It was a bigger, meaner, more ferocious world a millions of years ago — and new computer models show just how vicious it was thanks to super-predators.

It has always been a question for scientists: how would these cave hyenas and saber-toothed tigers tackle such incredibly huge beasts like mammoths, mastodons, and giants sloths? Now, they think they know, according to a Live Science report.

Taking down a mastodon is no small task: they can weigh an astonishing two tons, and even a young mastodon would weigh more than a ton. But, as they say, life finds a way, and the new computer models show just how.

These super-predators were much bigger than the wolves and lions of today, which they needed to be in order to handle such big prey. Their existence helped keep the populations of these giant herbivores in check, lead author Blaire Van Valkenburgh of the University of California Los Angeles said according to the report.

It’s a good thing these super-predators were around to keep the herbivores from running rampant. We may not think of herbivores as much of a threat, but in reality they an devastating ecosystems when left unchecked. We can see this today when elephants and white-tailed deer run rampant in areas and strip them of vegetation. Overgrazing is very destructive for habitats, and the super-predators of that era kept that from happening between 1 million and 11,000 years ago — perhaps helping humankind in the process as we evolved into the species we are today.

The world has certainly changed today. Now, large herbivores like elephants have little to fear from predators. But that wasn’t the case a million years ago when hypercarnivores preyed on huge herbivores in what were likely epic battles for survival.

In fact, there were probably much more predators back then — or at least a greater diversity — than there are today, perhaps because intense competition forced some predators to evolve to specialize in hunting huge prey.