So, this joke works only for natives who know that calf is not cow.
A funny riddle is a j-o-k-e that sounds like “joke”.
You sit in the tub for an s-o-a-k that sounds like “soak”.
So how do you spell the white of an egg?
// All of these prove humans are subject to "context priming".
(I suppose my context was primed both by your brain-teaser, and also the fact that we've been talking about these sorts of things. If you'd said this to me out of the blue, I probably would have spelled out all of "yolk" and thought it was correct.)
Many people use cow to mean all bovines, even if technically not correct.
Come on now :0
I just complained non-natives would have a problem distinguishing between a cow and a calf, and you had to bring those bovines.
To make it easier, would just drop that in my native language, the correct term for bovine is more used to describe people with certain character, that animal kind.