By Kevin Elston
http://stream.publicbroadcasting.net/production/mp3/knau/local-knau-589512.mp3
Flagstaff, AZ – Some of the Earth's most ancient creatures have been discovered deep in caves. They have survived there for centuries, protected from climate changes on the surface. Now a team of scientists from the USGS, Northern Arizona University, and NASA are trying to find out if caves on other planets could provide a similar refuge. Arizona Public Radio's Kevin Elston reports.