Whales flee from the loud military sonar used by navies to hunt submarines, new research has proven for the first time. The studies provide a missing link in the puzzle that has connected naval exercises around the world to unusual mass strandings of whales and dolphins. Beaked whales, the most common casualty of the strandings, were shown to be highly sensitive to sonar. But the research also revealed unexpectedly that blue whales, the largest animals on Earth and whose population has plummeted by 95% in the last century, also abandoned feeding and swam rapidly away from sonar noise. The strong response observed in the beaked whales occurred at noise levels well below those allowed for US navy exercises. For whales and dolphins, listening is as important as seeing is for humans - they communicate, locate food, and navigate using sound," said Sarah Dolman, at charity Whale and Dolphin Conservation. "Noise pollution threatens vulnerable populations, driving them away from areas important to their survival, and at worst injuring or even causing the deaths of some whales and dolphins." Dolman said there were no accepted international standards regarding noise pollution and there was an urgent need to re-evaluate the environmental impacts of military activities. Unusual mass strandings, where multiple species of whale and dolphin beach at several locations at once, have soared since the introduction of military sonar in the 1950s and can be fatal. The strandings occur every year and major recent events saw up to 15 animals beached in the Canary Islands, the Bahamas and Greece.