Obviously it was a challenge, but Alcatraz was too happy in his new-found brothers to think of battle.
He ducked his head a little and pawed the ground lightly, a horse's age-old manner of expressing amicable intentions.

But there was nothing amicable in the black leader.

He reared a little and came down lightly on his forefeet, his weight gathered on his haunches as though he were preparing to charge, and at this unmistakable evidence of ill-will, Alcatraz snorted and grew alert.
If it came to fighting he was more than at home.

He was a master.

More than one corral gate he had cunningly worked ajar, and more than one flimsy barn wall he had broken down with his leaning shoulder, and more than one fence he had leaped to get at the horses beyond.