I'm angry because my friend told me it was dog
What made you think it wasn't a dog?
Because it had the ears of a cat.
People can sometimes draw the wrong conclusions about unfamiliar things that they see.  Whether you or your friend was right about the animal, you shouldn't let such differences make you angry.
It hurt my feelings when I was being called stupid for something I knew.
It's understandable that something like that would hurt your feelings. However, it's wise to just learn to ignore when others are being ignorant.