An Ice Age long horned giant bison fossil discovered in 2013 just east of I-15 and north of SR76, tells us a lot about what the area around today’s Fallbrook must have looked like during the last Ice Age. Paleontologists at the San Diego Natural History Museum at Balboa Park said the fossilized bones of the Fallbrook discovery, are likely Bison latifrons, and may have rested there for almost 200,000 years. This is the first Bison latifrons found in southern California outside of the La Brea Tar Pits.
The long horned giant North American bison was an herbivore that grazed small trees and shrubs at eye-level.[1] Different from modern buffalo, these long-horned bison were larger and more solitaire. They made their homes in forests and woodland clearings, living in small groups.[2] Temperate open woodland was covering most of the American southwest about 15,000 years ago[3].
During the Pleistocene Ice Age, southern California was cooler than today, but temperatures here remained above freezing as the Ice sheets did not come this far south. Glacier-type conditions did exist on the peaks on the surrounding mountains of the area which had emerged by this time.[4] Bison latifrons became extinct about 30,000 years ago. The skull of the Fallbrook fossil was found a short distance away from other parts of the body, suggesting that the animal had been scavenged by other beasts.[5]
A well-known predator of the bison is the saber tooth tiger (Smilodon californicus) that roamed Southern California at this time. This Ice Age cat is the official California State fossil. More than 160,000 fossil bones of the saber tooth tiger have been found in the Los Angeles La Brea Tar Pits. Although Saber tooth cat fossils have not yet been found around Fallbrook, there could be a buried fossil still out there waiting for the next highway project to dig it up. Southern California forests in the Ice Age were ideal for saber tooth tiger hunting methods. Recent research[6] provides evidence that the saber tooth cat hunted within forested ecosystems using leafy cover to potentially ambush their prey, as cats typically do. The Saber Tooth tiger became extinct over 10,000 years ago.[7]
Another widespread predator roaming the southern California Ige Age ecosystem was the Dire Wolf (Canus dirus). The Dire Wolf had a wide range in Ice Age southern California. More than 3,600 Dire Wolf individuals have also been recovered from the La Brea Tar Pits in Los Angeles, plus a Dire Wolf skeleton has been found in National City, near San Diego. A wolf probably could not kill a giant bison by itself, indicating that Dire Wolves probably did not typically compete with the cats for bison. The wolves preferred hunting method was to chase their herbivore prey, such as deer and wild horses. However, a Dire wolf pack could bring down a large bison with multiple bites. One paleontologist described them as a pack of running jaws. The Dire Wolf became extinct more than 10,000 years ago.[8]
Tom Frew,
FHS Historian
Footnotes:
[1.] San Diego Zoo Wildlife Alliance, ‘long-horned Bison fact sheet,’ 2009. [accessed 2021 04].
[2.] Western Digs magazine, ‘Giant Ice-Age ‘Longhorn Bison’ Unearthed in San Diego’ Blake De Pastino, May 13, 2013.
[3.] Environmental Science Division, Oak Ridge National Lab; https://www.esd.ornl.gov/projects/qen/nercNORTHAMERICA.html
[4.] California Geology, THE PLEISTOCENE EPOCH, July/August 2001 by Natural History Museum of La Brea Tar Pits.
[5.] San Diego Natural History Museum, May 13th, 2013 reported by CNS news.
[6.] Current Biology, August 2019; Larisa DeSantis, paleontologist, Vanderbilt University.
[7.] University of Berkley Museum of Paleontology ucmp.berkley.edu
[8.] Nature, January 2021; ‘The Mysterious Extinction of the Dire Wolf’ Ben Thompson, Howe, Baker & Dolgin.
