Ancient canines shifted from ambushing their prey to running for it because the climate turned their woodland habitats into wide open spaces, said Christine Janis, a professor of ecology and evolutionary biology at Brown University in Providence, Rhode Island, who co-wrote a paper on the development released last month. When canines became adept at running down their four-legged food, they also became pack animals that learned to cooperate and follow their leaders.

“It does emphasize the importance of climate and how sensitive aspects of mammal evolution are to climate change,” Janis said.

Borja Figueirido, a professor at Universidad de Malaga in Spain, was the lead author of the paper Janis worked on, published in Nature Communications.

The researchers studied how the fossilized elbow joints of dogs changed over time. The animals’ legs evolved from a structure that allowed for grabbing their prey the way a cat does to one more adept at running, said Janis, now on a fellowship at the University of Bristol in the U.K.