Abigail W. Leonard Special to LiveScience LiveScience.com1 hour, 2 minutes ago
Deep below the ocean's surface, blue whales are singing--and for the first time, scientists think they know why. Researchers
from the Scripps Institution of Oceanography recorded the sounds and say they offer new insight into the behavior of the passenger
Using tags suctioned to the whales' bodies, researchers tracked the whales
and found that as they feed, they send out calls to let each other know where they are, each group employing a different sound.
The noises play a similarly important role during mating season when males
sing long, low-pitched songs to indicate their reproductive fitness to females. Females select mates based
on size and estimate that by evaluating males' songs: Larger males can take in more
air and hold notes longer.
The research appears in the January 25 issue of the Marine Ecology Progress
A related study, also by Scripps researchers, found that there are distinct
"dialects" of whale-speak in different regions of the ocean. The finding could have implications for preservation efforts.
The scientists used acoustic recordings to delineate nine population regions
worldwide. They found the whales weren't evenly distributed, though: Populations using a "Type 1" call, for
example, live within a narrow band of ocean hugging the North American coast, while whales that use a "Type 4" call are spread
over a large swath of the Northern Pacific Ocean.
The second study was published in a recent issue of the Journal of Cetacean
The scientists say the dialect findings could help guide conservation efforts
for blue whales, whose numbers dwindled to dangerously low levels before whaling moratoria were enacted: There were once an
estimated two to three hundred thousand in the Southern hemisphere, but today that number is closer to 1,000, Scripps scientist
John Hildebrand told LiveScience.
"By listening to the animals," he said, "you can tell something about the
areas in which they are interacting to breed and that's important to know for managing and conserving the animals."