We use the name whale for about 70 kinds of animals. So how can you tell who is who? Not all 70 kinds live in the area around Cape Cod. In fact, some don’t even live in the Atlantic Ocean. But even the dozen or so that live are found in the northeast are different and easy to identify.

Remember, the category whale includes dolphins and porpoises. First – look at the animal’s size. Most dolphins are less than ten feet long; porpoises are not much more than six feet. Whales are much bigger, some are as long as a large airplane. Next – look at its mouth. Dolphins and a few whales have teeth for catching their food.

All the other whales have baleen – plates with fringe that hang from their upper jaws and trap their food, like a sieve. An easy way to tell if a whale uses teeth or baleen to catch food is to count the number of blowholes – breathing holes – on the top of their heads. Toothed whales have only one blow hole, baleen whales have two. Near Cape Cod the toothed whales that you’ll see most often are dolphins, smaller animals with patterns on their sides, or pilot whales, black animals with a white patch under their chins and a square head. The baleen whales you’ll most likely see are humpbacks, large animals with exceptionally long flippers, up to 12 feet in some cases.

Humpback whales have flat heads and a small fin on their backs. Another kind of baleen whale is the right whale. It has a large, square head and no fin. Now when you see a whale or a picture of a whale, see if you can guess the kind of whale – check its size, count the number of blowholes, look at the shape of its head, the size of the fin on its back, and the length of its flippers.

Is a whale’s a fountain of water? Both whales and people use lungs and noses to breathe air. But because whales live in the water their noses and lungs work differently from yours. Whales don’t breathe as often as you do; they breathe only when they are on the surface of the ocean.

That means they have to take in and let out a lot of air quickly. Their lung muscles are strong enough to force almost all the air out at once. One breath just about empties their lungs. In contrast, one of your breaths empties only part of your lungs. When a whale comes to the surface after a dive, it breathes out the “old” air quickly, all in one breath. Because the whale empties its lungs with such force, the air travels a great distances – 10, 20, even 40 feet. And because its nose is on the top of its head, the air goes straight up. This air is usually warmer than the air just above the surface of the ocean, so the water vapor (small particles of water carried in the air) condenses.

This condensed water vapor looks like steam – the same thing happens when you “see your breath” on a cold winter day. So the “spout” you see is not a fountain of water; rather, it’s a stream of warm air being forced out of the whales lungs, aka the whale’s breath. Some whale watch guides can tell you the kind of whale that has just come to the surface, even before they see the animal, based on the height and shape of their spout.

Because whales live in the ocean, many people think they are fish. But do you know that whales and dolphins are not fish? They are mammals. People are mammals too. Mammals are the group of animals that breath air using lungs, give birth to live young (rather than laying eggs), and feed their young with mother’s milk. All animals, including people, need oxygen, a chemical found in the air and in water. Fish use their gills to take oxygen from the water that they live in. But people get the oxygen we need by breathing air, using our lungs. Whales and dolphins use their lungs to breathe air also.

That’s one reasons why they come to the surface of the ocean. Sometimes they lie right at the surface of the water, with just a part of their back sticking out. Look closely at a picture of a whale or dolphin; can you see a nose on the whale? You can’t, because whales don’t have noses like you and me. Instead they have a hole – called a “blow hole” – on top of their heads. Sometimes when a whale breathes air out of its blow hole, it shows up as a spray or mist – called a “spout” – that can be seen many miles away. Blow holes are surrounded by muscles that keep the hole closed when the whale or dolphin is under water and open it when the animal is at the surface and needs to breathe.

In fact, some of the animals have two blow holes next to each other and others have only one. So when you see a picture of a whale, see if you can tell the difference. Pilot whales and dolphins have one blow hole; humpbacks, minkes and right whales have two.

Whales are not fish. But how do you know? You can tell the difference by watching the animal and asking yourself three questions:

Does its body move sideways or up and down when it swims?

Fish, including sharks, propel themselves through the water by using their body muscles to push their tails side-to-side.

Whales and dolphins push their tails up and down. The dolphin’s body muscles can generate enough power to push it through the water at speeds up to 20-30 miles per hour. That’s faster than you ride your bike, even at top speed.

Does it have gills or a nose?

