In 1994 I saw the documentary 'Cougar: Ghost of the Rockies'. I particularly remember the beginning where a cougar weighing perhaps 60kg took out a deer three or four times the cat's weight. The stalk, final charge and bite to the neck were so clinical. I was impressed with the cat's explosive power and final pounce. I usually don't like to see animals suffering but I think in this case the suffering wasn't prolonged.
I couldn't find the full film for free but could find the beginning (below).
What do you think?