GREEN
03/18/2010 05:12 am ET Updated May 25, 2011

Dung Helps Reveal Why Mammoths Died Out

Their results showed a slow decline in megafauna that began about 15,000 years ago and appeared to last for about 1,000 years.

This discovery rules out one idea that the extinction might have been caused by an extraterrestrial object striking Earth 13,000 years ago.

Read more on BBC News