That's why we can not have nice things.
According to a new study, most of Earth's largest mammals have long been extinct, and humans are to blame.
Huge mammoths, elephant-sized sloths and 250-pound beavers use the earth between 2.6 million and 12,000 years. They are all extinct now.
"Species that died out were usually two to three times larger than mammals that survived, a trend that was globally evident," the study said. The results were published in Science.
Earlier research suggested that this phenomenon, known as extinction, began in Australia about 35,000 years ago. But newly discovered fossil and rock records estimate that extinction in Africa began at least 1
"It was not until human influences became a factor that large mammals made them more susceptible to extinction," said Kate Lyons, a co-author the study said in a press release.
Recent records indicate that Homo sapiens emerged as a species about 200,000 years ago. "So, not so long after the birth of us as a species, it just seems to be something we do," Lyons said.
The study finds that African mammals, when extinction began in Africa, were already 50 percent smaller than those on other continents. As humans began to migrate out of Africa, extinction in other regions of the world began to increase in size, in places consistent with popular migration patterns.
In addition, the study found that both large and small mammals are vulnerable to temperature changes during this time – which means that climate change was not a factor in the extinction of these colossal animals.
"From the point of view of the story of life, it makes some sense that if you kill a rabbit, you will feed your family for one night," said Felisa Smith, lead author of the study. "If you can kill a large mammal, you will feed your village."