Step 1 : Introduction to the question "What animal is known as "the unicorn of the sea"?"
...Thanks to its unique singular tusk, the narwhal is known as the "unicorn of the sea." Made of ivory, the massive tusk extends like a spiral up to over eight feet long and strongly resembles that of a mythical unicorn. These massive tusks are only found among male narwhals, although females may occasionally grow a smaller one. Narwhals are mysterious animals and not much is known about them, but scientists believe their tusks are used to impress females. Most closely related to orcas and belugas, narwhals are part of the porpoise family. They tend to swim in groups known as pods and occasionally massive gatherings of thousands of specimens have been sighted. They live in the extreme climate of the Arctic Circle and feed primarily on small fish and shrimp.