The narwhal, also known as a narwhale (''Monodon monoceros''), is a medium-sized

toothed whale The toothed whales (also called odontocetes, systematic name Odontoceti) are a parvorder of cetaceans that includes dolphins, porpoises, and all other whales possessing teeth, such as the beaked whales and sperm whales. Seventy-three species of ...

that possesses a large "

tusk Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with pigs and walruses, or, in the case of elephants, elongated incisors. Tusks share c ...

" from a protruding

canine tooth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however ...

. It lives year-round in the

Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...

waters around

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

and

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

. It is one of two living species of

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Monodontidae The cetacean family Monodontidae comprises two living whale species, the narwhal and the beluga whale and at least four extinct species, known from the fossil record. Beluga and Narwhal are native to coastal regions and pack ice around the Arctic ...

, along with the

beluga whale The beluga whale () (''Delphinapterus leucas'') is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus ''Delphinapterus''. It is also known as the whi ...

, and the only species in the genus ''Monodon''. The narwhal males are distinguished by a long, straight,

helical Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A t ...

, which is an elongated upper left canine. The narwhal was one of many species described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in his publication ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

'' in 1758. Like the beluga, narwhals are medium-sized whales. For both sexes, excluding the male's tusk, the total body size can range from ; the males are slightly larger than the females. The average weight of an adult narwhal is . At around 11 to 13 years old, the males become

sexually mature Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definiti ...

; females become sexually mature at about 5 to 8 years old. Narwhals do not have a

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

and their neck

vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...

are jointed like those of most other mammals, not fused as in

dolphin A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...

s and most whales. Found primarily in Canadian Arctic and Greenlandic and Russian waters, the narwhal is a uniquely specialised Arctic predator. In winter, it feeds on

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

prey, mostly

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish order (biology), order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the ...

, under dense

pack ice Drift ice, also called brash ice, is sea ice that is not attached to the shoreline or any other fixed object (shoals, grounded icebergs, etc.).Leppäranta, M. 2011. The Drift of Sea Ice. Berlin: Springer-Verlag. Unlike fast ice, which is "fasten ...

. During the summer, narwhals eat mostly

Arctic cod ''Arctogadus glacialis'', known also with ambiguous common names Arctic cod and polar cod, is an Arctic species of fish in the cod family Gadidae, related to the true cod (genus ''Gadus''). ''Arctogadus glacialis'' is found in icy water. They ...

and

Greenland halibut The Greenland halibut or Greenland turbot (''Reinhardtius hippoglossoides'') belongs to the family Pleuronectidae (the right-eye flounders), and is the only species of the genus ''Reinhardtius''. It is a predatory fish that mostly ranges at dept ...

, with other fish such as

polar cod ''Boreogadus saida'', known as the polar cod or as the Arctic cod, is a fish of the cod family Gadidae, related to the true cod (genus ''Gadus''). Another fish species for which both the common names Arctic cod and polar cod are used is ''Arct ...

making up the remainder of their diet. Each year, they migrate from bays into the ocean as summer comes. In the winter, the male narwhals occasionally dive up to in depth, with dives lasting up to 25 minutes. Narwhals, like most toothed whales, communicate with "clicks", "whistles" and "knocks". Narwhals can live up to 50 years and are often killed by suffocation after being trapped due to the formation of

sea ice Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oce ...

. Other causes of death, specifically among young whales, are starvation and predation by

orcas The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pat ...

. As previous estimates of the world narwhal population were below 50,000, narwhals are categorised by the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

(IUCN) as "nearly threatened". More recent estimates list higher populations (upwards of 170,000), thus lowering the status to "least concern". Narwhals have been harvested for hundreds of years by

Inuit Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally similar indigenous peoples inhabiting the Arctic and subarctic regions of Greenland, Labrador, Quebec, Nunavut, the Northwest Territories ...

in northern Canada and Greenland for

meat Meat is animal flesh that is eaten as food. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in the Neolithic Revolution allowed the domestication of animals such as chic ...

and

ivory Ivory is a hard, white material from the tusks (traditionally from elephants) and teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mammals is ...

and a regulated subsistence hunt continues.

