Because they croak a lot!
croaky voice) ROBBERT
Sure, you know how it works, but now it's dead.
NURSE: ...his heart ME: Hm. NURSE: Your resume said you were a surgeon ME: My resume says a lot of things
A: The White House.
brucism
Because a frog croaks all the time but a cat only gets to croak nine times !
He simply croaked !