To learn more about Martin Nweeia's narwhal-tusk project, go to narwhal.org/ (Narwhal.org) and web.med.harvard.edu/sites/RELEASES/
html/12_13nweeia.html (Harvard University).

For additional information about narwhals, see www.enchantedlearning.com/subjects/
whales/species/Narwhal.shtml (Enchanted Learning), www.narwhal.info/ (Narwhal.Info), and www.acsonline.org/factpack/Narwhal.htm (American Cetacean Society).

Books recommended by SearchIt!Science:

Whale — Vassili Papastavrou Published by Dorling Kindersley, 1993. Scientists believe that the mighty whale, the largest creature on Earth, evolved from a much smaller, hoofed animal that lived on land. Today, whales are found in every ocean, from the tropics to the Arctic. They even live in five of the world's largest rivers. This book explores the different kinds of whales. It describes how they court and give birth, their skeletons and body structures, and how they communicate. The book also has information about whale relatives—walruses, seals, dolphins, and dugongs. Large color photographs and drawings focus on such topics as the whale's evolution, the whale in the wild, and the whale's skeleton. There are also sections that show some products made from whales, myths and legends concerning these creatures, whale hunting and whale watching, and efforts to save the whale from extinction.

dentin The hard, bony part of a tooth that lies under the enamel. The dentin surrounds the pulp of the tooth.

enamel The hard, white substance that covers the part of the tooth that sticks out from the gums.

tusk A long, pointed tooth that sticks out of the mouth of some animals, such as elephants, walruses, and wild pigs. Tusks usually grow in pairs.

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