Ice Age Mammals of the San Pedro River Valley, Southeastern Arizona

If you had been in Southeastern Arizona eleven or twelve thousand years ago, it would look much different from today. The climate was cooler and wetter, and the rivers actually flowed. Also, you would encounter a suite of large mammals which became extinct in North America. These animals included horses, camels, mastodons, mammoths, long-horned bison, tapirs, shrub oxen, and ground sloths, which were preyed upon by dire wolves, jaguars, cougars, bears, the American lion, and man. (Horses and camels were re-introduced from Europe and Asia.)

We know this because remains of all these animals were found in several sites along the San Pedro River between Tombstone and Bisbee and at other sites in southern Arizona.

At the end of the last glacial epoch, climate became very unstable with the result that many of these megafauna became extinct in North America and the human Clovis culture dispersed. I go into greater detail on extinction hypotheses in my article “Cold case: What Killed the Mammoths?” linked below.

The Arizona Geological Survey published a paper about these animals in 1998 which has recently become available for free download:

Within this 32-page publication are drawings and brief descriptions of the animals and information about Clovis culture humans who hunted them. The paper describes how people hunted and speculates on causes of extinction.

According to AZGS:

Popular literature and illustrations often depict Clovis hunters using stone-tipped spears to attack full-grown mammoth. Archaeological evidence indicates, however, that they more often concentrated their efforts on calves and young adults, sometimes ambushing them near or at watering places. At the Lehner Mammoth Site bones of nine mammoths, all juveniles, were recovered. They were apparently trapped and killed in the stream bed where archaeologists uncovered their bones thousands of years later. The mammoth killed at the Naco Site was also a young adult.

Bison meat appears to have been popular among the Clovis people. At Murray Springs bones of eleven young bison were found along with bones of one mammoth. Both the mammoth and the bison were likely ambushed when they came to water.

Being so large and cumbersome to transport, a mammoth carcass was butchered where it fell. The presence of hearths at kill sites, such as Murray Springs and the Lehner Site, suggests that the hunters also ate some of the meat on the spot, perhaps roasting it as they proceeded with the butchering. Cut marks on bone surfaces, and broken cutting tools indicate that the meat was stripped from the carcass and transported to a nearby camp, where more of it could have been eaten or dried for future consumption.

See also:

Cold Case: What Killed the Mammoths?

A Very Brief History of Climate Change in the Sonoran Desert

Where the Glyptodonts roamed