Geological Society of America. "New Theory For Mass Extinctions." ScienceDaily. www.sciencedaily.com / releases / 2006 / 10 / 061025085208.htm (accessed June 4, 2025). Explore More. from ScienceDaily.

The new Utah site is the third mass tyrannosaur grave site that's been discovered in North America - bolstering a theory first developed 20 years ago that they lived in packs.

A new theory on just what causes Earth's worst mass extinctions may help settle the endless scientific dust-up on the matter. Whether you favor meteor impacts, volcanic eruptions, cosmic rays ...