The songs that whales and dolphins use to communicate, orient themselves and find mates are being drowned out by human-made noises in the world's oceans, UN officials and environmental groups said Wednesday.
That sound pollution -- everything from increasing commercial shipping and seismic surveys to a new generation of military sonar -- is not only confounding the mammals, it also is further threatening the survival of these endangered animals.
Studies show that these cetaceans, which once communicated over thousands of miles to forage and mate, are losing touch with each other, the experts said.
"Call it a cocktail-party effect," said Mark Simmonds, director of the Whale and Dolphin Conservation Society, a Britain-based NGO. "You have to speak louder and louder until no one can hear each other anymore."
An indirect source of noise pollution may also be coming from climate change, which is altering the chemistry of the oceans and making sound travel farther through sea water, the experts said.