Read it through once

There is a patience of the wild—dogged, tireless, persistent as life itself—that holds motionless for endless hours the spider in its web, the snake in its coils, the panther in its ambuscade; this patience belongs peculiarly to life when it hunts its living food; and it belonged to Buck as he clung to the flank of the herd, retarding its march, irritating the young bulls, worrying the cows with their half-grown calves, and driving the wounded bull mad with helpless rage. For half a day this continued. Buck multiplied himself, attacking from all sides, enveloping the herd in a whirlwind of menace, cutting out his victim as fast as it could rejoin its mates, wearing out the patience of creatures preyed upon, which is a lesser patience than that of creatures preying.