To me there is only one important difference between man and animal: the mind.
That would be a useful distinction, if there were any way whatsoever to detect "the mind".
I know I have one. I assume that other humans do, because they are similar to me. I think my dog has one, because he acts as though he probably does, and (more importantly) because I like him.
But he's an animal; So according to you, he doesn't.
What objective observation can determine whether I am right (making my dog a person by your criteria); Or you are right, and he isn't?
What objective observation can determine whether a given human being, other than myself, has a mind?
What even is a mind, exactly?
How can you prove to me that you have one, and how do you know that I have one?
It seems that your "one important difference", important though it may be, is
utterly valueless in making any actual progress towards classifying who or what is "man", and who or what is "animal".