SMART ARE WHALES?
March 17, 2002
have the largest brains known." This statement, and many
more in "Whales and Dolphins in Question," will come
as a surprise to people who think the human brain surpasses
all others in size. Written by James G. Mean and Joy P. Gold,
and published in 2002 by the Smithsonian Institution Press ($24.95),
the high quality paperback poses questions many people ask about
these largest of all animals. The answers are fascinating, educational,
and often surprising. The book can be ordered directly from
the Smithsonian Institution Press by calling 202-275-2206 or
Whales are mammals belonging to the order Cetacea, which consists
of 86 different species, including dolphins, porpoises, and
narwhals. Some species, such as sperm whales of "Moby Dick"
fame, blue whales (the largest animals ever known on Earth),
and bottlenose dolphins are familiar to almost everyone. I like
the book's distinction between a whale and a dolphin: "Any
cetacean so large that it cannot be moved readily by a small
group of people is called a whale." The words "dolphin"
and "porpoise" are used for small cetaceans of different
kinds depending on the particular species and geographic region.
In answer to the question "what do whales eat?" the
authors discuss the range in size of marine animals whales consume,
from small crustaceans known as krill and copepods to other
whales. Giant blue whales feed on shrimp-sized krill that occur
in the millions in some regions. One feeding technique is to
lunge into a school of fish with the mouth open then close the
mouth and force the water out through a network of bristles
known as baleen. The prey is held behind for the whale to swallow.
An unusual form of prey capture by humpback whales is known
as bubble netting in which the whale swims in a circle while
blowing bubbles. A circular wall of bubbles is created, alarming
fish and driving them into the center Then the whale surfaces
inside of the bubble "net" with an open mouth, eating
anything that has concentrated in the area.
A question I have wondered about is "how and why do narwhals
use their tusks?" Narwhals are a sort of marine unicorn
of the Arctic Ocean, with a long, protruding tusk (up to nine
feet long!) that develops from the single, left upper jaw tooth
in males. Narwhals have no bottom teeth, and females usually
have no tusks. As it turns out, the true use of the narwhal's
tusk has never been documented. My own view is that when a trait,
especially a weapon, occurs only in males, it evolved for one
purpose: to fight other males for mates.
An appendix in the book will prove useful to many young people
by providing answers to a question asked many times each year:
"How do I become a marine biologist?" The section
discusses the salaries of marine mammal scientists (averaging
$30,000 to 40,000 per year), who employs them (zoos and aquariums,
the U.S. Navy, environmental groups), and even how to become
a marine mammal veterinarian.
would be expected, one focus is on the conservation plight faced
globally by whales, although little is said of the international
politics surrounding efforts by Japan and Norway to continue
commercial whaling. The authors' answer to "what is the
prognosis for whales and dolphins" offers an optimistic
view of a return to their former numbers by many species. But
aside from the perils some species face from modern whaling
ships, whales are also victims of collisions with various sea-going
vessels, accidental captures in fishing nets and other gear,
and the insidious and less-obvious impacts of pollution in ocean
success story that keeps hope alive for the fate of these fascinating
creatures of the ocean depths is that of the California gray
whale, which was "thought to be extinct in the early 1900s,
[but] has come back." Let's hope we will be able to say
the same about the many other species of whales and dolphins
in years to come. Having the world's biggest brains will be
little help to whales unless we begin using our slightly smaller
brains in some environmentally sensible ways.
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