November 22, 2024

Taylor Daily Press

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Many large mammals have become extinct. Scientists finally know why.

Many large mammals have become extinct. Scientists finally know why.

Many large mammals have disappeared from the face of the Earth in the past 50,000 years. The largest animals in particular have died out en masse. Was it because of climate change or because of us? Scientists have been talking about this for decades, but now it seems that there is finally clarity.

At least 161 large mammals – those weighing at least 45 kilograms – have gone extinct in the past 50,000 years. The largest are the hardest hit. Of the 57 species of terrestrial herbivores weighing more than 1,000 kilograms, only 11 remain. That’s not going well, either.

End of discussion
There has long been a debate in science about the cause: climate change or humans. Researchers from Aarhus University now conclude A broad general study Most species have already disappeared due to direct human action. They compared the animals’ extinction periods, diets, climate and habitat requirements, previous population estimates, and evidence of human hunting. They also looked at climate and vegetation history, animal evolution, and archaeological data on human expansion and lifestyle.

The severe climate change during the last ice age between 130,000 and 11,000 years ago certainly affected the population size and distribution of animal species. However, most of them did not become extinct. This happened only with large animals. Moreover, previous ice ages did not lead to selective extinction of large animals in the past millions of years.

Excellent hunters
“The large, selective loss of megafauna in the last 50,000 years is unique in the last 66 million years. Previous episodes of climate change did not lead to large selective extinctions, suggesting that climate may not play a major role in megafauna extinctions at all,” says Professor Jens Christian Svenning. “Another major argument against climate change is that recent species extinctions have occurred at the same rate in climatically stable regions as in unstable ones.”

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So what? We humans are hunters, and we’ve been pretty good at it for a long time. Archaeologists have discovered traps designed for very large animals. Human bones and spear points also show that we’ve long been hunting the largest mammals on Earth and then roasting them over fires.

Megafauna are at risk.
“Early modern humans were efficient hunters, hunting even the largest species,” Svenning adds. “They were clearly able to reduce the numbers of large animals. These large animals were particularly vulnerable because they were pregnant for long periods, produced very few offspring at a time and took many years to reach sexual maturity.

The analysis shows that hunting of large animals such as mammoths, mastodons, and giant sloths was widespread and consistent across the globe. It also appears that these species went extinct at very different times and at different rates around the world. In some areas it happened very quickly, while in others it took more than 10,000 years. But everywhere it happened after the arrival of modern humans, or in the case of Africa, after the cultural advances of humans.

Take advantage of the warm-up process.
Species have gone extinct on every continent except Antarctica and in all types of ecosystems, from tropical rainforests and savannas to temperate forests and steppes. “Many extinct species can thrive in all types of places. Therefore, their extinction cannot be explained by climate change, which, for example, caused the disappearance of a particular ecosystem, such as the mammoth steppe.” “Most species lived in temperate to tropical conditions and would have benefited from the warming at the end of the last ice age.”

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Yet man with his spears, bows and arrows, guns and traps. And this was not without consequences. Large animals play a central role in ecosystems by affecting forest density and the openness of other natural areas, as well as seed dispersal and nutrient cycling. Their extinction has led to major changes in ecosystems around the world.

Large Animal Recovery
“Our results underscore the need to work to restore and preserve animal species and the nature they inhabit,” says Svenning. “By reintroducing large mammals, we can help restore ecological balance and increase biodiversity.” So we need to quickly become more careful with all those beautiful big animals that the Earth has to offer.