cause football used to be often played in mud and footballs are slippery when muddy.
also, every time there is a dogpile on the football there is a lot of squealing going on.
Google is your friend.
History of the Pigskin
It may surprise you to learn that footballs wereoriginallyinflated with the bladders of animals, including those from swine. In later years, these animal bladders were placed inside a leather cover, giving rise to the term “pigskin.? The bladder of pig (or another animal) was inflated into more of an oval shape than the familiar pointed tips of today’s game balls.
The process of inflating these early pigskins was fairly distasteful as you might imagine. Straw and other material would oftentimes be stuffed in the pig bladder instead, but this tended to create balls with lumps and strange shapes that made official game play difficult.
Fortunately, blowing up pig bladders fell out of fashion for both pro and recreational football players with the invention of vulcanized rubber in the 1860s.
I think you just described the plot for the movie Deliverance