The blue whale higher mammals voice, and his voice up to 188 decibels, their voices are not as complex as beluga whales, but the audio Zbzbadtha low unheard human ear can be recorded from a distance of up to 800 kilometers. Scientists have recently discovered that these whales reduce the frequency of their voice by 30% since the sixties of the last century, and one theory says that as a result because the whales no longer need to raise their voices over long distances, where their numbers have improved significantly since prevent whaling in 1966