Time and again, for centuries - with the pace picking up dramatically in recent decades - we thought we were special and we were wrong. Sun does not rotate around the earth, which is a pretty typical planet, with the same chemical composition of any other planet. All of a sudden we're not the only ones who could calculate, then solve symbolic equations, then play chess, then compose music, then talk, then reason (up to a point, for some definition of "reason"). You get my point.
And when we were not only matched, but dramatically surpassed in these tasks (and not a day earlier), we concluded that they weren't _really_ what made us special.
At this point, it seems to me reasonable to assume we're _not_ special, and the onus should be on anybody claiming that we are to at least attempt to mention in passing what is the secret sauce that we have (even if we can't quite say what it is without handwaving or using concepts that by definition can not be defined - "qualia is the indescribable feeling of red - its redness (?)).
Oh, and sorry, I could never quite grasp what "sentient" is supposed to mean - would we be able to tell we're not sentient if we weren't?
Spooky stuff.