Narwhals are one of the many species of mammals that are threatened by human actions. [59] Estimates of the world population of narwhals range from around 50,000 (from 1996) [38] to around 170,000 (compilation of various sub-population estimates from the years 2000–2017). [4] They are considered to be near threatened [ inconsistent] and several sub-populations have evidence of decline. In an effort to support conservation, the European Union established an import ban on tusks in 2004 and lifted it in 2010. The United States has forbidden imports since 1972 under the Marine Mammal Protection Act. [59] Narwhals are difficult to keep in captivity. [28] Male narwhal captured and satellite tagged When he meets a jellyfish, they both assume they are imagining one another as neither of them has come across such bizarre-looking animaL before. Nevertheless, they decide to become friends and embark on some awesome adventures together. During the summertime in the northern Arctic bays and fjords, male narwhals can be seen interacting at the surface, carefully crossing their tusks and touching them together. Such behavior might help adult males compare themselves and maintain dominance hierarchies. Or perhaps it helps young males nearby learn skills necessary for performance in adult sexual roles. A pod of narwhals in Northwest Greenland. Image via Kristin Laidre. The narwhal was one of two possible explanations offered by Professor Pierre Aronnax in regards to the naval phenomena damaging ships in Jules Verne's 1870 novel Twenty Thousand Leagues Under the Sea; Aronnax comes to this conclusion by presuming that "we do know all the living species"; he was unwilling to speculate wildly to the American press. Verne writes: "The common narwhal or sea unicorn often attains a length of 18.3m (60ft)." For the narwhal to have caused the damage to the various vessels, Aronnax stated that its size and strength would have to increase by five or ten times; Monodon monoceros". Fisheries and Aquaculture Department: Species Fact Sheets. Food and Agriculture Organization of the United Nations. Archived from the original on 16 February 2012 . Retrieved 20 November 2007.

a b c Laidre, K (2004). "Deep-ocean predation by a high Arctic cetacean". ICES Journal of Marine Science. 61 (1): 430–440. doi: 10.1016/j.icesjms.2004.02.002. The notion of the tusk being a critical sensory organ, says Laidre, “remains a toothless theory with no supporting data.”a b Nweeia MT, etal. (2014). "Sensory ability in the narwhal tooth organ system". The Anatomical Record. 297 (4): 599–617. doi: 10.1002/ar.22886. PMID 24639076. S2CID 6028832.

These legendary animals have two teeth. In males, the more prominent tooth grows into a swordlike, spiral tusk up to 10 feet long. The ivory tusk tooth grows right through the narwhal's upper lip. Scientists are not certain of the tusk's purpose, but some believe it is prominent in mating rituals, perhaps used to impress females or to battle rival suitors. Females sometimes grow a small tusk of their own, but it does not become as prominent as the male's. Group travel Narwhals feed mainly on Greenland halibut, Arctic and polar cod, squid and shrimp. It appears that narwhals find their winter food supplies down towards the seafloor (down to 1 mile depths even!) and in the spring, find their food near the ice edge. a b c Laidre, K. L.; Stirling, I.; Lowry, L.; Wiig, Ø.; Heide-Jørgensen, M. P. & Ferguson, S. (2008). "Quantifying the sensitivity of arctic marine mammals to climate-induced habitat change". Ecological Applications. 18 (2): S97–S125. doi: 10.1890/06-0546.1. PMID 18494365. S2CID 23765771.Not much is known about the reproductive habits of narwhals, but we do know that females go through menopause and spend a significant amount of time in a post-reproductive phase. They also live for a long time, with the oldest individuals reaching up to 125 years.