During the Cenozoic era, the North American Great Plains are known to have held some of the most diverse populations of mammals in history. During the era, there were two interesting mammalian families that existed at the same relative time: the Entelodontidae and the Amphicyonidae. There has been speculation that the fall of the Entelodontidae contributed to the rise of Amphicyonidae due to competition. The source of the competition has been a result of suggested reconstruction of both families having members with the same bear-like omnivore diet, and thus having to compete for the same food supply. Many of these claims have been made as a result of comparing the changes in body sizes of entelodonts to those of amphicyonids over time. Up now, these claims have only been suggestions, as no actual data has been put forth in full to support of them. Body size would be a legitimate stand in for competition because testing the diet would be a much larger task than what time would allow for at the time of project. In order to test this claim, an idea of body for entelodonts and amphicyonids must be determined and for that using the first lower molar is appropriate. In order to collect data, specimens from Nebraska, South Dakota, and Wyoming are examined and the teeth are measured, with focus on the first lower molar, and then using the information of the age of the sites to form a stronger case for the transitional concept.
Maxwell Bertsos, ’14
Sponsor: John Orcutt