Why did the elephants leave?

A herd of 15 wild elephants in southwest China have become social media stars as they trek through forests, farmland and a bustling city hundreds of miles from their home. Many people have been asking where the elephants are headed, but professor Joshua Plotnik says the more important question for scientists is why did they leave? Plotnik, an expert on Asian elephant cognition and behavior at Hunter College in New York, shared his observations with the CBC’s “As It Happens.”