why humans might be to blame

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Come with us on a journey to discover the incredible megafauna of the Pleistocene epoch and learn about some of the most plausible theories and explanations.

What was the megafauna?

More accurately called the Pleistocene megafauna, these were a group of huge animals that inhabited the Earth throughout the Pleistocene period (about 2.5 million to 11,700 years ago).

This last date, 11,700, corresponds to an event known as Younger Dryas, which we will discuss in more detail later.

An iconic artistic representation of Pleistocene megafauna.

During the Quaternary extinction event, many Pleistocene megafauna became extinct, dramatically altering ecosystems around the world. The cause is a subject of heated scientific debate, but theories range from humans to climate change being the primary causes.

The classification of a member of megafauna generally includes animals (usually mammals) that are larger than 99 pounds (45 kilograms).

The types of creatures included in this classification vary from continent to continent.

For example, Australia’s Pleistocene megafauna include the enormous Diprotodon, which resembled a giant wombat, and the massive Megalania goanna.

Some of the more notable examples that lived in Europe include mammoths, cave lions, cave bears, straight-tusked elephants, interglacial rhinoceros (Stephanorhinus), heavy-bodied Asiatic antelope (Spirocerus), hippos Eurasians, the woolly rhinoceros, the gigantic deer, the saber-toothed cat (Homotherium) and the leopard.

Of all the megafauna that ever existed, most of the remaining species are found in Africa. But what happened to the rest?

Let’s review the most popular theories.

What wiped out the megafauna?

We are not entirely sure, but the megafauna in the world has probably disappeared for ecological and environmental reasons. Whatever the cause, we have a good idea of ​​when.

Fossil evidence from many continents indicates that megafauna animals became extinct at or near the end of the last ice age. Various megafauna appear to have gone extinct at different times.

Yet the general trend over a few hundred thousand years indicates the large-scale elimination of most of the largest animals of the time.

For example, the straight-tusked elephant died out in Eurasia between 100,000 and 50,000 years ago. Between 50,000 and 16,000 years ago, Eurasian hippos, interglacial rhinos, heavy-bodied Asiatic antelopes, and cave bears (Ursus spelaeus) also became extinct.

The saber-toothed cat (Homotherium), the cave lion and the leopard disappeared from Europe 28,000, 11,900 and 27,000 years ago. Between 16,000 and 11,500 years ago, the woolly rhinoceros and the last mammoths also died out.

11,500 years ago the great deer disappeared, with the last pocket remaining in Western Siberia until about 7,700 years ago.

However, the extinction event was not total. A small mammoth population was still present on Wrangel Island 4,500 years ago.

So what happened to them?

As mentioned earlier, currently the most supported theories include the pressure of climate change and the possible impact of human hunting.

As for the former, scientists have succeeded in reconstructing the evolution of the climate throughout this period. A series of severe and rapid climatic changes, with regional temperature variations of up to 16°C, characterized the Late Pleistocene and have been linked to the extinction of large mammals.

However, megafauna extinctions during the height of the Last Glacial Maximum (LGM) do not appear to have occurred, indicating that increasing seasonality and subsequent changes in available plants were not the only cause.

While climate change seems to have been bad for large mammals, climate changes at the time could have benefited our earliest ancestors.

Around 195,000 years ago, the ancestors of modern humans first appeared in East Africa. Some left Africa around 60,000 to 90,000 years ago, with one group finally reaching Central Asia around 50,000 to 40,000 years ago.

From there, people traveled to Europe. Human remains dating from 43,000 to 45,000 years ago have been found in Italy, Britain and the European Russian Arctic.

About 27,000 years ago, another group left Central Asia and traveled to the lower reaches of the Yana River in Siberia, which lies well above the Arctic Circle. In the Central Siberian Arctic, in Yenisei Bay, remains of mammoths that humans hunted 45,000 years ago have been discovered.

Between 20,000 and 11,000 years ago, when the Wisconsin Glacier retreated, but before rising sea levels submerged the Bering Land Bridge, modern humans crossed the Bering Land Bridge and entered North America.

However, there is still disagreement among scholars about the timing of human migration to the Americas.

The first agricultural practices appeared in the Fertile Crescent 11,500 years ago.

Some believe that megafauna initially evolved in response to glacial circumstances and became extinct with the onset of warmer temperatures and the resulting changes in vegetation.

Illustration of Paleo-Indians hunting a glyptodon.

The extinction of megafauna in temperate Eurasia and North America ended simultaneously when a vast expanse of forest replaced the immense periglacial tundra in both regions. Elk, deer, and pigs, better adapted to forests, have supplanted glacial species like mammoths and woolly rhinos.

Horses moved south to the Central Asian steppes while reindeer (caribou) moved north. Even though humans just started colonizing non-tropical Eurasia and non-tropical North America less than 15,000 years ago and 10,000 years ago, respectively,

Tropical or subtropical regions have experienced less drastic climate change. The most notable of these changes was the conversion of a significant portion of North Africa into the largest desert on the planet. Africa and tropical and subtropical Asia both avoided catastrophic wildlife extinction, which allowed some of the continent’s megafauna to survive to the present day.

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