There are dog lovers and then there are cat lovers. However, there is a scientific proof that cats might actually be better than dogs when it comes to evolution.

A study conducted on ancient fossils has revealed that cats have been better at survival than the members of the dog family. According to a team of researchers from Sweden, Switzerland and Brazil, the felids, or wild cats moved from Asia to North America and spread rapidly. The felids took over the North American continent to such an extent that nearly 40 species of wild dogs, or canids, became totally extinct.

The study, published in the journal PNAS, further said that the extinction of the wild dog species due to cats was much more severe and deadly than the extinction facilitated by climate change. The study findings were based on an analysis of 2,000 ancient fossils.

"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," Daniele Silvestro of the University of Gothenburg, Sweden and the study's lead author, said.

Because of their effective hunting skills, the cats outcompeted the dogs for the limited food supplies. At the same time, the researchers did not find any clue suggesting that dogs wiped out even a single species of the wild cats.

The felids arrived in North America when the dog population was at its peak -- nearly 30 species around 20 million years ago. The dogs had been surviving on the continent since their origin, which took place around 40 million years ago. The arrival of the cats marked the occurrence of a deadly impact on the dog population, with only nine species left on the continent.

The researchers are unsure about the actual conditions that had let the cats wipe out dogs so comprehensively. However, the team believes that the ancient felids had retractable claws, which they have passed on to what are known as domestic cats today. Dogs, on the other hand, did not have such claws.

“Felids must have been more efficient predators than most of the extinct species in the dog family,” the researchers said in the report.