Blue Whales – Can You Hear Me Now?


Whales are social animals that like to keep in touch with each other. They have rather low frequency voices that range below that of a human singing bass. The low frequency sound carries for very long distances through water so that they can communicate over long distances.

The blue whales are one of our endangered species that live by sieving krill out of the sea water. They call to one another to indicate good feeding conditions with what are know as D-calls.

Unfortunately for the whales, we humans are causing more and more noise pollution with ship engine noise, explosions and powerful sonar. Melcón et al have followed a group of blue whales and monitored their vocal behavior under various conditions of noise pollution (1).

The general noise from passing ships is at multiple frequencies that are used by the whales and the whale’s response is to shout louder so that their colleagues can get the messages in spite of the noisy background. They also call more frequently to ensure that the messages are received.

If, as is their habit, the navy or the oilmen create explosions, the whales shut up for a little while until they can get their act together and get back to chatting in whale.

The bad thing, though, is powerful sonar signals. They shut right up and keep mum. Remember sonar is not broad-spectrum noise. We’re not very fond of piercing narrow frequency sound as I’m sure you’ll agree if you remind yourself of some alarm systems that can scare everybody off for miles around.

It can’t be much fun for the whales and it seems that it can quite put them off their feed. We should remember that noise pollution can be more than just irritating and that other species use different frequency ranges from ourselves. Whales are using low frequencies to get messages over huge distances, while Tarsiers in the Phillipines are using high ultrasonic frequencies that are outside the hearing of their predators and only travel very short distances.



Website @ http://jimgoodwinbooks.com/blog/

Leave a Reply