Some mammals, reptiles, and birds live there, too.
There is only one group of vertebrates not found in salt water.
These are the amphibians.
Fish have always lived
in the sea, of course. There are more than 13,000 different kinds, or species,
living in the sea. But the mammals found in the sea are descended from land
animals.
They have to come to the surface to breathe, because they have lungs, not gills.
They have to come to the surface to breathe, because they have lungs, not gills.
Fish in the ocean
Fish come in all sorts
of different shapes and sizes.
Some are flat so that they can lie on the seabed without being seen.
Eels have snakelike bodies.
Rays, like the skate, are kite-shaped and seem to fly through the water by flapping their huge “wings.”
Some are flat so that they can lie on the seabed without being seen.
Eels have snakelike bodies.
Rays, like the skate, are kite-shaped and seem to fly through the water by flapping their huge “wings.”
Mammals in the ocean
There are three groups
of mammals in the sea:
- whales and dolphins,
- seals and sea-lions, and
- some rare sea mammals called sirenians, which include the manatee and the dugong.
There are more than 75
different kinds of whales.
The blue whale is the largest animal that has ever lived. It can grow to be as long as 100 feet (30 meters)!
Whales need to come up to the surface for air, but sperm whales can hold their breath underwater for over an hour!
The blue whale is the largest animal that has ever lived. It can grow to be as long as 100 feet (30 meters)!
Whales need to come up to the surface for air, but sperm whales can hold their breath underwater for over an hour!
Dolphins and porpoises
are actually small whales. The killer whale is the largest walrus
dolphin.
Have you ever seen bottle-nosed dolphins perform in an aquarium?
They are very intelligent. They communicate with each other by blowing air through their blow-holes to make squeaks, whistles, and clicks.
Have you ever seen bottle-nosed dolphins perform in an aquarium?
They are very intelligent. They communicate with each other by blowing air through their blow-holes to make squeaks, whistles, and clicks.
Seals, sea-lions, and
walruses are the only sea mammals that move onto land to give birth to their
young. Walruses look like large seals with two long, pointed teeth called
tusks.
Reptiles in the ocean
Some turtles and
snakes live in the sea.
Like all reptiles, sea turtles are cold-blooded, so they live only in warm waters.
The females come out of the sea to lay their eggs in holes on sandy beaches.
Most sea snakes never leave the sea.
They swim by waving their flattened bodies from side to side and by using their oarlike tails as a paddle.
Like all reptiles, sea turtles are cold-blooded, so they live only in warm waters.
The females come out of the sea to lay their eggs in holes on sandy beaches.
Most sea snakes never leave the sea.
They swim by waving their flattened bodies from side to side and by using their oarlike tails as a paddle.
Birds in the ocean
Penguins spend much of
their lives in the sea, often hunting fish, their main food.
Instead of wings, penguins have flippers which help them to swim.
Penguins come to the surface of the water to breathe.
They move onto land to lay their eggs and raise their young.
Instead of wings, penguins have flippers which help them to swim.
Penguins come to the surface of the water to breathe.
They move onto land to lay their eggs and raise their young.
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