Why did our species survive?

from By Maggie Koerth-Baker at BoingBoing:

Today, we're the only living member of the genus Homo and the only living member of the subtribe Hominina. Along with chimpanzees and bonobos, we're all that remains of the tribe Hominini.

But the fossil record tells us that wasn't always the case. There were, for instance, at least eight other species of Homo running around this planet at one time. So what happened to them? What makes us so special that we're still here? And isn't it just a little weird and meta to be fretting about this? I mean, do lions and tigers spend a lot of time pondering the fate of the Smilodon?