Listening in on fish grunts, and more…

Scientists recorded audio and video of 8 different kinds of rockfish living in the wild near British Columbia, and were surprised they could tell the species apart through their various grunts, pops and knocks, even though the fish are closely related.PLUS:DNA identifies four Franklin Expedition sailors — and solves a 160-year-old mysteryImmune cells that fight infection get a boost from food Radio waves let us see the unseeable: black holes, pulsars and volcanoes on VenusFrom the archives: What will the Earth look like in 2050?Quirks Question: If chicken and fish blood is red, why are they white meats?