Anne Blair Gould goes on location to talk to Dutch researchers who are testing the hearing abilities of dolphins and porpoises. This information should result in an alarm system that would warn dolphins and porpoises to stay clear of fishing nets. Each year, hundreds of thousands of these mammals drown after being caught in huge nets. In the Arctic, walruses are being scared off breeding by oil drilling and shipping. So what do they hear?
Producer: Anne Blair Gould