Dolphins are a medium sized animal that lives in the water, mainly the sea but they are also found in lakes and rivers. They are not fish, as they need to come to the surface to breathe, the same as we do when we are swimming. Dolphins eat mostly fish. They are intelligent and can be taught tricks.
Scientific name: dugong dugon
Dugongs are closely related to manatees, but unlike manatees they live in salty water. Dugongs are mammals, and they eat seagrasses in shallow water near the coast.
Scientific name: family: trichechidae, genus: trichechus
Manatees, also called sea cows, are mammals closely related to the dugong. They grow to around 3 meters long, and weigh around 4,000 pounds (1,700kg). They eat plants in fairly shallow water around the coast and in rivers.
Scientific name: Monodon monoceros
Narwhals are a kind of medium sized whale that has a long tusk growing from the middle of their head, like a unicorn's horn. They live in the northern part of the world, in the arctic waters.
Scientific name: Orcinus orca
The orca, or killer whale, is the largest member of the dolphin family. They are found in oceans all over the world. Orcas are hunters, and will eat fish, sharks, seals and even whales. They grow to around 6-8 metres long, and can live to be 80 years old, although most males only get to be 30 and females 50. A female orca will have one calf every 5 years.
Scientific name: pinniped
Seals are a large animal that spends most of its time in the sea. Seals eat fish, and come up onto the beach to rest and have baby seals. The closest land relative to the seal is the bear, and their closest relatives in the water are walruses.
Scientific name: odobenus rosmarus
A walrus is a large animal that spends most of its time in the sea. They eat clams, sea snails and other animals from the bottom of the sea. They can live to about 50 years old, and a male walrus can grow to weigh between 1,600 and 1,900kg, and get 10-12 feet long. They are distantly related to the seal.
Whales are a large animal that lives in the sea. They are not fish, as they need to come to the surface to breathe, the same as we do when we are swimming. There are many different varieties of whale. Some eat fish, penguins and seals, but the majority of whales have a large mouth full of tiny bristles that they use to filter tiny sea animals out from the water to eat. The whale is closely related to the dolphin.