Originally Posted by Theo The Theologian

Do you wonder why the expression "Sweating like a pig" is used to say you are very hot, and sweaty?
This is a strange expression as it's a well known fact that pigs have no sweat glands at all, and thus cannot sweat.
This is also why pigs spend most of the day in mud puddles.
It's not because they like mud, they are simply trying to keep cool.
Humans on the other hand routinely sweat as a way of eliminating excess heat, and to maintain normal body temperature.
The average person has 2.6 million sweat glands. I should point out however that even though we have 2.6 million sweat glands, none exist in the lips, or nipples.