Interesting Facts about Annelids

Annelids may just seem to be ordinary worms with little merit but in fact, they do some pretty remarkable things. Here are some interesting facts about segmented worms

1. Earthworms (Lumbricus terrestris) are some of the most important creatures in our enviroment. They dig through soil and help aerate it, while at the same time grinding and digesting incredible amounts of soil through their guts and returns many important nutrients back to the earth. In fact if all material that has moved through an earthworm was piled on the surface of the globe, it would accumalate to more than 30 miles, five times more than Mount Everest.

(a drawing of burrowing earthworms)

2. Leeches (Hirudo medicinalis) have been used for medicinal purposes for a very long time. Back then, it was believed that leeching would get rid of the "bad blood" that caused diseases. However when scientists began to understand the nature of diseases and that it was caused by micro-organisms, leeching fell into obscurity. Now, leeches are back in the medical spotlight. The chemicals they produce that stops blood from clotting and anesthetize the area the bite can be used to remove blood clots. Also the chemicals also harm bacteria by dissolving their protective coating. Guess leeches arn't so bad after all!

(medicinal leeches in a jar)

3. Ever wonder what those wierd piles of sand on the beach are? Well they are actually the castings of a polychaete called the sandworm /lugworm (Arenicola marina). They are similiar to earthworms as they dig through the sand and digests it. The indigestable sand takes about an hour to pass through its entire body and comes out at the other end. The worms then move backwards through the tunnel and their cylindrical castings are pused out of the burrow, which forms the shapes that we often see on the beach.

(lugworm castings)