Quaternary extinction event

The Quaternary period saw the extinctions of numerous predominantly larger, especially megafaunal, species, many of which occurred during the transition from the to the Holocene epoch. However, this extinction wave did not stop at the end of the Pleistocene, but continued, especially on isolated islands, in human-caused extinctions, although there is debate as to whether these should be considered separate events or part of the same event. Among the main causes hypothesized by paleontologists are natural climate change and overkill by humans, who appeared during the and migrated to many regions of the world during the and Holocene. A variant of the latter possibility is the second-order predation hypothesis, which focuses more on the indirect damage caused by overcompetition with nonhuman predators. The spread of disease is also discussed as a possible reason.

The Late Pleistocene extinction event saw the extinction of many mammals weighing more than 40 kg.

The extinctions in the Americas entailed the elimination of all the larger (over 1000 kg) mammalian species of South American origin, including those that had migrated north in the Great American Interchange. Only in North America, South America, and Australia, did the extinction occur at family taxonomic levels or higher.

There are three main hypotheses concerning the Pleistocene extinction:

There are some inconsistencies between the current available data and the prehistoric overkill hypothesis. For instance, there are ambiguities around the timing of sudden extinctions of Australian megafauna. Biologists note that comparable extinctions have not occurred in Africa and South or Southeast Asia, where the fauna evolved with hominids. Post-glacial megafaunal extinctions in Africa have been spaced over a longer interval.

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