Some blue whales off the coast of California change their behaviour when exposed to the sort of underwater sounds used during
US military exercises. The whales may alter diving behaviour or temporarily avoid important feeding areas, according to a study published in the Proceedings of the Royal Society B. The study exposed tagged blue whales to simulated mid-frequency (3.5-4 kilohertz) sonar sounds significantly less intense than the military uses. The findings help to understand risks to these animals from human sound and inform timely conservation and management decisions.