London, Aug 13 (IANS): Competition played a far greater role in the evolution of the dog species than climate change, a study revealed.

Based on the analysis of over 2000 fossils, the study found that the arrival of the cats (Felidae), in North America from Asia had a deadly impact on the diversity of the dog family (canidae), contributing to the extinction of as many as 40 of their species.

"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," said lead author Daniele Silvestro from the University of Gothenburg, Sweden.

The evolutionary success of carnivorous animals is inevitably linked to their ability to obtain food.

The limited amount of resources (prey) leads to strong competition among carnivores sharing the same geographic range.

For instance African carnivores such as wild dogs, hyenas, lions and other felids are constantly competing with each other for food.

North American carnivores in the past might have followed similar dynamics and much of the competition is found among species of the dog family and from ancient felids and dogs.

Around 22 million years ago, over 30 species of the dog family inhabited North America. Today, only nine species are left on the continent.

Interestingly, while the cats appeared to have a strongly negative impact on the survival of ancient dogs, the opposite is not true.

This suggests that the cats must have been more efficient predators than most of the extinct species in the dog family.

The findings were published in the journal, PNAS.