Subject: FOOD CHAIN (fwd)

Michael Williamson (williams@whale.simmons.edu)
Tue, 15 Oct 1996 14:55:31 -0400 (EDT)

Date: 15 Oct 96 13:02 EST
From: CLAPHAM.PHIL@SIMNH.SI.EDU
To: "CLAPHAM,PHIL"@SIMNH.SI.EDU, "G.ask [Private Mail Group]"@SIMNH.SI.EDU,
    "GREENER@PCIX.COM"@SIVM.SI.EDU
Subject: Copy of: FOOD CHAIN

Original message: "FOOD CHAIN"
From: <<greener@pcix.com>>

We are fourth grade students at Solomon Schechter 
Day School in Stoughton, MA.  We are writing big 
books about whales, and we need some information 
about the food chain of the whale.  If you have any 
information or diagrams, please send them to us 
through email.
Rachel Skerker and Keren Philosophe

Hi Rachel and Keren:

Here's a little information on food chains in whales, and a suggestion'
for some further reading.

First, you need to know that whales, dolphins and porpoises are
together all called "cetaceans" (it's pronounced "se-TAY-shuns")
and there are in all about 78 species (different kinds).  We
divide them into two groups, called the toothed whales and the
baleen whales.  The toothed whales include most of the species,
like dolphins, porpoises etc.  the only really huge whale with
teeth is the sperm.  The baleen whales don't have teeth at all,
but something called "baleen", which is like a big filtering
system in their mouth.  The baleen whales include all of the
very big whales except the sperm whale.

Generally, toothed whales eat things like fish or squid, and they
often take them one at a time (rather than in a big school).  The
baleen whales eat small fish like herring, sand lance or capelin,
and they take hundreds or thousands of them in at one gulp (they
use the baleen to strain the water out of their mouths, leaving
the food inside).  Baleen whales also eat krill, which is rather
like tiny shrimp and which also is found in big schools or
patches containing sometimes millions of individual animals.

Not all baleen whales eat the same thing.  Blue whales eat ONLY krill
for the most part.  Fin, minke, humpback and Bryde's whales eat
krill and fish.  Sei whales eat fish, krill and small planktonic
creatures called copepods.  Right whales eat copepods and not much
else (copepods are about the size of a grain of rice, so they
have to eat millions every day!)  Bowhead whales eat copepods,
krill and sometimes small critters that live on the bottom of the
sea, and gray whales do the same.

Toothed whales also eat a variety of things.  Sperm whales eat
sometimes very large (giant) squid.  Killer whales eat either
fish or other cetaceans and seals.  Dolphins eat lots of different
fish or squid, among other things.

The food chain itself is long.  It starts with what are called
phytoplankton, which are the billions of microscopic plants that
are the bottom of all food chains in the ocean.  Plankton,
incidentally, is the name we give to just about anything in the
ocean that cannot swim against the tides or currents.  The
phytoplankton are eaten by tiny animals, called the zooplankton;
these are eaten by fish and other things (and directly by some
whales like right whales - copepods are zooplantkon, and so are
krill).  Then the fish are eaten by bigger fish and by whales.

Baleen whales generally eat smaller fish because - even though they
have the biggest mouths of any animal on Earth - they have on very
small throats, only a few inches across.  believe it or not, the
throat of a huge blue whale (which may be 100 feet long) is only
a few inches wide!  Dolphins and sperm whales will eat small fish
too, but can also eat bigger fish and squid.  Killer whales
will eat even bluefin tuna, which get up to 1500 lbs!

So here's the simple food chain (it's actually a lot more
complicated than this, but...)

MANY TOOTHED WHALES
        |
   Bigger fish
        |
  Smaller fish --- SOME BALEEN WHALES
        |
   Zooplankton --- SOME BALEEN WHALES
        |
  Phytoplankton

Now go to your library and look up in an encyclopedia the
following:

baleen whales
cetaceans
food chain
plankton

A good book to read on cetaceans is "The Sierra Club Handbook of
Whales and Dolphins" by Steve Leatherwood and Randall Reeves.
(I also recently published a book called "Humpback Whales" which
talks about food chains in cetaceans.  It's published by
Voyageur Press and has lots of nice color photos of humpbacks!)

Good luck with your report!

Phil Clapham