Some organisms, such as bacteria, are hard to see, and therefore difficult to understand their role in the cycle. But whales are big creatures, and are seen in nature often. You have probably seen a whale before. You can see a whale, if you want to, by going to the ocean, and if you do not live by the ocean, you can see one by going to Sea World or other science learning institutions. Whales have sleek, streamlined bodies that move easily through the water.
Cetaceans are the group of mammals that includes the whales, dolphins, and porpoises.
These enormous animals eat about 4 tons of tiny krill each day, obtained by filter feeding through baleen. Adult blue whales have no predators except man. The blue whale is the largest animal that has ever existed on Earth. It is larger than any of the dinosaurs were. They are also the loudest animal l on Earth.