No, that would mean something different. You could say "the animal is a duck" when you've determined the species of the animal (notice the definite article), and that statement could be false (if the animal is actually not a duck). "A duck is an animal" is a fact, and can never be false.
Unfortunately, we are not able to affect Duolingo's underlying correction system. The general rule is that you're allowed one typo per word, as long as this doesn't turn the word into another word. So since Duolingo sometimes thinks that Swedish words don't count (like har, here), and since it also thinks that a and ä are the same letters, you're being let through with a typo. It's detrimental to people's learning, and certainly not something I like, but not something I have influence over.