Even a buffalo separated from the herd has reasonable chances. At one point we saw a lone bull that was trying to get back to the herd, which was about a half mile away. In between him and the herd were four lionesses, sacked out asleep. This looked like the perfect opportunity for a kill, but the buffalo surprised both us and the lions. He crept up on the sleeping lions, then when he got close he lowered his horns and charged. The lions awoke, panicked and scattered into the bushes. The buffalo then trotted victorious back to the pride. It was a perfect illustration of the adage that the best defense is a good offense.

This essay carries the following warning at Edge.org:

WARNING: some of the photos are a bit gory, and one shows explicit lion sex.

See also the latest research on fight-or-flight, using fMRI on video-game-playing humans.

You may also be interested in Wildebeest vs. wild dogs.

Lions: Africa's Magnificent Predators | By Nathan Myhrvold