With noise pollution in the world's oceans doubling every decade by some estimates, whales are apparently having trouble hearing one another. Researchers studying right whales found that they have to raise their voices—or "increase the amplitude of their calls," in more scientific language—as background noise from shipping gets louder, LiveScience reports.
Up to a certain level, the whales can adjust. But the louder calls take more energy and run the risk of relaying garbled messages. They also give a head's up to nearby predators. "The impacts of increases in ocean noise from human activities are a concern for the conservation of marine animals like right whales," says the lead researcher from Penn State.
(Read more whales stories.)