A shark tooth is one of the numerous teeth of a shark. Sharks continually shed their teeth, and some Carcharhiniformes shed approximately 35,000 teeth in a lifetime. In some geological formations, shark's teeth are a common fossil. These fossils can be analyzed for information on shark evolution and biology, especially because the teeth are often the only part of the shark to be fossilized, in fact fossil teeth comprise much of the fossil record of the Elasmobranchii, extending back hundreds of millions of years.
The most ancient types of sharks date back to 450 million years ago, during the Late Ordovician period, and they are mostly known from their fossilised teeth. The most commonly found fossil shark's teeth are, however, from the Cenozoic (the last 65 million years).
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Famous quotes containing the words shark and/or tooth:
“Oh, the shark has pretty teeth, dear—
And he shows them pearly white—
Just a jackknife has Macheath, dear—
And he keeps it out of sight.”
—Bertolt Brecht (1898–1956)
“Had I but awakened from sleep
And called her name, she had heard
It may be, and had not stirred,
That now, it may be, has found
The horn’s sweet note and the tooth of the hound.”
—William Butler Yeats (1865–1939)