Figuratively speaking in the biological sense, mammals were that fluke in evolution which against all odds of surviving prior to the impact 60 million years ago were granted that moment of truth... the opportunity to become all they could potentially be with the eradication of so many other forms present in that period's scope of biodiversity that it is all but incalcuble.
Like it or not, we all were once little scaley haired rat things scrounging around in holes trying not to be a raptors next snack.