It's official: Cats are better than dogs. Better predators, that is. So say researchers in the Proceedings of the National Academy of Sciences after looking at more than 2,000 fossils of prehistoric cats and dogs in North America.

It turns out that when cats arrived on the continent 20 million years ago, which was about 20 million years after prehistoric canines started to call it home, cats were more successful hunters and helped cause the extinction of 40 species of canines vying for the same foods, reports the Telegraph.

"We usually expect climate changes to play an overwhelming role in the evolution of biodiversity. Instead, competition among different carnivore species proved to be even more important for canids," writes the lead researcher.

"These results imply that competition among entire clades, generally considered a rare process, can play a more substantial role than climate change and body size evolution in determining the sequential rise and decline of clades," the researchers write.

In fact, the canine species that survived that competition are the early ancestors of those alive today, including wolves, foxes, jackals, and of course dogs, reports Mashable.

What's more, unlike the calamitous effect cats had on dogs, prehistoric canines had little discernible impact on the course of cat species. (See what the world's oldest cat enjoyed on his 26th birthday recently.)

This article originally appeared on Newser: In Cats vs. Dogs, History Answers

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