Taxonomy and etymology

The narwhal was one of many species originally described by

in his landmark 1758 10th edition of ''Systema Naturae''. Its name is derived from the

Old Norse Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic languages, North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and t ...

word ''nár'', meaning "corpse", in reference to the animal's greyish, mottled

pigmentation A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

, like that of a drowned sailor and its summertime habit of lying still at or near the surface of the sea (called "logging"). The scientific name, ''Monodon monoceros'', is derived from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

: "one-tooth one-horn". The narwhal is most closely related to the beluga whale. Together, these two species comprise the only extant members of the family

, sometimes referred to as the "white whales". The Monodontidae are distinguished by their medium size (at around in length), pronounced

melon A melon is any of various plants of the family Cucurbitaceae with sweet, edible, and fleshy fruit. The word "melon" can refer to either the plant or specifically to the fruit. Botanically, a melon is a kind of berry, specifically a "pepo". The ...

s (round sensory organs), short snouts and the absence of a true dorsal fin. Although the narwhal and the beluga are classified as separate genera, with one species each, there is some evidence that they may, very rarely, interbreed. The complete skull of an anomalous whale was discovered in West Greenland circa 1990. It was described by marine zoologists as unlike any known species, but with features midway between a narwhal and a beluga, consistent with the hypothesis that the anomalous whale was a narwhal-beluga hybrid; in 2019, this was confirmed by DNA and isotopic analysis.Hybridization between two high Arctic cetaceans confirmed by genomic analysis
in ''Nature''; Mikkel Skovrind, Jose Alfredo Samaniego Castruita, James Haile, Eve C. Treadaway, Shyam Gopalakrishnan, Michael V. Westbury, Mads Peter Heide-Jørgensen, Paul Szpak & Eline D. Lorenzen; Scientific Reports; volume 9, Article number: 7729 (2019) The white whales,

s (Delphinidae) and porpoises (Phocoenidae) together comprise the superfamily

Delphinoidea Delphinoidea is the largest group of toothed whales with 66 genera in 6 families. The largest living member of the superfamily is the killer whale, which can reach 6 tons, while the smallest is the vaquita. Taxonomy Based on McGowen ''et al''., ...

, which are of likely

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

origin. Genetic evidence suggests the porpoises are more closely related to the white whales and that these two families constitute a separate

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

which diverged from the rest of Delphinoidea within the past 11 million years. Fossil evidence shows that ancient white whales lived in tropical waters. They may have migrated to Arctic and sub-Arctic waters in response to changes in the marine food chain during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58 Narwhals do not have a

, possibly an evolutionary adaptation to swimming easily under ice, to facilitate rolling, or to reduce surface area and heat loss. Instead narwhals possess a shallower dorsal ridge. Their neck

are jointed, like those of land mammals, instead of being fused together as in most whales, allowing a great range of neck flexibility. Both these characteristics are shared by the fellow

. The tail flukes of female narwhals have front edges that are swept back and those of males have front edges that are more concave and lack a sweep-back. This is thought to be an adaptation for reducing drag caused by the tusk.

Tusk

The most conspicuous characteristic of the male narwhal is a single long

, which is in fact a

that projects from the left side of the upper jaw, through the lip and forms a left-handed helical spiral. The tusk grows throughout life, reaching a length of about . It is hollow and weighs around . About one in 500 males has two tusks, occurring when the right canine also grows out through the lip. Only about 15 percent of females grow a tusk, which typically is smaller than a male tusk, with a less noticeable spiral. Collected in 1684, there is only one known case of a female growing a second tusk (image). Scientists have long speculated on the biological function of the tusk. Proposed functions include use of the tusk as a weapon, for opening breathing holes in sea ice, in feeding, as an acoustic organ and as a secondary sex character. The leading theory has long been that the narwhal tusk serves as a secondary sex character of males, for nonviolent assessment of hierarchical status on the basis of relative tusk size. However, detailed analysis reveals that the tusk is a highly

innervate A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the e ...

d sensory organ with millions of

nerve endings A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the e ...

connecting seawater stimuli in the external ocean environment with the brain. The rubbing of tusks together by male narwhals is thought to be a method of communicating information about characteristics of the water each has travelled through, rather than the previously assumed posturing display of aggressive male-to-male rivalry. In August 2016,

drone Drone most commonly refers to: * Drone (bee), a male bee, from an unfertilized egg * Unmanned aerial vehicle * Unmanned surface vehicle, watercraft * Unmanned underwater vehicle or underwater drone Drone, drones or The Drones may also refer to: ...

videos of narwhals surface-feeding in Tremblay Sound,

Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' ...

showed that the tusk was used to tap and stun small

, making them easier to catch for feeding. The tusk cannot serve a critical function for the animal's survival, as females — which generally do not have tusks — typically live longer than males. Therefore, the general scientific consensus is that the narwhal tusk is a sexual trait, much like the antlers of a stag, the mane of a lion, or the feathers of a peacock.

