Submitted by guest blogger Cynthia Mills, reporting from Portland, Oregon.
Moby Dick was a sperm whale with an
attitude, and there is now new evidence that real sperm whales may
just be smart enough to act like Moby did. New recording techniques
suggest that they use collaborative hunting techniques on the same
level of sophistication as wolves and dolphins.
The new evidence was presented
yesterday by Bruce Mate of Hatfield Marine Station in Oregon at the
American Geophysical Union’s Ocean Sciences Meeting in Portland,
Mate has been spying on whales for a
long time now, following the travels of blue whales, humpbacks and
greys by attaching satellite tags to them. He found that what had
always been called migration was more complicated—whales sometimes
backtracked thousands of miles, as if they’d just remembered they’d
left the oven on at the beach house.
Now Mate is getting even more personal
with his spying. The satellite tags could only transmit information
when the whale surfaced; he is now using new tags that can track not
just surface position but the depth and duration of dives as well.
And to top things off he can listen in on their conversations, too.
The new tags record the whales’
activities for 28 days, and then they fall off. They transmit their
position by GPS, the scientists pick them up and download a computer
record of the whales’ travels, dives and sounds, down to an accuracy
of 2 meters (6.6 feet).
“Each animal is acoustic – each has
its own coda – some are triplets, doublets and each animal can
track the others by their sounds,” said Mate.
This becomes important when the whales
stalk their prey, Humboldt squid. What Mate can now see is that the
whales all dive together after the squid, but not the same way. Some
dive very, very deep, as deep as 1,200 meters (3,937 feet) while the
others stay more shallow.
“We’re hypothesizing the animals
are working together, creating a bait ball of squid.”
The new recording tags have a higher
movement resolution, so that Mate says they can even detect lunges of
the whales toward their prey. Mate says they even make a special
lunge sound, a sort of up-swept tone or creak, when they do.
This is unusual behavior for these
large whales. Humpback and grey whales make bubble nets to trap
krill, but there are no special roles for each whale – they are all
doing the same maneuver over and over again. The sperm whales are
performing different tasks – some seem to even specialize deep
versus shallow diving, doing it more often than the others.
This sort of collaborative hunting is
not unheard of in marine mammals. Dolphins have been found to herd
herring, holding a bait ball in one place while their team mates dive
in for bites.
Image: Animal Planet