Freya, a massive walrus, drew crowds of delighted onlookers when she strayed into the Oslo fjord in Norway this summer. But those crowds ignored warnings to stay away, and this week authorities euthanized Freya over safety concerns. We talk to Rune Aae, who teaches biology at the University of Southeastern Norway; Martin Haulena, head veterinarian at the Vancouver Aquarium; and Boris Worm, a professor of marine conservation biology at Dalhousie University.