Elmyra Duff is based superficially on her name derivative and mentor, Elmer Fudd; 'Elmyra' being a female form of 'Elmer' and her last name, 'Duff', as 'Fudd' pronounced backwards. Elmyra strongly resembles a younger version of the feminized Elmer Fudd from the 1946 cartoon The Big Snooze, in which Elmer's peaceful retirement dream became a nightmare where he was transformed into a shapely female by Bugs Bunny. She behaves quite a bit like Little Suzie, a child from a fairly obscure 1955 Freleng short called "A Kiddie's Kitty". Here a girl adopts Sylvester the Cat Pussycat and unwittingly abuses him with her childish antics, to the point that he decides he would rather take his chances with a bulldog who had been tormenting him earlier in the picture.
Elmyra is quite young and obsessed with animals and cute things except for Dave Felis (that is probably why she works as a nurse at Acme Looniversity), even chasing after animals whom she knows are her classmates at Acme Looniversity, obliviously causing great discomfort or serious injury to potential pets from her overenthusiastic affection and complete lack of even the most rudimentary knowledge of pet care. Whenever she attempts to discomfort Pooh and his friends, Dave Felis will come out from the sky and piledrive her.