Wednesday, November 30, 2011

Why Do Earthworms...

...try to commit suicide?

Surely you've witnessed this too. Almost every time it rains, especially a warm rain, earthworms come streaming out of the ground and onto any paved surface they can find where they promptly dry up and die as soon as the rain stops. Are they leaving the soil because it's too saturated and they think they might drown? Well, that's dumb because they're gonna die anyway on my driveway, either by dehydration or getting snatched by a hungry bird. If any of you readers know why they do this, please enlighten me.

Yesterday I staged an intervention. Overnight we had several inches of rain, after which I woke up to find numerous worms in the garage (safe from birds but still a death sentence) and a driveway absolutely covered with them. Now that we have a compost pile (currently just shredded leaves and coffee grounds) it occurred to me to pick them all up and toss them in, saving their lives and improving the quality of my dark matter. Jeff and I easily picked up over 40 earthworms and carefully distributed them in the bin.

While investigating what to add to the compost pile, I read that earthworms absolutely love coffee grounds and I've been getting big bags from Starbucks of their used grounds (called Grounds For Your Garden) to add to my mix. If you have a compost bin, you may want to check your local Starbucks and see if they participate in this program.

I hope they find their new life in my bin worth living.


  1. Boy, if anybody has the answer to this one I sure would like to know it! Good answer you came up with...I shall emulate you next time!

  2. I found two answers on the Internet:

    Dr. Dennis Linden, Cindy Hale, and other worm experts say that worms do NOT surface to avoid drowning. In fact, they come to the surface during rains (especially in the spring) so they can move overland. The temporarily wet conditions give worms a chance to move safely to new places. Since worms breathe through their skin, the skin must stay wet in order for the oxygen to pass through it. After rain or during high humidity are safe times for worms to move around without dehydrating. It is true that, without oxygen, worms will suffocate. But earthworms can survive for several weeks under water, providing there is sufficient oxygen in the water to support them.


    They are often seen above the ground after a heavy rain. There are many theories about this behavior of earthworms. One opinion is that the amount of oxygen dissolved in water is less than that in the air. So, earthworms come above ground when their burrows get filled with rainwater. However, if sufficient amount of oxygen is dissolved in the water, they can live underwater for many days.

    Another supposition is that the humidity after rain is high, and therefore the earthworms come out as the high humidity protects their skin from dehydration. Besides, they can also move faster on the moist surface, and therefore reach new places for populating. Another reason for coming above ground may be the fact that due to respiratory activities of organisms living underground, the level of carbon dioxide increases. This carbon dioxide forms carbonic acid with rainwater. So, to avoid such a harmful acidic environment, they come out to the surface.

    End answer: "not sure"

  3. Yeah, I agree with "end answer".

  4. Interesting theories, though! Thanks for searching it out, Ellen!

  5. Earnest Lee InquiringDecember 1, 2011 at 7:22 AM

    Is it considered showing-off if your reply is longer than the original post?

  6. Professor Ed U. Cated PHD, MBA,FDIC,December 1, 2011 at 7:28 AM

    Technically no, especially if the post includes a photo of a woman holding a handful of worms.

  7. Thanks everybody for responding!

    Those are some pretty interesting theories, Ellen. I can't believe somebody actually had an answer!

    It's pretty fascinating that we can explain things like String Theory and Black Holes, but no one knows for sure why worms surface during a rain.

  8. Interesting theories, but then, why do the worms come into the garage, where it is DRY? Is it by accident, and then they get stuck there?

  9. Steve, I still have no idea! I guess it's just one of life's unanswerable questions...kinda like "Why isn't there mouse flavored cat food?" or "Why did kamikaze pilots wear helmets?"

  10. Great article with excellent idea! I appreciate your post.

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