On the afternoon of February 16, 2009, a 70-year-old woman named Sandra Herold called 911 in Stamford, CT to report her 200-lb. chimp, Travis, had gone on a rampage outside her home, and was eating her friend, 55-year-old Charla Nash. The docile primate, who had been raised by humans and socialized among the public, from starring in TV commercials and print advertisements to making special appearances, had never harmed a fly.

But something changed. And Travis snapped. The question is why.

Join host Ryan Kraus for a psychological exploration of the evolutionary divide between humans and wild animals that leads to these tragedies.