Final answer:
The extinction of American megafauna took place after humans, including the Clovis people, arrived in the Americas around 10,000-12,000 years ago. Evidence suggests that overhunting by humans plays a significant role, although climate changes are also considered a contributing factor.
Step-by-step explanation:
The mass extinction of American megafauna occurred after humans arrived in the Americas, roughly 10,000-12,000 years ago. This extinction included mammals such as woolly mammoths, mastodons, and giant beavers. The arrival of humans, equipped with efficient hunting techniques, coincides with a spike in extinctions, suggesting that overhunting by the Clovis people likely played a significant role. However, some researchers also consider rapid climate changes during the Pleistocene epoch as a contributing factor. Studies indicate that in about one-third of the cases, the data shows a clear overlap between human arrival and species extinction. Although the debate continues, it is widely recognized that human activity had a considerable impact on these extinctions, with climate change potentially exacerbating the situation.