section_path: Adaptation/Prey
section_name: Prey
paragraph_text: Prey
  
  A range of animal and plant specimens that became entrapped and were then preserved in tar pits have been removed and studied so that researchers can learn about the past. The Rancho La Brea tar pits located near Los Angeles in Southern California are a collection of pits of sticky asphalt deposits that differ in deposition time from 40,000 to 12,000 YBP. Commencing 40,000 YBP, trapped asphalt has been moved through fissures to the surface by methane pressure, forming seeps that can cover several square meters and be 9–11 m (30–36 ft) deep. A large number of dire wolf fossils have been recovered from the La Brea tar pits. Over 200,000 specimens (mostly fragments) have been recovered from the tar pits, with the remains ranging from Smilodon to squirrels, invertebrates, and plants. The time period represented in the pits includes the Last Glacial Maximum when global temperatures were 8 °C (14 °F) lower than today, the Pleistocene–Holocene transition (Bølling-Allerød interval), the Oldest Dryas cooling, the Younger Dryas cooling from 12,800 to 11,500 YBP, and the American megafaunal extinction event 12,700 YBP when 90 genera of mammals weighing over 44 kg (97 lb) became extinct.
  
  Isotope analysis can be used to identify some chemical elements, allowing researchers to make inferences about the diet of the species found in the pits. Isotope analysis of bone collagen extracted from La Brea specimens provides evidence that the dire wolf, Smilodon, and the American lion (Panthera atrox) competed for the same prey. Their prey probably included the extinct camel Camelops hesternus, the extinct bison Bison antiquus, the "dwarf" pronghorn (Capromeryx minor), the equine Equus occidentalis, and Harlan's ground sloth (Paramylodon harlani) native to North American grasslands. The Columbian mammoth (Mammuthus columbi) and the American mastodon (Mammut americanum) were rare at La Brea. The horses remained mixed feeders and the pronghorns mixed browsers, but at the Last Glacial Maximum and its associated shift in vegetation the camels and bison were forced to rely more heavily on conifers. A similar later isotope study of Rancho La Brea dire wolves in 2020 found a similar result, suggesting that they primarily fed on juvenile bison and camels, to a lesser extent on Harlan's ground sloth. In Peccary Cave in the Ozark Mountains of Arkansas, the primary prey were likely flat-headed peccary (Platygonus compressus). This indicates that the dire wolf was not a prey specialist, and at the close of the Late Pleistocene before its extinction it was hunting or scavenging the most available herbivores. A study based on specimens found in Cedral, San Luis Potosí found that the dire wolf primarily preyed on herbivores that consumed C4 plants and on mixed-diet herbivores.
  
  Dire wolves likely scavenged on American mastodon and ground sloth carcasses.