Wouldn’t it be cool if your parents allowed you to wallow around in a big puddle of mud all day long? As a matter of fact, that’s EXACTLY what it would be. Just ask a pig. Mud is cool!

When humans get hot, we sweat. Our bodies need to stay about the same temperature — 98.6° F — all the time.

To keep our bodies at the correct temperature, our sweat glands secrete sweat (also called “perspiration”) when we get hot. Sweat is mostly water with small amounts of salts and amino acids.

As you sweat, the water evaporates into the air and cools the skin beneath it. Unfortunately, pigs have very few sweat glands, and the ones they do have don’t work very well.

As a result, pigs can’t sweat like we do. So what’s a pig to do when it gets hot?

You guessed it: Wallow in the mud! Rolling around in the mud helps to keep pigs from overheating when it gets too hot outside.

Some pig farmers now use water sprinklers instead of mud to keep pigs cool in warm months. Mud, however, tends to keep pigs cooler longer because the water in mud evaporates more slowly than pure water.

Just because pigs like to roll in mud, don’t assume that they’re dirty animals. To the contrary, pigs tend to be very clean animals.

For example, if you spend much time around a pig farm, you’ll find that pigs keep their “bathroom” as far away as possible from the areas where they eat and drink.

If given the choice, pigs would probably prefer to stay in an air-conditioned barn rather than roll around in the mud. Since they spend a lot of time outside, though, rolling in the mud does have other benefits.

You’ve probably noticed that most pigs are not very tan. In fact, their light pink skin can get sunburned very easily.

To help protect their skin from sunburn, pigs use mud as a form of sunscreen. When mud dries on their skin, it forms a barrier against the sun’s harmful ultraviolet rays.

A good thick layer of mud also helps to protect pigs from insects. Flies, parasites and biting insects are often drawn to the areas where pigs live since there is often food nearby. Mud helps to keep harmful insects away from pigs’ sensitive skin.


36 Join the Discussion

1 Star2 Stars3 Stars4 Stars5 Stars  (32 votes, avg. 4.09 out of 5)
  1. I know other animals that like the mud like rhinos and hippos. I am surprised that in the video at how much water was in the mud.

    • You are RIGHT about rhinos and hippos, Tommy! Thanks so much for sharing those “cool” extra facts with all of your Wonder Friends today! :-)

  2. Hi, it’s Julia! I am 10 years old. I learned about this website at school during science. I am loving your videos. I am in fifth grade. I have a sister and a brother, too. My sister is 8 and my brother is 4. His name is Arthur. My sister’s name is Grace.

    • It’s very nice to meet you, Julia! Thank you so much for visiting Wonderopolis and for sharing about yourself and your family! Have a WONDERful day! :-)

    • Thank YOU for visiting Wonderopolis today and for letting us know how much you liked the video about MUD, Andrew! We appreciate your comment! :-)

    • Rolling around in mud DOES sound like messy fun, doesn’t it, Trinity? Just ask all the people in the video for today’s Wonder of the Day®! Have you ever been to a big mud puddle party like that? We think it would be a blast to get so muddy with family and friends! :-)

  3. What a fun mess that video was!! Yesterday a few of us got dirty playing outside and got into trouble with our teachers. I bet we would have really enjoyed wallowing in the mud on “Mud Day.”

    We didn’t know that pigs wallow in mud to protect themselves from insects and the sun. We didn’t know that pigs were really clean animals either. We also learned that pigs don’t sweat and that mud keeps them cooler than plain water would.

