Packrat Middens Give Clues to Ancient Climate
By George Zamora

Two New Mexico Tech geoscientists and their research colleagues are analyzing ancient packrat middens?globs of crystallized packrat urine containing twigs, leaves, seeds, and other debris which the scavenging rodents drag into their nests?to draw up more accurate production and deposition histories of naturally occurring radioisotopes over the past 40,000 years. View Entire Article »