Subject: Baleen whale food and migration

Phil Clapham (phillip.clapham@noaa.gov)
Tue, 05 Oct 1999 09:23:52 -0400

Hi:

Great question.  The answer is... we don't really know.  There is no
evidence that baleen whales echolocate the way that toothed whales (like
dolphins) do.  It's a reasonable assumption that whales know a certain
area for feeding, and are clued into potentially good feeding spots by
the shape of the seafloor and oceanographic information; this is because
their food - small fish or plankton - are much more likely to be found
in certain places, especially where there is a slope to the seafloor. 
They may be able to hear noises that fish make, and it's also possible
that they have a good sense of smell.  If you look at the brain of a
baleen whale, the "olfactory lobe" (the bit that processes smell
stimuli) is pretty well developed, which is not the case in toothed
whales (since they have echolocation, they presumably don't need
smell).  I would guess that baleen whales use a sense of smell at the
surface (not underwater), since fish schools and plankton patches often
give often a strong smell which can be detected easily (even by humans)
downwind.

On migration, we don't know for sure how whales do this, but can guess. 
Lots of animals have a biomagnetic sense - that is they can "read" the
Earth's surrounding magnetic field and use it like a map.  It's likely
that whales have this capability, but no one has proved it.  Recent work
By Chris Clark at Cornell University on blue whales indicates that they
make very, very loud sounds at very low frequencies (180 dB, 14 Hz)
which may be long-distance echolocation.  The idea is that they might
bounce these sounds off islands, seamounts or other oceanic features,
and by listening to the returning echo recognize the "landmark" and know
where they are.  The amazing thing is, the sound travels hundreds of
miles, so blue whales may actually do this over very long distances!

Phil Clapham


> philler wrote:
> 
> Hi! I am trying to find out how baleen whales find food and navigate
> if they do not use echolocation and cannot see very well.
> Thanks!
> Matt Hiller
> 

-- 

Phillip J. Clapham, Ph.D.
Large Whale Biology Program
Northeast Fisheries Science Center
166 Water Street
Woods Hole, MA 02543

tel (508) 495-2316
fax (508) 495-2066
Internet: phillip.clapham@noaa.gov