Why did many large Pleistocene animals become extinct near the beginning of the Holocene?

The extinction of many large Pleistocene mammals, such as mammoths and mastodons, remains a subject of vigorous scientific debate. Rather than a single cause, it is widely believed that a combination of factors contributed to these megafaunal extinctions.

The two primary hypotheses are:

• Overkill Hypothesis: This theory suggests that the arrival of skilled human hunters, such as those associated with the Clovis complex, led to the rapid decline of large herbivores that were unaccustomed to human predation. As these prey populations collapsed, large carnivores were subsequently affected.123
• Climatic and Environmental Change: The transition from the Pleistocene to the Holocene Epoch involved abrupt shifts in climate, including increased seasonality and the reorganization of vegetation. These changes disrupted established habitats and food sources, placing significant stress on large species.123

Most researchers now suggest that the causes varied by geographic region and that both human activity and environmental instability played roles of differing importance in the disappearance of these animals.12