Have you ever heard anyone say that he is sweating like a pig? What goes through your mind when you hear this said? Do you picture Porky Pig roasting out in the sun with a headband on to catch the sweat before it drips into his eyes? Maybe you imagine a bunch of pigs in a pigpen fighting with each other over the scraps that have been thrown to them, but they are having problems grabbing hold of each other because they are so slick with sweat.
Front view of ladle emptying molten iron into moulds, pig iron machine, Pittsburg, Pa., U.S.A.
When you sweat like a pig, you are sweating excessively. Your hair, body, and clothing are probably so wet that you look as though you have been outside during a massive rain shower or thunderstorm. Is that really how pigs sweat?
Most have the idea that pigs are dirty, nasty animals because they like to wallow around in the mud. But they have a good reason for doing this. Did you know that pigs don't really sweat? That's right, the few sweat glands they have (humans have over 2 million) don't work very well. So how do they cool off? Staying dirty isn't really a preference for them, it is the means by which they cool down. Mud and water effectively bring their body temperature down to a comfortable level. So when we say that someone is sweating like a pig, are we saying that he is wallowing around in the mud? Not exactly.
Since pigs don't really sweat, where did this phrase come from? It has absolutely nothing to do with the animal that wallows in the mud. Instead, it has to do with the process of iron smelting. The ore is the native metal or rock. When you smelt it, you melt it to remove the metal from it. Hot, liquid iron is poured into molds that resemble a sow with her dozen or more nursing piglets. Nope, that wasn't exactly the first thing that popped into my mind, either.
Anyway, in these molds it is made into something called pig iron. What is pig iron? It is a brittle form of iron that doesn't really have many uses. In order for it to made into this, however, the temperature has to get extremely hot, too hot for it to be moved. How do they know when it is cool enough to move? Droplets of moisture will form on the metal's surface; it will sweat like a pig.
For a writing exercise with this common phrase, why not write a children's story that shows where this saying really comes from?
Now that you know this phrase has nothing to do with pigs, will it help you to use it more effectively in your writing?