Top 10 heaviest sea animals in the world.

Blue whale - The blue whale is the biggest animal on Earth and the heaviest sea animal, weighing up to 173 tons (191 tons). That's about the same weight as 30 elephants! They eat tiny shrimp-like creatures called krill, and can grow up to 30 meters (98 feet) long.

Fin whale - The fin whale is the second-largest animal on Earth and the second-heaviest sea animal, weighing up to 74 tons (82 tons). They're sometimes called the "razorback whale" because of the ridge on their back. Fin whales can grow up to 27 meters (89 feet) long.

Bowhead whale - The bowhead whale is a type of whale that lives in the cold waters of the Arctic and sub-Arctic. They can weigh up to 100 tons (110 tons), which is about the same weight as 18 elephants! Bowhead whales can live for more than 200 years and can grow up to 18 meters (59 feet) long.

Humpback whale - The humpback whale is known for its long, melodic songs and acrobatic displays like breaching (jumping out of the water). They can weigh up to 48 tons (53 tons) and grow up to 16 meters (52 feet) long.

Sperm whale - The sperm whale is the largest toothed whale and can dive to great depths in search of giant squid. They can weigh up to 57 tons (63 tons) and grow up to 18 meters (59 feet) long.

Whale shark - The whale shark is the biggest fish in the world and can grow up to 12.65 meters (41.50 feet) long. Despite their name, they don't eat whales - they eat plankton and small fish. tons (23.7 tons), which is about the same weight as 3 elephants!

Basking shark - The basking shark is the second-largest fish in the world and can grow up to 10 meters (33 feet) long. They're called "basking" sharks because they often swim near the surface with their mouths open, basking in the sun. They can weigh up to 4.5 tons (5 tons).

Giant manta ray - The giant manta ray is the biggest species of ray and can have a wingspan of up to 7 meters (23 feet). They eat plankton and can weigh up to 2.3 tons (2.5 tons).

Southern elephant seal - The southern elephant seal is the biggest seal species and can weigh up to 4 tons (4.4 tons) in males. They're called "elephant seals" because the males have a long, trunk-like nose.

Leatherback sea turtle - The leatherback sea turtle is the largest sea turtle species and can weigh up to 916 kilograms (2,020 pounds). They're named for their leathery, rubbery shell. Leatherback sea turtles can grow up to 2 meters (6.6 feet) long.