well, about 90% of the world's species are extinct... and it all had to do with nature (you can say natural selection).

really, it's nothing past normal for animals to be threatened. and since man has increased population by a shitload over a small amount of times (a few hundred years), we are taking up more space, eating more animals, and consuming more resources. but that is a grain of salt compared to how nature takes effect.

animals have been dying out due to nature since the birth of Earth.

I think that the reason so many animals are going extinct is because they go so well with mash potatoes and gravy ;)