The hierarchy in a group of dogs is not based on aggression but on submissiveness. A dog ranked lower in the hierarchy displays signals of submissive behavior towards dogs ranked higher. These findings have for the first time been substantiated by means of measurements.
A cooling, drying climate over the last 40 million years turned North America from a warm and wooded place into the drier, open plains we know today. A new study shows how dogs evolved in response to those changes, demonstrating that predators are sensitive to climate change because it alters the hunting opportunities in their habitat.