Habitat is important to keep young right whales undetected

Female southern right whales make massive migrations to give birth in areas that appear to be dangerous. They seem to prefer shallow bay habitats close to humans and with little food, but why? 

It’s long been hypothesized that the whales may choose such counterintuitive habitats to birth and nurse their young because of lack of predators. Now, a study from Syracuse University’s Bioacoustics and Behavioral Ecology Lab proposes another theory.       

The new research suggests that shallow sandy bay habitats may allow acoustics optimal for whale communications, allowing mother whales to better keep in touch with their babies while not being overheard by distant predators. 

“Animals that communicate using sound must balance the need to be heard by their intended audience and the risk of being overheard by eavesdroppers such as predators,” explained study lead author Julia Zeh, a PhD candidate in Biology in the College of Arts and Sciences.

The research was carried out in Australia, South America and Africa at three different whale nursery sites.  

Southern right whales are already known to avoid being overheard by predators by reducing their call amplitude or being silent entirely. They also sometimes use frequencies of calls that make them harder to locate. 

All of these techniques are known collectively as “acoustic crypsis.” The scientists suggest that the strategy used by the whales is merely another form of acoustic crypsis – this time focused on habitat selection.

“We found that southern right whale mothers and calves spend time in specific locations where they can hear each other, but other animals can’t hear them,” said Zeh. “These results follow on some interesting recent papers that recorded quiet calls, or essentially whispers, from right whale mothers and calves.”

The scientists plan on following up on this research to investigate how common a habitat selection approach to acoustic crypsis may be.

The study is published in the journal Royal Society Open Science.

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By Zach Fitzner, Earth.com Staff Writer