> Which sea whale has a long horn, or tusk, protruding from its head?And the answer: Narwhal.Photo credit: пресс-служба ПАО "Газпром нефть via Wikimedia Commons.Known asUnicorns of the Sea, Narwhals spend their lives in Arctic waters. The Narwhaltusk, found most commonly on males, is an enlarged tooth which grows in theshape of a spiral and can reach up to ten feet in length.Narwhals are unique among whale species. Its long, ivory tusk actually extendsfrom the upper side of its lower jaw, making it technically a very impressivetooth. But in case you were wondering— no, the Narwhal tusk is not simply theworld's sharpest incisor. The tusk is a 7-10 foot tooth is actually packed with10 million nerve endings. For this reason, scientists have recently come tobelieve that the tusk may be a sensory organ. Narwhals may use their tusks todetect temperature, water pressure, particle gradients, and motion. In addition,the tusk is flexible, capable of flexing about a foot in all directions.Like other marine mammals, Narwhals use echolocation — or "bio sonar" — tonavigate the frozen waters. Echolocation refer to a series of clicks emitted bythe Narwhal, which then reverberate off of their surroundings and allow them toform a reconstruction of their surroundings. Interestingly, recent researchsuggests that Narwhals are able to piece together small, detailed snapshots oftheir environment so effectively that they may be capable of the highestresolution reconstruction of any animal on Earth— with the possible exception ofthe beluga whale. Once the picture has been painted via echolocation, thenarwhals can fill in the details, such as the movement of prey or the scent of amate, using their long, porous tooth.Learn more about the Unicorn of the Sea here[https://travelnunavut.ca/10-fun-facts-about-narwhal-are-narwhal-endangered/].