Flea droppings . . . eewwwww . . .

I was middle-aged, and researching "earthdogs," before it was ever
explained to me why skunks have what they have.

It's all about tunneling underground.
Above-ground, the skunk's defense is reduced to a notorious stench.
Senoufou, in the US there was a song about
"dead skunk in the middle of the road,"
which is where most people smell their first skunk smell;
skunks are also notorious for strolling across the road and getting run over.

Ah, but underground ... skunks are good diggers, and they favor holes.
Some predators follow the skunk down said holes.
And there, a predator following the skunk's tail, in a confined space,
can -- and has literally -- smother to death from the smell.

Terriers have in fact died of it.