section_path: Extinction
section_name: Extinction
paragraph_text: Extinction
  
  During the Quaternary extinction event around 12,700 YBP, 90 genera of mammals weighing over 44 kilograms (97 lb) became extinct. The extinction of the large carnivores and scavengers is thought to have been caused by the extinction of the megaherbivore prey upon which they depended. The cause of the extinction of the megafauna themselves is debated but has been attributed to the impact of climatic change, competition with other species including overexploitation by newly arrived human hunters, or a combination of both. One study proposes that several extinction models should be investigated because so little is known about the biogeography of the dire wolf and its potential competitors and prey, nor how all these species interacted and responded to the environmental changes that occurred at the time of extinction.
  
  Ancient DNA and radiocarbon data indicate that local genetic populations were replaced by others within the same species or by others within the same genus. Both the dire wolf and the Beringian wolf went extinct in North America, leaving only the less carnivorous and more gracile form of the wolf to thrive, which may have outcompeted the dire wolf. One study proposes an early origin of the dire wolf lineage in the Americas which led to its reproductive isolation, such that when coyotes, dholes, gray wolves, and Xenocyon expanded into North America from Eurasia in the Late Pleistocene there could be no admixture with the dire wolf. Gray wolves and coyotes may have survived due to their ability to hybridize with other canids – such as the domestic dog – to acquire traits that resist diseases brought by taxa arriving from Eurasia. Reproductive isolation may have prevented the dire wolf from acquiring these traits. A 2023 study documented a high degree of subchondral defects in joint surfaces of dire wolf and Smilodon specimens from the La Brea Tar pits that resembled osteochondrosis dissecans. As modern dogs with this disease are inbred, the researchers suggested this would have been the case for the prehistoric species as well as they approached extinction, but cautioned that more research was needed to determine if this was also the case in specimens from other parts of the Americas.
  
  In 2019 the youngest known specimen of the 35 dire wolf fossils collected from Rancho La Brea, California was dated at 11,413 ± 754 calibrated years before present (YBP), while in 2022 the bone collagen of a dire wolf also known from Rancho La Brea, California was dated at 11,581 ± 3,768 calibrated YBP. The youngest uncalibrated geological ages assigned to dire wolf remains are dated at 9,440 YBP at Brynjulfson Cave, Boone County, Missouri, 9,860 YBP at Rancho La Brea, California, and 10,690 YBP at La Mirada, California. Some remains have been radiocarbon dated (uncalibrated) to 8,200 YBP from Whitewater Draw in Arizona, though one author has stated that radiocarbon dating of bone carbonate is unreliable. In South America, the most recent remains at Talara, Peru date to 9,030 ± 240 YBP (also uncalibrated), while the most recent remains of " C. nehringi " from Luján, Argentina are older than the most recent stratigraphical section of the site, dated to 10–11,000 YBP.