Ocean life

Oceans cover almost tree-quarters of our planet. These watery worlds are filled with an amazing variety of living things. Many creatures are only found in the sea, such as octopuses, jellyfish and giant tube worms. There are also fish, shellfish, birds, mammals, sea snakes, seaweeds, and even ocean insects.

The word “ocean” usually means a huge, salty sea covering a large area of the Earth. There are five main oceans. The biggest are the Pacific, Atlantic and Indian oceans. The Artic and Antarctic (or Southern) oceans are at the top and bottom of the world.

Seas and oceans Wide and deep

Seas are really no different from oceans - they are just smaller. The Red Sea, for exemple, is a narrow sea lying between Africa and Arabia. Seas can be part of larger oceans - such as the Caribbean Sea, which is in the Atlantic Ocean.

One reason there are so many sea creatures is that the oceans are truly huge. They are also very deep. Different types of creatures live at different levels, from the sunny shallows to the dark and gloomy depths.

Oceans are so big and deep that there may be many sea creatures still waiting to be discovered.

Scientists often find new ones, such as octopuses, sharks and strange, deep-sea fish.