I read this article today that big cats are facing extinction in National Geographic. I had no idea that this was a big problem, so the article was surprising: http://newswatch.nationalgeographic.com/2014/08/07/big-cats-at-a-tipping-point-in-the-wild-jouberts-warn/
There were apparently 450,000 lions fifty years ago and 20-30k today. It is correlated to our population growth. Apparently, for every billion people the earth adds, the lion population drops 50%. The same is true for leopards, cheetahs, and snow leopards. The article points out that poaching is a problem and that a general degree of misinformation that they are much more prevalent than they are.
The article is worth a read and discusses the Big Cat Initiative, which is funding large conservation projects to save lions.