How many rows of teeth do sharks have in their mouths?

Check out those rows of teeth!

During last Saturday’s P3 class, Eason was surprised to learn that sharks have multiple rows of teeth in their mouths. For the grammar portion of our Primary 1 through Primary 3 classes, we use a really great series of texts from Oxford University Press and that day’s exercises featured a section on “shark facts” that included the following tidbit:

Some sharks have as many as fifteen rows of teeth.

The San Diego Natural History Museum maintains a really great Sharks FAQ and they confirm that sharks generally have numerous rows of teeth … and explain why:

Most sharks have 5 to 15 rows of teeth in each jaw. Unlike human teeth, shark teeth don’t have roots to hold them in place, so their teeth are easily broken off. A tooth usually lasts about a week before it falls out. When this happens, the tooth behind it moves up to replace it. A new tooth can be replaced in as little as 24 hours. Sharks keep replacing their teeth all their lives. As the shark grows, its new teeth keep pace and grow larger than the ones that are replaced.

I’ve included a photo that shows several rows of shark teeth with the flesh of the shark’s gum removed.