    It’s funny…. We say “I’m sweating like a pig!” but pigs don’t sweat!! Seems as if our similie is not correct! We wonder what we should say instead? “I’m sweating like a gorilla!” or “I’m sweating like an old man!” hahahahaha :)

    • You amaze us with your AWESOME comments every day, Kerrick Elementary School! We love that you take the time to experience each Wonder and then tie it back to your own personal experiences! We also enjoy hearing all the things you learn from each Wonder! We hope the “explorers” who got dirty playing outside yesterday didn’t get into too much trouble! :-)

  4. We looked up Mud Day and found out where it is held (Michigan). That is close to us so we may talk to our parents about it. Better yet, maybe we can talk to someone in our city about having our own mud day. Many of us knew that pigs rolled around in the mud to keep cool, but we did not know about using mud as sunscreen! Tommy from our class knew about both of those facts and more! Thanks Wonderopolis for the great video!!

    • WOW! That would be so cool if you could get a mud day in your own city, The Beach (Mrs. Guerin’s 2nd Grade Class)! Let us know how that goes…we’d love to hear about your experience! Thank you for another AWESOME comment! :-)

    • Wasn’t it fun to learn one reason WHY they are so dirty by exploring this Wonder of the Day®, Zaid? Thank you for sharing your comment with us! :-)

    • We really do appreciate when our Wonder Friends let us know what they’re WONDERing about, Sara! We take every Wonder nomination and idea very seriously! We wonder all the time, too! :-)

  5. We liked learning about pigs! We are wondering how cats keep themselves cool. We also wonder: why will pigs eat anything?

  6. I agree with Kyle, the video was funny! :-)
    The pig in the video looked like it wanted attention or wanted its belly rubbed. :-)

    • Thanks for sharing your thoughts about the video for this Wonder, Julie! We WONDER what it would be like to be a pig for a day and get to play in the mud to cool ourselves off. We bet it would be lots of FUN! :-)

    • Great Wonder, Friends in Mrs. Foster’s Class! It depends on how hot it is outside, since the sun is what helps mud dry and become dirt! We Wonder if you can do some more research of your own about how quickly things can bake in the sun! :)

    • Great point, Pig Girl! We like your style– we loved learning about how pigs use mud as sunscreen to keep them safe and happy! We are so glad you shared what you learned, Wonder Friend! NICE WORK! :)

  7. We learned that pigs roll in the mud to stay cool. We also learned that they roll in the mud so they don’t get bitten by insects and for sunscreen. We are reading Charlotte’s Web so we wanted to learn about pigs. It’s cool that they stay cool in the mud.

    • Who knew that mud could be so cool?! Thanks for joining us today, Mrs. LaLonde’s Class, we think it’s oink-tastic that you are reading Charlotte’s Web and WONDERing about pigs! There sure is a lot of fun at the farm, especially in that WONDERful book! Pigs don’t just like to play in the mud, it’s how they keep their cool. Thanks for sharing what you have learned today, Wonder Friends! :)

    • Hey there, Haylee, what a great question! Pigs are hungry animals, and sometimes they eat what’s around them! Oink oink! Thanks for WONDERing with us! :)

  8. your were so correct about pigs.Pigs keep their bathroom and toilet area away from their eating areaThanks for wondering with me$

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>


  • Wonderopolis on Facebook
  • Wonderopolis on Pinterest
  • Print

Have you ever wondered…

  • Why do pigs like mud?
  • Are pigs dirty animals?
  • Do pigs use sunscreen?

Wonder Gallery

Try It Out

Ready to get muddy? Check with an adult first and then get your old clothes on. We’re going to cook up a fun outdoor treat that’s a childhood favorite: mud pies!

Just like regular recipes, mud pies can include many more ingredients than just dirt and water. Check out these neat ideas for making mud pies before heading outside. You and your parents can even set up your own outdoor mud pie kitchen.

If you want to have some fun making some more earthy art projects, try out these fun and easy clay activities:


Still Wondering

Illuminations’ Pigging Out lesson uses the story of The Three Little Pigs to motivate students to think and reason mathematically in a number of ways.


Wonder Categories/Tags

Wonder What’s Next?

Happy New Year! What are we talking about? Find out tomorrow in Wonderopolis!

Upload a Photo or Paste the URL of a YouTube or SchoolTube Video.