Title: Ivory Identification Guide - U.S. Fish and Wildlife Service Forensics Laboratory
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Content: Click to see cross section of sperm whale tooth
NARWHAL
(Monodon monoceros)
The narwhale is a rarely seen arctic whale. The male of this species has a single left tusk that is a modified upper incisor. The tusk is spirally twisted, usually in an counter-clockwise direction. In a mature specimen the tusk can be from two to seven meters long. Enamel may be present at the tip of the tusk. The cementum frequently displays longitudinal cracks which follow the depressed areas of the spiral pattern. As a result, narwhal tusk cross-sections are rounded with peripheral indentations. The cementum is separated from the dentine by a clearly defined transition ring. Like killer and sperm whale teeth, the dentine can display prominent concentric rings. The pulp cavity extends throughout most of the length of the tusk giving cross-sections a hollow interior.