A What?

Can you guess what animal I am?

A WHAT?

What feels with its mouth,
and watches with its ears,
and will go with just a nudge
through tame or wild frontiers?
What gold will glow in sunlight
and shine beneath a hand
and steps into the rarified air
with the slightest leg command?
What knows your every movement,
and can sense your every fear?
What knows when you are happy,
and when there's carrots in your gear?
What loves you when you're ragged,
and when your clothes are torn?
What loves you not for how you look,
but for the love that you have sworn?
What has an eye that glitters
like the dew that coats the park
that nothing can diminish
not even the darkest dark?
What wonders when you leave it
at the gate wet-backed and spent,
what do you do without it,
and where the heck it is you went?