Humankind probably exterminated Earth's megafauna 13,000 years ago: how it happened
Mankind is most likely directly related to the extinction of megafauna species that occurred at the end of the last ice age about 13,000 years ago. Scientists believe that the giant animals died, in part, because of human activity that led to large-scale fires during the dry and hot period.
This conclusion was reached by researchers who studied fossilized remains in the La Brea tar pit in Southern California (USA). As IFL Science writes, they are concerned about their discovery, given the growing number of forest fires in many parts of America and Europe against the background of global warming.
About two-thirds of large mammals outside Africa disappeared about 13,000 years ago at the end of the last ice age. It was the greatest extinction since the impact of an asteroid on Earth wiped out all the great dinosaurs.
This mass extinction coincided with climate change and the emergence of new colonies. But scientists were still unsure of exactly what factor caused this extinction because they lacked reliably dated fossils and an accurate chronology.
"The problem was that no one could pinpoint exactly when most of these large mammals went extinct because the fossil record is very inconsistent. It's hard to say much about what led to the extinction if you don't know when it happened," said Dr. Emily Lindsey, co-author of the study, which was published in Nature, associate curator and director of the La Brea excavation.
To overcome this problem, Lindsey and her colleagues analyzed fossils from the La Brea tar pit that belonged to eight large mammal species, including coyotes, horses, saber-toothed cats, the American lion, ferocious wolves and the ancient camel Camelops hesternus. Radiocarbon analysis showed that seven of these species became extinct about 13,000 years ago.
The La Brea tar pits are useful to scientists because the remains it holds are invaluable for scientific research. By comparing them to data on climate, pollen and fire in the area, as well as data on human population movement and growth, researchers have been able to rule out some of the competing explanations for the mass extinction.
"The moment we found that the North American population started to grow, we see an interval of profound climatic and ecological change combined with an unprecedented fire occurring right here, and it's in that interval that all the megafauna species disappear," said UCLA graduate student Lisa Martinez, who was a participant in the study.
The scientists' work set up a chain of links whereby a warming climate, a decrease in tree pollen and an increase in human population led to the decline of large herbivores. According to their analysis, the loss of tree pollen also indicates an increase in fires, a significant number of which have been linked to human activity.
"With the arrival of humans, we see significant changes in the frequency and intensity of fires," said Dr. Regan Dunn, paleobotanist and assistant curator of the La Brea tar pits.
She added that 95 percent of the fires we see today are caused by anthropogenic sources: power lines, campfires, highways, cigarettes or something similar.
"We somewhat already know what happened, and what we have learned from the past can help us understand what will happen in the future and how best to plan to avoid ecosystem collapses," she said.
Scientists warn that humanity is now caught in the same chain of events that led to the last mass extinction, and therefore it is important to pay attention to the warning from the past.
Earlier OBOZREVATEL spoke about what entailed the complete extermination of the first people in Europe.