The Arizona Geological Survey has just made available an interesting booklet: “Ice Age Mammals of the San Pedro River Valley, Southeastern Arizona.”
“As recently as 11 ,000 years ago the broad plains of the San Pedro River Valley teemed with herds of horse, camel, mastodon, mammoth, and long-horned bison. They, along with tapir and ground sloth, were preyed upon by dire wolf, jaguar, cougar, bear, and man. Most of these large Ice Age (Pleistocene) mammals, collectively called megafauna by scientists, are extinct.
The Clovis people (Paleo-Indians), big game hunters who followed the herds, are also gone–replaced by a succession of cultures that were dependent on small game, the gathering of seeds and nuts, and, later, agriculture. Today, just a few feet below the ground in the San Pedro Valley, the fossil remains of these large animals, together with associated plant pollen and Paleo-Indian artifacts, provide one of the most complete records of Pleistocene mammals, vegetation change, and early man in North America.”
This booklet was originally published in 1998 and is now available for free download (33Mb).
http://repository.azgs.az.gov/sites/default/files/dlio/files/nid1682/dte-06_ice_age_mammals-ocr.pdf
Take a look and see how southern Arizona was much different in the past.