Why Do Pigs Roll in Mud?

When we become hot what do we do? We sweat, of course! But what do animals do, like pigs for instance? A pig wallows in a great big pool of mud! Why? Because the pig is hot and the mud is cool.

The Sweat & The Mud

We humans have no problem keeping our bodies at the correct temperature because we have sweat glands that secrete perspiration in order to keep our bodies at the correct temperature. You see, sweat is composed mostly of water mixed with salt and amino acids. When we sweat, the water dissipates into the air which helps cool the skin. Unfortunately, pigs can't sweat like we do because they have very few sweat glands and a barrel like, heat storing physique. So pigs and some other animals such as the rhino, the elephant, the bison and the deer have been observed rolling around in the mud in order to keep cool and prevent overheating when outside temperatures rise. Rolling in the mud can lower an animal's body temperature by 3.6 degrees Fahrenheit, making mud more efficient than sweating.

Mud Better Than Sprinklers?

Sometimes pig farmers use a sprinkler system to keep their pigs cool but mud appears to be a better coolant because the water in mud tends to evaporate slower than pure water.

Mud Makes For a Dirty Pig!

Pigs shouldn't be considered dirty animals just because they love mud. The truth is quite opposite—pigs are very clean animals, in fact, pigs keep their "bathroom" far away from their eating and drinking areas, and let's face it, most pigs would rather lounge all day in an air-conditioned barn instead of rolling in the mud, but rolling in mud does provide other healthful benefits.

Mud as a Sunscreen

A pig's pink skin is very light and prone to sunburn. In order to prevent a very unpleasant burn, the pig will roll around in the mud and use it as a sunscreen. As the mud slowly dries on their skin, a natural barrier against the harmful ultraviolet rays of the sun is created.

A Pig's Insect Repellent

Insects like bad biting flies and digging parasites are often drawn to the pig's abode because food is always near. A nice thick layer of mud helps protect the pig from insects, thus keeping them away from the pigs sensitive skin. Ticks and lice need air to breathe and cannot survive if trapped under a layer of mud and biting bugs like the fly will bother other animals if they encounter an obstacle like mud. In other words, insects do not like to wallow!

Other Wallowing Reasons

It has been suggested that wallowing animals are also marking their territories as they roll around, leaving their scent behind. This is the same for feral pigs as well as domestic pigs who rub their scent glands in or near the wallowing area in order to claim that area for their own.
Pigs and other animals like wallowing in cold weather too. Apparently a layer of mud becomes an insulating layer capable of retaining body heat! I refer to this as 'Pigs in a Mud Blanket.'

Modern Farming

In some cases modern farming has taken wallowing away from pigs by giving them air conditioned barns to keep them cool and medications to keep the bugs away. While these methods do have advantages they also have disadvantages; one disadvantage is this method is not natural. When taking natural behaviors away from animals, one should expect the consequences. Fighting may break out and behavioral changes like nipping and tail biting could occur. Removing the simple enjoyment of wallowing can stress the animal and detract from their well being, thus cultivating serious welfare issues.

By Tom Matteo

References
http://wonderopolis.org/wonder/why-do-pigs-like-mud/
http://www.pigforum.com/Why-Wallow.html
http://m.livescience.com/13953-pigs-evolved-mud-wallowing.html
http://m.phys.org/news/2011-05-wallowing-mud-temperature.html

About the Author
Tom Matteo has been a freelance writer since 1992. He specializes in hardware and software reviews for computers and gaming systems, and occasionally writes about such topics as animal behavior and care. Tom resides in Bethlehem, PA with his wife Tina and his beloved cockapoo, Angel.