NOVA: "Ice Age Footprints" (Windfall Films, Argonon Productions, WGBH Educational Foundation, PBS, 2022)

by Mark Gabrish Conlan • Copyright © 2024 by Mark Gabrish Conlan • All rights reserved

My husband Charles got home from work an hour early last night (Wednesday, July 3) and that meant he had time to join me for the science show I watched right after “Changing the Menu”: “Ice Age Footprints,” a 2022 episode of NOVA that dealt with archaeological and anthropological expeditions to the White Sands region of New Mexico to uncover surviving traces of Ice Age mammals. While most of Canada and the United States were under a huge sheet of ice about 20,000 years ago, the area around White Sands was actually a fresh-water lake in and around which lived mastodons, mammoths, giant sloths and, apparently, a few humans. “Ice Age Footprints” was narrated by Kirk Johnson, himself a paleontologist who had come out to the White Sands site with a team to uncover the Ice Age footprints and determine what sorts of animals made them. This poses an obvious problem because exposing the footprints means their relatively rapid destruction from the forces of wind and erosion. So the team members were especially concerned about photographing them – though I was a bit surprised they did not make plaster casts of them as a means of preservation. Johnson was guided around the site by David Bustos of the U.S. Natural Park Service, and the two of them were exploring a site right next door to a major U.S. missile base (go figure).

The show also included an interview with Emily Lindsey, manager of the La Brea Tar Pits museum in Los Angeles. I’ve been to the La Brea Tar Pits several times and at first I was disappointed that it didn’t contain dinosaurs (the tar pits didn’t develop until millions of years after the Jurassic and Cretaceous eras in which the dinosaurs lived), though what they did have was stunning enough. One of the most interesting aspects of the show was the number of people involved in the digs who were Native Americans. Native Americans have generally regarded anthropologists as enemies because historically they’ve clung to views of America’s Native cultures as “primitive” and “uncivilized” and have perpetuated racist stereotypes about them. Among the Natives working with Johnson and Bustos on this project were Joe E. Watkins (Choctaw), Kim Charley (Pueblo), Carol Ellick and Edward Jolie. The show also included two technicians, Kathleen Springer and Jeff Pigati, from the U.S. Geological Survey, who are experts at radiocarbon-14 dating and were called in to determine just how old the footprints are. The footprints themselves were made of sand and therefore contained no organic material from which radiocarbon dating could be done. But hopefully the people (and other creatures) who made the footprints in the first place also tracked in organic materials – and it turned out they did: seeds.

Based on their dating tests (and the show featured a brief explanation of how radiocarbon-14 dating is done; it actually takes a year and a half between the time they start processing a sample and the time they can get a result), they concluded that the human footprints were between 21,000 and 23,000 years old – when the previous anthropological consensus had been that humans didn’t arrive on the Western Hemisphere until 11,000 to 13,000 years ago. The previous belief had been that they came down through a corridor on the otherwise frozen ice surface that covered western Canada and walked down from there after crossing the frozen-over Bering Strait from what is now Siberia. The new findings, which are still controversial and not fully accepted by the scientific community even though an end title said at least two more recent studies have confirmed them, suggest there were actually Native Americans well before that corridor opened up. That’s led to historic speculations about how they got there, including one theory that they actually hugged the west coasts of Canada and the U.S. in boats. Another big question is what role, if any, did the newly arrived humans play in the sudden mass extinction of the big Ice Age mammals. A number of people involved in the study deduced from the locations of the various footprints that humans might actually have been hunting the giant sloths, much the way later Native Americans hunted buffalo. Did they kill enough of them to threaten their survival as a species? Did climate change play a role? This NOVA episode was unusual among scientific TV programs in that it raised quite a few more questions than it answered, but it was well worth watching and Charles seemed to like it better than he usually likes science documentaries.