Kitabı oku: «National Geographic Kids Chapters: My Best Friend is a Dolphin!»

A playful dolphin dances with a hula hoop. Credit 2

Have you ever been outsmarted by a dolphin? Tim Hoffland has. The clever dolphin who tricked him is named Kelly. Tim didn’t really mind being tricked. It just proved what he already knew: Dolphins are super smart! From the first time Tim saw a real dolphin, he knew that he wanted dolphins to be a part of his life.

Tim went to college in Wisconsin, U.S.A. During spring break one year, he went to an oceanarium (sounds like oh-shun-AIR-ee-um). That’s an aquarium with marine mammals. Marine mammals are animals that live in the water but breathe air—like whales or dolphins.

Tim watched the dolphin show there. He stared in amazement as the dolphins flipped and tumbled. With just a hand signal from their trainers, they walked on their tails. They’re really smart! he thought. After each trick, the dolphins swam up to their trainers. They opened their mouths for a tasty fish treat. They looked like they were smiling. Tim really was smiling. He was in love. And he knew what he was going to do after college. He would get a job as a marine mammal trainer.

Did You Know?

The largest dolphin is the orca. That’s right—the orca “whale” is actually a dolphin!

After Tim graduated, he searched the country for places that worked with cetaceans (sounds like sih-TAY-shunz). That’s what whales, porpoises, and dolphins are called. Millions of years ago, the ancestors of these animals had legs. They walked on land. But over time, they moved into the water to find new sources of food. There are two main types of cetaceans: toothed whales and baleen whales. Dolphins have teeth. So they are a type of toothed whale.

Tim applied for jobs wherever there were dolphins. Months went by. He was ready to give up. Then he got a call. The Institute for Marine Mammal Studies (IMMS) wanted him to fly down for an interview. It’s in Gulfport, Mississippi, U.S.A. Gulfport sits right on the Gulf of Mexico.

Tim was so nervous. He had looked for a job for a long time. This might be his only chance to work with dolphins. After he arrived, he met with one of the trainers. The trainer handed Tim a pair of rubber boots and coveralls. Then he told Tim to help unload a truck. The truck was filled with fish—49,000 of them! This is not my idea of a job interview, Tim thought. But he did it anyway. After all, he really wanted the job!

After he finished, he saw the dolphin tank. He stood looking at the animals. All at once, a dolphin popped up to the surface. She tossed him a hula hoop. He didn’t know what to do with it, so he flipped it back. She retrieved it! He looked into her eyes. She understands, he thought.

Tim got the job. He would help take care of dolphins and other animals. That meant unloading a lot of fish. It also meant learning a lot about dolphins. Tim learned about a dolphin’s body. The snout is called the rostrum (sounds like RAHS-truhm). The fluke (sounds like FLOOK) is the tail. There’s an opening on the back of a dolphin’s head. It’s called the blowhole. It’s like a nostril. Dolphins breathe through it.

Tim also studied the way the dolphins acted. They loved to play. They turned almost anything that floated into a toy. Sometimes, they acted like clowns. They decorated themselves in seaweed.

From the beginning, Tim worked with trained dolphins in the dolphin shows. But he wanted to learn something more. He wanted to know how to train the dolphins to do new things. One day, a new trainer named Mike Magaw arrived. Mike gave Tim books to read. And Mike let Tim watch him train the dolphins. Tim saw that dolphins are not trained with words, like dogs are. They are trained to follow hand signals. And, of course, they don’t get dog biscuits for a good job. They get fish!

Before long, Tim was helping Mike train the dolphins. Tim could see that the dolphins were enjoying the new tricks. They had a sparkle in their eyes. Tim understood that animals as smart as dolphins need to keep their minds active.

Credit 3, 4

Dolphins and porpoises are both whales. In fact, they are both toothed whales. But dolphins are not the same as porpoises. They are more like cousins. Dolphins have long snouts. Porpoises have smaller, rounded rostrums. Picture a pug dog in your mind. Now think of a sleek greyhound. The smushed-face pug is like the porpoise. Most dolphins are bigger than porpoises. The biggest difference between these animals is their teeth. Porpoises have rounded teeth. Dolphins have pointy chompers.

Tim also saw that the dolphins had different personalities. One young dolphin named Jacki was very sweet. She was Tim’s favorite. She was about the same age as another female named Kelly. Kelly was very smart. She learned new behaviors faster than any of the other dolphins.

Tim wanted to teach some of the dolphins to swim around the pool slapping their tails. That’s a hard trick. To teach dolphins tricks that use several behaviors, trainers use a whistle. For this trick, Tim gave each dolphin the hand signal to flap her fluke in place. When she did it, he blew the whistle. Then he tossed the dolphin a fish. After a while, he only blew the whistle. That meant Good job! It also told the animal that she had to do something more to get the treat. Tim held a target pole a short distance away. When the dolphin touched it with her rostrum, Tim blew the whistle again. Little by little, each dolphin swam around the tank, slapping her tail and touching the pole. Now it was time for a juicy fish!

Did You Know?

Dolphins can use tools. Some dolphins carry sponges in their mouths. They use them to protect their sensitive noses when they forage for food on the ocean floor.

Tim also taught the dolphins certain behaviors for their safety. One thing he wanted was to get their attention fast. For this behavior, Tim used a double whistle. It meant that the dolphins should stop what they were doing and come straight to the trainer. Tim didn’t know it at the time, but this training would help save their lives one day.