@fudge_the_sphinx
I very much agree with you that mental abilities aren't inherent to specific species. Claiming our level of intelligence as human is the epitome of humanity's arrogance. The fact of the matter is that we simply can't know and have to rely on observations which will always be centered around our perspective, because we don't know anything else.
My perspective on this isn't to categorize mental aspects as human and nonhuman, but rather to assume the view of a neutral outsider and compare how much my actions and behaviors align with those of humans.
That's what I meant by "Animals don't sit in front of a computer and have discussions about identity and concepts": because they don't, at least not the way humans do.
I steer clear of any assumptions and just go by what's observable. And that gives me pretty good indications about whether I'm mentally closer to a species of animal or humans.
As for the desire to be an animal, my line of thinking is as follows:
Desire means to wish for a state that currently isn't true. If I want to drink water, it's because I'm thirsty and I want to enter a state where I'm not thirsty anymore. Similarly, I want to be an animal because my current existence is not being an animal. If I already were an animal, I wouldn't feel this desire. This is why to me it feels like an affirmation of my humanity.
The answer to this question generally doesn't really matter to me either. It only came up once I looked into alterhuman communities and saw them being characterized as "we all have nonhuman identities in common". Joining would force me to give an answer (not even to the community, but to myself), and then I have to know if I stand behind it.
Volpeon (Bonus) 
@volpi@icy.wyvern.rip