Proponents of the idea that an exploding comet wiped out mammoths, giant sloths, and other megafauna 12,900 years ago have pointed to unusual organic debris in the soil from this period—debris, they say, that could have formed only in extreme wildfires raging across North America. But in a new study, a team argues that this debris is just fungal remains and bug poop.

To read the rest of the article, click here.