[@harinezumikouken]

Obviously, Shiro is not a normal tiger faunas.

He's actually a human faunas, and is primarily a tiger. Just as pops was trying to figure out if he could turn Faunas into humans, someone, somewhere, was trying to turn animals into faunas. Shiro is a product of such an experiment and why he has so many animistic traits for a faunas, because he was once a normal animal, now in humanoid form.

And nothing has been said to deny my hypothesis, and thus it may as well be canon.