Ocean songs are drowned out

The songs that whales and dolphins use to communicate, orient themselves and find mates are being drowned out by human-made noises in the oceans, U.N. officials and environmental groups said this week.

That sound pollution -- from increasing commercial shipping and seismic surveys to a new generation of military sonar -- is not only confounding to the mammals, it is an added threat to the survival of the 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 at a U.N. wildlife conference in Rome.