If You Cut a Worm in Half Will it Become Two Worms?

worm, earthworm, cut in half, regenerateIf it is an earthworm, most likely the answers is no.  Contrary to what you may think, earthworms do not have the ability to regenerate.

I remember hearing that if you cut a worm in half it would be able to grow into two new worms.  Somehow I never tested this theory, but I remembered it recently after a rain.  I did some research and discovered that while earthworms do not have the ability to regenerate, some other worms do.  Here is what would happen if you cut a regular earthworm in half and what worms can actually regenerate.

About Earthworms

It may not look like it, but earthworms have a head and a tail.  Their body is mostly flat and smooth except for a bulge in their body that looks like a rubber band is wrapped around it.  That bulge is called the clitellum.

Most of the earthworm’s important organs are located near the head and above the clitellum.

worm, earthworm

An earthworm. Look at the bulge that is the clitellum.  Photo Flickr by Veronica Kocianova.

What Would Happen If you Cut an Earthworm In Half?

What would happen to the worm really depends on where you cut it in half.  If you cut an earthworm in half above or on the clitellum it will not be able to survive and will die.  However, if the worm is cut below the clitellum then the part with the head will be able to grow a new tail.  The old tail that now has no head though will not be able to grow a new head and would die.

Are There Any Kinds of Worms That Can Regenerate?

Yes, flatworms or to be precise a planarian flatworm.  This flatworm can regenerate and grow a new worm if it is cut in two or more pieces.  It has a remarkable ability to regenerate from a small piece of its original body.

It’s ability to regenerate has made it important for scientists to study.  Scientists are trying to learn how regeneration works with the hope that someday they may use it to help people.