Have The World By The Tail Meaning

(idiomatic) To possess great influence and opportunity.

Example: 1919, William MacLeod Raine, A Man Four-Square, ch. 15:
  "Webb thinks he's got the world by the tail for a downhill pull. I'll show him."
1938 Feb. 28, "Give Us Colonies!!," Time (retrieved 7 August 2013):
  No nation had the World by the tail this week, but the rear end of the British lion was within measurable distance of Adolf Hitler's grasp.
1992 Sept. 24, Sara Rimer, "Company News: Hearing the Fears, With No Answers," New York Times (retrieved 7 August 2013):
  "You think you're set. You think everything's taken care of. I thought I had the world by the tail."