I know that this question may sound silly, that it may look like the asker is just trying to acquire attention, that it may seem as if by one's asking this question one is partaking in something absolutely ridiculous, but I ask this question in the most honest, earnest, and loving way possible.
I ask it because today I came across something called 'species dysphoria'. The only 'dysphoria' with which I can say I am quite familiar is gender dysphoria because I am a cisgender ally of the transgender community and one who believes that one can really be a transgender person --- rather than being a person who believes oneself to be transgender but is in reality just a mentally disordered person.
Some human beings seem to be most sincere when they say that they identify not as human beings. How can a human identify as a non-human? How could a human be a non-human? Of course, some would say that a human individual is defined by the properties that one possesses - the capacity for articulate speech, the ability to reason and the like - but that is very essentialist and one could use that argument against transgender people by saying that a man is a person who has an XY chromosomal pattern, a penis, and the like.
I, for example, believe not that when a transgender person says that they are X in the body of Y that they mean it literally. I see not how one could be X in Y's body. But I do see how that could be a metaphorical way for one to describe to cisgender people how one feels about what one believes to be one's sex and gender mismatch.
So can one who is a human be a non-human in a human being's body. If so, how?