Earthworms and Digestion

What about the earthworm?

The body of an earthworm seems simple; upon further investigation it’s ugly too. There isn’t much to it and it looks too fragile to have existed on this earth for as long as it has, 120 million years. Darwin started studying them in 1809. They have survived the survival of the fittest in that they have not gone extinct, not yet anyway.

Nightcrawlers or Earthworms are creatures that consist of a complex internal system.


Digestive System

An Earthworm’s digestive system is one of the most important features of the worm. It consists of mouth, pharynx, esophagus, crop, gizzard and intestine. The mouth is surrounded by strong lips that act like a hand would. He searches for dead grass and bits and pieces of leaves and weeds. Once he finds food the lips break the food down into smaller pieces. Since an earthworm does not have teeth, bits of soil particles are used to help them “chew” their food.

The food particles pass from the mouth to the pharynx where the food is lubricated by mucus secretions. This makes it easier to pass along to the esophagus where calcium carbonate is added to the mixture. Calcium carbonate is used to neutralize the acids that are formed once the food matter decays.

Next, the food is temporarily stored in the crop where they will get mixed together. From the crop, the mixture enters the gizzard where the actual digestive process begins.

Worm Facts

  • The study of worms is called helminthology.

  • 90% of their body weight is water weight.
  • They have five hearts
  • There are thousands of different kinds of worms
  • There are four main groups of worms
    • Flatworms, or Platyhelminthes;
    • Ribbon worms, or Nemertea
    • Roundworms, or Nematoda; and
    • Segmented worms, or Annelida.

The powerful muscles of the gizzard churn and mix the mass of food and dirt. The mixture is reduced to a thick paste once the churning and mixture is complete. Glands in the walls of the gizzard add enzymes, which aid in the chemical breakdown of the organic material.

Next, the mixture is sent to the intestine. The intestine has friendly bacteria that eat the food mixture. While the mixture is being eaten it releases various vitamins, minerals, carbohydrates, and proteins from the organic matter; this supplies everything the worm needs in order for him to absorb it into his body.

Most of the worm’s body length is intestine. It is lined with thousands of finger-like projections that are filled with small blood vessels. The blood vessels help to absorb the liquefied food.

Finally at the end of the intestine, the soil particles and undigested organic matter pass out of the worm’s body through the anus. The waste is deposited in a form called a worm cast. The worm cast is mostly just ground up soil. By the time it comes out of the worm it has become enriched, acid neutralized, and revitalized. This is why so many people want to learn about vermiculture, or how to culture a garden/waste reduction using worms. Worms and their digestion help to fertilize the soil and grow our food!

Now that you know all about the earthworm and its digestion, learn about earthworms and reproduction.

Earthworm movement

In addition to the Web sites I listed I also got information from "The Nightcrawler Manual" by Ray Edwards.

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Comments 40 comments

Uncle Oswald 8 years ago

Eww! Gross.

Zsuzsy Bee profile image

Zsuzsy Bee 8 years ago from Ontario/Canada

Pretty good explonation.

great hub regards Zsuzsy

Rebecca 8 years ago

wow, I was just wondering how a worm digested its food and then your article came along! Thanks for the information! Are you a helminthologist by any chance?

zannr profile image

zannr 8 years ago from Portland Author

I wish I was a helminthologist!

JPSO138 profile image

JPSO138 8 years ago from Cebu, Philippines, International

Very interesting. I am learning from your hub! Nice.

antonette 8 years ago

nice answer...i like it so muchhhhhhhhh

Kasey 7 years ago

Wow you just helped me complete my zoology questions

thank you

harry u. 7 years ago

thank you now i really understand what i am laerning about and how fasinating creatures are!!!!!!

alena perez 7 years ago


ali j yo 7 years ago

so what's up with these people?

worms are disgusting but are very interesting that is the only reason.

and i agree with every person that say that this vid is very disturbing

Anonymous 7 years ago

Thnx for the help on bio!

theo 6 years ago

I love hub, it is very iteresting

Katie 6 years ago

I love that video!!!! I don't know why everyone says that it is disturbing.

Milan 6 years ago

the video is pretty awesome it looks like skin folds


John 6 years ago

ty for the great detail, needed it for an assignment

unknown 6 years ago

thanks, we are takin this stuff in science and i don't want to read 3 pages for one answer

James 6 years ago

Great information! Needed for an assignment so thanks!

neha 6 years ago

i found it really interesting.

taiga 6 years ago

Thank you for the information. I'm having a science fair project and this really helped me with the report I'm doing for it. i really thankful O.-

ramzan42 6 years ago

Marna - I know my husband was looking around for some manure for his worms. He thinks he found someone with horses who will give him some for free. If this does turn into a good business, the overhead will definitely be small! Thanks for reading and commenting!

Keshav gautam 5 years ago

I want to learn many more about the digestive gland of earthworm

Dan 5 years ago

Darwin had no idea what he was talking about in the 19th century. We are now learning that even the organisms as simple as an earth worm is a complicated fully functional organism. This article states that worms and their digestion help to fertilize the soil and grow our food..interesting....why would a worm want to do that if it just wants to survive? unless there is an intelligent creator behind it, Who has wired everything together and made it beneficial for humans to reside...

Tween 5 years ago

Thanx this is exactly what i needed for my assignment

casez 5 years ago

very good! thanks!

Anne 5 years ago

Thanks for this very informative article about earthworm and its digestion. I like that! Thanks for sharing.



anoynomous 5 years ago

nice work

anil 5 years ago

earth worms are looking good for bipc students

gaurav 5 years ago

i think earthwarm is very useful in biology but i asking evry scientist what is need of earthwarm in bio give actual reason...i don't know

annie bananie 4 years ago

that's so weird ! it didn't answer my question though, r u gunna make another site

cupcake 4 years ago

thanks for the useful info on worm's digestive system!!!

Worm 4 years ago

You are excatly right about us

Adam 4 years ago

Very interesting

Nick 4 years ago

gygy v

Bobby M. 4 years ago

The worm is amazingly interesting that is why i am studying it in school. This website is very helpful thank you. I hope to use it more often, i will tell all of my friends and relatives about. I believe that in a year this website will be as popular as facebook. GO bears! I believe Miami is the nicest place to go for vacation. i use to be a senator. haha jk. Don't worry i am not a senator.

amna shafqat 4 years ago

awesume and very helpful

Gumpy 4 years ago

Guy,u realy help my studentship....with this i hope Mr.Johnson Joseph will b satisfy.Thank you very much.iam happy indeed

nikhil 4 years ago

thanx 4r helping in bio

TED 3 years ago

this didn't help at all!!!!!!!!

fuuu 2 years ago

i no bia!! fvf

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