John Hildebrand of the Scripps Institution of Oceanography studies whale sounds and says he’s been hearing something new lately.
“They’ve been shifting the frequency. They’ve been shifting the pitch to be lower each year. And that shift in pitch has resulted in song that is now about 30 percent lower than it was in the 1960s,” he says. He says the change is happening in blue whale colonies all over the world.
Hildebrand believes the change is tied to the elimination of blue whale hunting. Before hunting was banned in 1966, the numbers of blue whales were dangerously low.