At the end of the Pleistocene, a mystery occurred: large mammals disappeared in North America while surviving in other parts of the world. Scientists studying the late Pleistocene extinction have provided a multitude of explanations, including human overexploitation, extraterrestrial events, and climate change (Faith and Surovell, 2009). However, there was no unified explanation that they all agreed on. Taking note of this, J. Tyler Faith and Todd A. Surovell conducted tests to discover whether extinction was a single event or a long-term process. Their findings were important to other scientists in the same field because they served as a guideline for their explanations of the catalysts for extinction. Scientists in this field have mainly focused on the potential causes of this event. The first is the overkill hypothesis. In 2002, Grayson and Meltzer revisited Paul Martin's late Pleistocene extinction hypothesis, developed 40 years ago. The hypothesis states that the Late Pleistocene extinction of animals was the result of human overexploitation; Grayson and Meltzer criticize this hypothesis because Martin used evidence specific to New Zealand, where humans hunted mammals to extinction 900 years ago. Although they did not rule out human overkill during the Pleistocene extinctions, they speculated that other events could have contributed to the extinction (Grayson and Meltzer, 2003). Other scientists like Alroy have disputed this contradiction. Alroy used a computer simulation to compare changes in human population size and changes in herbivore population sizes during the late Pleistocene to support the hypothesis of overexploitation (Alroy, 2001 ). Meanwhile, Haynes used "black mats", or or...... middle of paper ......es 1675-1680, ISSN 0277-3791, 10.1016/j.quascirev.2011.03.011 .Grayson, Donald K and Meltzer, David J. A Requiem for North American Overpower, Journal of Archaeological Science, Volume 30, Number 5, May 2003, Pages 585-593, ISSN 0305-4403, 10.1016/S0305-4403( 02)00205-4. Haynes, CV Jr. Younger Dryas “black carpets” and Rancholabrian termination in North America Proceedings of the National Academy of Sciences of the United States of America 2008 105 (18) 6520-6525 Kennett, DJ; Kennett, JP; West, A; Mercer, C.; Hi, SS Que; Bement, L.; Bunch, T.E.; Sellers, M.; Wolbach, WS “Nanodiamonds in the Younger Dryas Boundary Sediment Layer” Science January 2, 2009: 323 (5910), 94. Long, CA and Yahnke, CJ “Late Pleistocene: elk-moose (Cervalces) and caribou (Rangifer) in the Wisconsin.” Mammal Journal 92(5):1127-1135. 2011