大象传媒

Four million years ago, dogs had a lucky break. The world's climate was becoming drier and trees were being replaced by vast plains of grassland and scrubland. A new sort of fleet-footed prey then evolved to occupy them. But why should these events have helped the dogs rather than the cats? The big cats of 4 million years ago lost the cover they needed for ambush. They had a short burst of speed but in a straight chase they didn't have the stamina to keep up with their speedy prey. Dogs, on the other hand, had long legs, speed and stamina. They could hunt down the new, fast prey as a running pack. A team of fast-running, social hunters, the African wild dog pack became a social unit. The way they kill may seem brutal but it's efficient and evolution rewards efficiency. Several species of running pack hunter spread across the globe and as recently as 1,000 years ago, the wild dog covered the plains of Africa while the red dog ranged across much of Asia. The grey wolf however covered the entire northern hemisphere, making it the most widspread hunter on the globe.