JULY 11,
2019
Most
mammalian new mums are fiercely protective of their precious offspring; even
5-8 m long southern right whale calves are vulnerable to attack by voracious
killer whales. Mia Nielsen from Aarhus University, Denmark, explains that whale
mothers and calves often try to hide from predators by gravitating to cloudy
water. But the loss of visual contact could force mothers and their young to
call to each other more, increasing the risk of attracting the wrong attention.
Knowing that humpback whale mothers resort to whispering to their young to
protect them from harm, Nielsen and her colleagues, Lars Bejder from the
University of Hawaii at Manoa and Peter Madsen, also from Aarhus University,
decided to listen in on the conversations between southern right whale (Eubalaena
australis) mothers and their calves, to find out how they go unnoticed. The
team publishes its discovery that the mothers and their calves shelter in the
noisy surf, stay in close proximity and effectively whisper—calling softly less
than once per dive—to avoid attracting any unwanted attention in Journal
of Experimental Biology.
'One of the
initial challenges was getting to know the whales in our study area', says Nielsen, who travelled to Flinders
Bay—off the southern tip of Western Australia where the whales breed—with
Madsen, Bejder and Fredrik Christiansen to track the graceful creatures. 'The
number of whales that frequent the bay is low', says Nielsen, who admits that
she was surprised when they eventually located the females with their calves in the surf zone close to shore; which puzzled the
researchers. Why were the mothers taking
refuge in the most turbulent water? Were the crashing waves providing acoustic
cover? And would the mothers and their offspring call to each other more
frequently in the stirred-up water to keep in touch?
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