|
 Scientists said on Wednesday they tracked these medium-sized
whales off the coast of California using satellite-linked tags as
the creatures dove down nearly 1.9 miles and spent two hours and 17
minutes underwater before resurfacing.
Those are breath-taking accomplishments for an air-breathing
creature. In fact, those figures represent both the deepest and the
longest dives ever documented for any marine mammal, said Greg
Schorr of the Cascadia Research Collective in Olympia, Washington,
who led the study published in the journal PLOS ONE.
"Many creatures live at the depths these whales dive to, including
their likely primary prey of squid and fish. However, there is a
major difference between these whales and the other creatures living
deep in the ocean — the fundamental requirement to breathe air at
the surface," Schorr said.
"Taking a breath at the surface and holding it while diving to
pressures over 250 times that at the surface is an astounding feat,"
Schorr added.
By way of comparison, the record for a person holding his breath
underwater is 22 minutes, according to the Guinness Book of World
Records. A person, of course, would never survive the bone-crushing
water pressure at those stupendous depths.
Cuvier's beaked whales are widely distributed in many deep-water
regions from the tropics to cool temperate waters, though not in
polar regions. They measure up to about 23 feet long, with stout
bodies shaped a bit like a torpedo. Their foreheads slope into a
short beak with a slightly upturned mouth — leaving them with a
vaguely "smiling" appearance.
Their color ranges from gray to a reddish-brown to a pale white.
Some are marked with linear white scars caused by males raking other
males with their teeth, perhaps while competing for females. They
feed primarily on deep-water squid and some fish near the ocean
floor.
"HIGHLY ADAPTED"
"This species is highly adapted to deep diving, spending less than
two minutes at the surface between dives," Schorr said. "These are
social, warm-blooded mammals that have adapted to actively pursue
their prey at astounding depths — all while up to 1.8 miles away
from their most basic physiological need: air."
[to top of second column] |
A number of marine mammals are known for their deep-diving
abilities. The sperm whale, the largest of the toothed whales, also
swims into the ocean depths to find prey. But the deep dives of
sperm whales generally are less than six-tenths of a mile and are
followed by much longer periods of time spent at the surface, Schorr
said.
Elephant seals have been documented making incredibly long and deep
dives. Until this new data about Cuvier's beaked whales, the records
for deepest and longest dives by a marine mammal had been held by
elephant seals — so named because adult males have large noses that
look a bit like an elephant's trunk.
Elephant seals have been documented diving to depths of 1.5 miles
and staying under water for two hours, Schorr said. But their deep
dives are infrequent and followed by a comparatively long recovery
time at the surface.
To track the Cuvier's beaked whales, the scientists used
satellite-linked tags that provided data on the start and end times
of a dive and the maximum depth of each dive, as well as the time
between dives. The tags were attached to the dorsal fin using two
small titanium darts.
The scientists tracked eight whales off the coast of Southern
California. They were tagged in 2010, 2011 and 2012 roughly 80 miles
west of San Diego. They amassed more than 3,700 hours of diving
data.
(Reporting by Will Dunham; editing by Stephen Powell)
[© 2014 Thomson Reuters. All rights
reserved.] Copyright 2014 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
