Perhaps the megafaunas turned gay and lesbian.
At lease Noah saw it coming and found a solution.
Who here has built an arc; or would we need just some good flood insurance, like these folks had?
http://afp.google.com/article/ALeqM5if9UIMmRHGQXvC7kXfFeM6rzUr_w
A comet hits the earth, and there would be at least 40 days and nights of cyclones and hurricanes!