Hypercarnivores, or enormous predators, most likely shaped the ecosystem during the Pleistocene epoch, researchers revealed in a new study. Essentially, packs of these large animals controlled populations of herbivores and, as a result, preserved the ancient landscapes and valuable vegetation.

During the Pleistocene, about 1 million to 11,000 years ago, herbivores such as the Columbian mammoth, mastodons and giant ground sloths could be seen grazing throughout various areas, according to a news release. While these landscapes were home to many species of megafauna, researchers from Duke University were curious as to how the large ancient herbivores didn't run out of vegetation or turn the Pleistocene into a dry wasteland. 

It turns out that gigantic carnivorous predators were able to keep herbivore populations in check. This would have ensured that there was plenty of vegetation to go around and certainly enough plump, nutrient-rich herbivores for the hypercarnviores to feed on, the researchers noted in the study.

For their study, researchers used genetic information preserved in fossil teeth to develop mathematical formulae that allowed them to estimate how large carnivorous predators would have been compared to the herbivorous prey. Using these estimates, researchers concluded that hypercarnivores would have been about twice as large as modern wolves, lions and hyenas we see today.

This means that the largest ancient cave hyena alone could have taken down a five-year-old juvenile mastodon weighing more than a ton, according to researchers. However, the animals were much more powerful as a team. Researchers estimated that a hyena pack could have easily captured a nine-year-old mastodon weighing two tons.

"Based on observations of living mega-herbivores, such as elephants, rhinos, giraffes and hippos, scientists have generally thought that these species were largely immune to predation, mainly because of their large size as adults and strong maternal protection of very young offspring," Blaire Van Vlkenburgh, a  paleoecologist from the University of California, Los Angeles, and one of the study researchers, said in a statement. "Data on modern lion kills of elephants indicates that larger prides are more successful and we argue that Pleistocene carnivore species probably formed larger prides and packs than are typically observed today--making it easier for them to attack and kill fairly large juveniles and young adult mega-herbivores."

Before humans started hunting, populations of big cats and wolves were much larger, meaning they were able to travel in large packs and hunt more efficiently, Van Valkenburgh added. Understanding these predator-prey relationships before humans were added to the mix is essential to properly guiding conservation efforts of natural habitats today.  

"You can't just make assumptions based on what we see today. The best way to understand community dynamics absent human influences is to look to the natural experiments in the fossil record," V. Louise Roth, a biologist from Duke University, said in the release.  

Their study, recently published in the Proceedings of the National Academy of Sciences, sheds light on the diversified roles ancient animals had in the Pleistocene ecosystem.  

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