EXTINCTIONS

The Megafauna Extinction

~50,000 to 4,000 years ago

Phanerozoic · Cenozoic · Quaternary · Pleistocene · Late Pleistocene

Mammoths, giant ground sloths, marsupial lions and most other large land animals disappeared, continent by continent, each shortly after people arrived: Australia around forty-five thousand years ago, the Americas near thirteen thousand, with island survivors such as the Wrangel Island mammoths lasting until four thousand. A global analysis of every large mammal lost worldwide ties the severity of the losses to where hominins had been, with at most a weak link to climate, and that only in Eurasia.

Why it matters

In this wave of extinctions, our species is the leading suspect for the first time. It is also why the world we take for natural is missing its largest animals: every continent except Africa lost most of what was big, and we have grown up calling the remainder normal.

Dating & uncertainty

Losses are staggered by continent and follow the arrival of people: Australia by about 45 ka, the Americas near 13 ka, with island populations such as the Wrangel Island mammoths surviving to about 4 ka. The quality of the dating varies a great deal from one region to the next, and how much weight to give hunting against climate is still argued.

Sources

1. Sandom et al. (2014), Proceedings of the Royal Society B · Global late Quaternary megafauna extinctions linked to humans, not climate change
2. Lorenzen et al. (2011), Nature · Species-specific responses of Late Quaternary megafauna to climate and humans
3. Smith et al. (2018), Science · Body size downgrading of mammals over the late Quaternary
4. Stuart (2014), Geological Journal · Late Quaternary megafaunal extinctions on the continents: a short review

Earth history as one day

23:59:59.05952 ms before midnight

if Earth’s 4.54 billion years were compressed into a single day