The Tooth on the Beach

Part One · The tooth

Emeka found a tooth on the beach. It was small and dark and shaped like a triangle, with edges that were very sharp. "That is a shark tooth," said Grandma. "Sharks lose teeth all the time." Emeka held it up to the sun. Where had it come from? And what else did a shark have?

"A shark has rows and rows of teeth," said Grandma. "When one breaks off, a new sharp tooth takes its place. Over its whole life, a shark can lose thousands of teeth. That is why people find them on beaches." Emeka tried to count the teeth in his mind, and he soon gave up. He tucked the tooth into his pocket.

Part Two · No bones

That night, Emeka read a book about sharks, and the first page held a big surprise. A shark has no bones! Its whole skeleton is made of cartilage, the same bendy stuff that is inside your ears and the tip of your nose. Emeka wiggled his ear and felt it bend. A shark is built from that.

The book said that shark skin feels like sandpaper. It is covered with tiny scales that are shaped like teeth. Emeka rubbed his hand across a piece of sandpaper from the garage. He tried to picture a whole fish made of it. It was a lot to imagine, and it made him laugh.

Part Three · Big and small

The next day, Emeka asked his teacher, "What is the biggest shark?" "The whale shark," she said. "It is the biggest fish in the sea. It can grow to about sixty feet long." Emeka took big steps across the yard to see. Twenty steps! And the whale shark eats tiny plankton, which it filters out of the water.

"Is every shark that big?" asked Emeka. "Not at all," said his teacher. "The smallest one is the dwarf lanternshark. It is full-grown at only about eight inches, as long as a pencil." Emeka drew a lanternshark next to the whale shark. His picture needed a very long piece of paper.

Part Four · Fast and sneaky

"And what is the fastest?" Emeka asked next. "The shortfin mako," said his teacher. "It can zoom at forty-three miles an hour for a short burst." Emeka ran across the yard as fast as he could, but he did not even come close. He decided that the mako was the champion, and he gave it a gold medal on his picture.

At the library, Emeka learned that a shark can find a fish hidden in the sand. Fish and other sea animals give off a faint electric signal, much too small for you or me to feel. A shark can feel it. Emeka closed his eyes, but he felt nothing at all. A shark has a sense that people do not have.

Part Five · Heads and eggs

Emeka's favorite shark was the hammerhead. Its head is wide and flat, like a hammer, with an eye and a nostril at each end. Nobody knows for sure why it has such a head. Scientists think it may help the shark follow smells in the water. Emeka put a ruler across his forehead and made a hammerhead face.

"Do sharks lay eggs?" asked Emeka. He looked it up. Most sharks are born live, but some lay eggs in a tough case that feels like leather. Emeka held up a leather wallet and tried to picture a baby shark curled up inside one.

The oldest shark of all is the Greenland shark. It may live for more than four hundred years. Emeka pretended his house had been built four hundred years ago, long before cars or electric lights. A Greenland shark could have been swimming that whole time.

Part Six · Staying safe

"Are sharks dangerous?" Emeka asked Grandma at last. Grandma thought for a moment. "A bite can hurt, so we are careful," she said. "But bites are very rare. More than thirty kinds of sharks have ever been known to bite a person. People are not what sharks eat."

"How can I stay safe at the beach?" asked Emeka. "Swim with a buddy," said Grandma, "and stay where the grown-ups can see you." Emeka held his buddy's hand. His buddy was Grandma, and she grinned. They waded in together, up to their knees, and watched the waves.

Part Seven · A shelf

That evening, Emeka put his tooth on the shelf and looked at it. It had been part of a shark that keeps growing new ones. He turned it over in his hand and felt its sharp tip. Which shark would you want to learn about first?