HOW SMART ARE WHALES?

by Whit Gibbons

March 17, 2002



"Whales 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 emailing mlitts@sipress.si.edu.

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.

As 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 habitats.

One 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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