The down-coming winter was harrying them on to the lower levels, and it seemed they could never shake off this tireless creature that held them back.

Besides, it was not the life of the herd, or of the young bulls, that was threatened.

The life of only one member was demanded, which was a remoter interest than their lives, and in the end they were content to pay the toll.
As twilight fell the old bull stood with lowered head, watching his mates--the cows he had known, the calves he had fathered, the bulls he had mastered--as they shambled on at a rapid pace through the fading light.

He could not follow, for before his nose leaped the merciless fanged terror that would not let him go.

Three hundredweight more than half a ton he weighed; he had lived a long, strong life, full of fight and struggle, and at the end he faced death at the teeth of a creature whose head did not reach beyond his great knuckled knees.
From then on, night and day, Buck never left his prey, never gave it a moment's rest, never permitted it to browse the leaves of trees or the shoots of young birch and willow.