A recent study has revealed that the 40 million years old fossils of North American dog suggest that the evolution of predators may be directly affected by a change in climate, researchers at Brown University reported in a press release.

The study was published in Nature Communications.

Christine Janis, professor of ecology and evolutionary biology at Brown University said in a press release, "It is reinforcing the idea that predators may be as directly sensitive to climate and habitat as herbivores."

Christine Janis worked with lead author Borja Figueirido, a former Brown Fulbright postdoctoral researcher who is now a professor at the Universidad de Málaga in Spain.

The fossils show that the North American dogs were small mongoose like animals to begin with, with flexible forelimbs to catch whatever meal they could grab onto without running.

However, a few million years later, the dogs evolved into predators who caught their meal through running and pouncing. The clear pattern in the evolution of the dogs can be linked to the change in the global climate around that time. Also, the growth of the rocky mountains in North America made the interior much drier with the forests giving way to grasslands.

For the study, Figueirido and the research team, including Jack Tseng of the American Museum of Natural History in New York, examined the elbows and teeth of 32 species of dogs spanning the period from 40 million years ago to two million years ago.

"The elbow is a really good proxy for what carnivores are doing with their forelimbs, which tells their entire locomotion repertoire," Janis said in the press release.

The study suggests that predators do not only evolve as a response to the anatomy of their prey. Rather, the predator evolution is directly linked with the climate changes to habitat rather than to the anatomy of their preys.

The authors of the study also pointed out that if predators evolved with climate change, then they are likely to continue to evolve with the climate change that is going on now.