Handout 5-C

Cheri Reechia, a graduate student at the Woods Hole Oceanographic Institution, is using the data logger to study vocalizations and social behavior among groups of beluga whales at four aquariums. Belugas long ago were nicknamed the "canaries of the sea" because sailors could hear their plaintive calls even through the wooden hulls of their sailing ships.

She believes understanding their vocal and social behavior will be helpful for captive-animal husbandry, perhaps providing information on changing social dynamics, breeding conditions, or the general health of captive belugas. Long-term, she hopes to use dataloggers to study wild beluga society, to track their movements and provide data for their protection in the ocean.

Do whales use echolocation all the time?

Whales and dolphins echolocate-emit clicking sounds that bounce off prey or objects in order to locate and identify them. Some scientists think that captive whales and dolphins do this much more than wild populations. Although all whales chatter up a storm to keep in contact with each other and to communicate (what, scientists don't know,) some whales may not use echolocation at all, but may find their prey simply by listening. The fact that sperm whales and right whales are struck by boats suggests they may not be using echolocation to avoid these large objects. Dolphins, too, may turn off their echolocation while traveling, which would explain why they become entangled in drift nets instead of leaping over them.

Scientists have determined that whales stay in touch with each other using a variety of vocalizations. Killer whales make plaintive, wailing noises. Fin whale pods typically have one whale that dominates the conversation while others take turns answering, according to Mark A. McDonald and colleagues at Scripps Institution of Oceanography. Blue whales, they found, call for 20 seconds, pause for 20 seconds, and then repeat the 20-second call.

As underwater noise pollution increases from boat engines, submarines, and oceanographic experiments, researchers feel it is critical to learn more about the way whales use sound in the wild in order to prevent human activities from disrupting the lives of cetaceans.

(Source: "Whale Chatter: Making sense of marine mammals' clicks and calls," Science News, May 25, 1996)



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