Both fish and whales need oxygen. Fish use gills, open flaps along the sides of their bodies, to take oxygen from the water. A whale uses its nose and lungs, like you do. It’s hard to see a whale’s nose. It doesn’t stick out the way yours does because whales need streamlined bodies to help them swim fast. And they need a nose on the top of their head so they can breathe while the rest of their bodies are in the water.

So when you’re on a whale watch boat, look carefully. If you see something with gills, it’s a fish; If you see either one or two holes on the top of the head, it’s a whale and those are the “blowholes.”

Does it have a baby swimming with it?

Fish lay eggs and then leave the baby fish to grow up on their own. Whales and dolphins give birth to babies, just like people do. And then they feed and care for their babies for several months, sometimes even for several years. So now that you know the questions to ask, you should be able to tell that a whale is not a fish.

How would you describe the shape of a whale or dolphin? Wouldn’t you say they are very streamlined? Very few appendages (like your arms and legs) stick out to slow the animal down as it swims through the water. A whale’s body is shaped like a submarine, or the body of an airplane.

The smooth, rubbery skin, the lack of hair, and no ears sticking out also contribute to the sleek body designed for speed in the water.

But it takes more than a sleek body to maneuver in the water. Remember, when whales and dolphins are going after their food, they not only swim at the surface, they also dive to great depths. They need rudders and propellers.

Look closely at a whale or dolphin – you’ll see that many have a dorsal fin, the fin that sticks up from the back of the animal. Scientists believe that the dorsal fin acts as a stabilizer or a rudder. You might think that the dorsal fin has bones in it, like the fins on fish. But the whale’s dorsal fin has no bones. Instead, it is made up of dense tissue, somewhat like a ridge of thick, folded skin.

You’ll also see flippers low on the sides of the animals. Those flippers are used for steering, for balancing, and for stopping. But they are not used for moving forward through the water.

Forward motion is created by the whale’s or dolphin’s tail, or flukes, moving up and down in the water. It serves as the propeller. Powerful muscles running along the backbone and sides of the whale’s body move the tail up and down in the water, providing the power that pushes the animal through the water, or deep into the ocean. In fact, one way to remember that whales are not fish is that fish move their bodies sideways when they swim; whales move their bodies up and down.

When you’re watching the actions of the biggest creatures on earth, ask about what animals they are related to. Are they fish? Are they related to sharks? Are they related to cows and camels?

If you said yes to the last question, you are right! Some scientists believe that the whale’s oldest ancestor is a four-legged, hyena-like animal that lived on land more than 50 million years ago.

It took about ten million years for the changes to happen. During that time the animal began spending more and more time in the water, where it had little competition for food. As it changed to a whale, its body shape became more streamlined so that it could move through the water faster. It also lost most of its hair and instead developed a layer of fat, or blubber, to keep warm. Its head changed shape so that it could see and breathe easily on the top of the water. Its eyes moved to the sides of its head and its nose moved from the front of its face, where yours is, to the top of its head.

When you’re looking at the whales, try to find its nose, the blowhole. Some kinds of whales have two blowholes and some have one. Whales in the waters around Cape Cod that have one blowhole are pilot whales and all kinds of dolphins. Humpback whales, minkes, and right whales have two blowholes.

Think about how you breathe when you are swimming: you have to lift your head out of the water. But a whale can keep most of its head in the water, watching for food, or looking after it’s young while it is breathing.

What you would eat if you lived in the ocean? If you said fish and squid, you’d be right.

But there’s a second correct answer – some whales eat ocean creatures called plankton that are so small they are hard for us to see.

Now think about how whales eat fish and squid. That’s easy – pretty much the way you eat your dinner, by using your teeth.

But what about catching and eating the tiny creatures? Teeth are not much help. And yet, these huge creatures thrive on this diet. They have figured out a different way to eat.

These whales are known as “baleen whales.” Look closely. They don’t have teeth. Instead, they have baleen plates hanging from their upper jaw. Baleen is made of a substance similar to your fingernails with a row of fringe along one side.

Baleen whales swim through the water with their mouth open, taking in large volumes of water that contain the tiny ocean creatures. The fringed baleen then acts as a sieve – the whales squeeze the water out through the baleen, leaving their food caught on the baleen. Then they use their tongue to wipe the baleen clean before swallowing their food.

In the northeast U.S., the common toothed whales are pilot whales, dolphins, and porpoises. Common baleen whales are humpbacks, minkes, and right whales.