“I’m sweating like a pig” usually means that you are pretty gross and covered in perspiration. The problem, though, is if you were indeed sweating like a pig, you’d be super dry, with not one bead of sweat on your head. You see, pigs don’t sweat. All of a sudden the popular saying becomes problematic.
1. More Irony
Some say that the phrase originates with pig iron. When heating up the metal to extreme temperatures, the ore would get hot enough to become liquid. Smelters would watch the metal for signs that it was cool enough to move and not drip everywhere. It was ready when droplets would form on the metal due to the air around it reaching dew point.
Maybe the saying has its origins with pigs, but pigs on a rotisserie. When cooking a hog over an open fire on a rotisserie, the fat from the pig would drip down into the fire. This gave the appearance of the pig sweating.
3. Stinky Sweat
It could be that the phrase came from the simple concept that sweat is stinky and gross. Pigs are also stinky and can be gross.
It is not for sure where exactly the phrase “sweating like a pig” came from, but the truth of the matter is pigs don’t sweat. Because they don’t perspire, they wallow in mud to keep cool. Lots of times pigs look super gross, and even like they are being kept in horrible conditions, but the truth is, they like the mud. Even if it is cooler, our pigs like to root in the mud and get messy.
One of the great things about hog farms, is pigs can be kept inside with sprinkler systems. They absolutely love this. It is like their own personal sweating system. There are also fans for them too. They are really quite spoiled.
Pigs may be stinky animals and enjoy getting into muddy messes, but you can’t blame them for being sweaty AND stinky, just the stinky part.