fingers and toes. You see, the only way that the body attachment will survive is if blood flows to it.

-- Leeches can grow from a skinny little thing to a big round one filled with blood. In 20 minutes they can absorb five times their weight in blood. 

-- When their suckers on each end can no longer hold on, they pop off, leaving behind a telltale triangular bite. Unlike other parasites, they only hang on for a short while and then let go and move on. 

-- Leeches don't eat often. They can keep blood cells in their guts for up to 1 1/2 years.

-- The leech and earthworm are both segmented worms. But an earthworm, will add on segments as it gets older until it has over a hundred. When a leech hatches, it has 32 segments and will always have 32.