what was bucks seven duties at judge millers estate?

"But Buck was neither house dog nor kennel dog. The whole realm was his. He plunged into the swimming tank or went hunting with the Judge's sons; he escorted Mollie and Alice, the Judge's daughters, on long twilight or early morning rambles; on wintry nights he lay at the Judge's feet before the roaring library fire; he carried the Judge's grandsons on his back, or rolled them in the grass, and guarded their footsteps through wild adventures down to the fountain in the stable yard, and even beyond, where the paddocks were, and the berry patches. Among the terriers he stalked imperiously, and Toots and Ysabel he utterly ignored, for he was king--king over all creeping, crawling, flying things of Judge Miller's place, humans included."