Early Dogs drove to Extinction by the Cats

The dogs family originated in North America 40 Million of years ago and reached a maximum diversity around 22 million of years ago, when more than 30 species inhabited the continent. Today only 9 species of them lived in North America. They progressively increased in body size and species and specialized into becoming large predator. Some of them exceeded 30 kg and were among the largest carnivore on the North American continent. Although there are several large carnivores today face a higher extinction risk than smaller species, the author of the study found no evidence of a similar pattern in ancient canid species.

In the ancient times in the North America the canid species and the felid species fights for the same food just what we see in the Africa today where lions, leopards, Hyenas, wild dogs and other carnivores. New researches revealed that the ancient felids have strong negative impacts on the survivals of the ancient dogs but the opposite is not true. 

This also proved that the ancient felid species are much more efficient hunters than the ancient dogs.

Source: University of Gothenberg