Because the P is silent
So, before i get to the joke, you should all know that everyone in my class knows me for my shitty dad jokes and they hate me for it and today was probably the proudest moment of my life. So here's what happened.
Ecology teacher: does anyone know how to pronounce the name of this bird?
Me: willow ptarmigan (pronounced willow tarmigan. you see where this is going)
15 seconds later
Me: did you know that you can't hear willow ptarmigans go to the bathroom.
Confused classroom: what? Why?
Me: because the P is silent...
I hear the class slowly fill with groans and "oh my god"s followed by some guilty chuckles. And then, my teacher, who is about as strict and as hard to make laugh as they get, slowly sinks into her table and covers her face. And then she giggles. Just a little. This goes right up there for proudest moment of my life, next to saving a child from a burning building. Except I've never saved a child from a burning building...