Vestigial teeth

The tusks are surrounded posteriorly, ventrally and laterally by several small

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

teeth which vary in morphology and histology. These teeth can sometimes be extruded from the bone, but mainly reside inside open

tooth socket Dental alveoli (singular ''alveolus'') are sockets in the jaws in which the roots of teeth are held in the alveolar process with the periodontal ligament. The lay term for dental alveoli is tooth sockets. A joint that connects the roots of the ...

s in the narwhal's snout alongside the tusks. The varied morphology and anatomy of small teeth indicate a path of evolutionary

obsolescence Obsolescence is the state of being which occurs when an object, service, or practice is no longer maintained or required even though it may still be in good working order. It usually happens when something that is more efficient or less risky r ...

, leaving the narwhal's mouth toothless.

Genome

A 2.3 GB

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

sequence has been assembled from multiple Illumina libraries. The genome consists of 37.9% repetitive elements and encodes 21,785

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

-coding

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

s (similar to many other

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s). The genome will help to place the narwhal both into the evolutionary context of other

s but also will help to understand the

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

and

embryonic development An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

of features such as the striking tusk and its

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

Distribution

The narwhal is found predominantly in the Atlantic and Russian areas of the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

. Individuals are commonly recorded in the

Canadian Arctic Archipelago The Arctic Archipelago, also known as the Canadian Arctic Archipelago, is an archipelago lying to the north of the Canadian continental mainland, excluding Greenland (an autonomous territory of Denmark). Situated in the northern extremity of No ...

, such as in the northern part of

Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...

Hudson Strait Hudson Strait (french: Détroit d'Hudson) links the Atlantic Ocean and Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador ...

Baffin Bay Baffin Bay ( Inuktitut: ''Saknirutiak Imanga''; kl, Avannaata Imaa; french: Baie de Baffin), located between Baffin Island and the west coast of Greenland, is defined by the International Hydrographic Organization as a marginal sea of the Arct ...

; off the east coast of Greenland; and in a strip running east from the northern end of Greenland round to eastern Russia ( 170° East). Land in this strip includes

Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...

Franz Joseph Land , native_name = , image_name = Map of Franz Josef Land-en.svg , image_caption = Map of Franz Josef Land , image_size = , map_image = Franz Josef Land location-en.svg , map_caption = Location of Franz Josef ...

and

Severnaya Zemlya Severnaya Zemlya (russian: link=no, Сéверная Земля́ (Northern Land), ) is a archipelago in the Russian high Arctic. It lies off Siberia's Taymyr Peninsula, separated from the mainland by the Vilkitsky Strait. This archipelago s ...

. The northernmost sightings of narwhal have occurred north of Franz Joseph Land, at about 85° North latitude.

Behaviour

Social

Narwhals normally congregate in groups of about five to ten and sometimes up to 20 individuals outside the summer. Groups may be "nurseries" with only females and young, or can contain only post-dispersal juveniles or adult males ("bulls"), but mixed groups can occur at any time of year. In the summer, several groups come together, forming larger aggregations which can contain from 500 to over 1000 individuals. At times, a bull narwhal may rub its tusk with another bull, a display known as "tusking" and thought to maintain social dominance hierarchies. However, this behaviour may exhibit tusk use as a sensory and communication organ for sharing information about water chemistry sensed in tusk microchannels.

Migration

Narwhals exhibit seasonal migrations, with a high fidelity of return to preferred, ice-free summering grounds, usually in shallow waters. In summer months, they move closer to coasts, often in pods of 10–100. In the winter, they move to offshore, deeper waters under thick pack ice, surfacing in narrow fissures in the sea ice, or

leads Lead is a chemical element with symbol Pb and atomic number 82. Lead or The Lead may also refer to: Animal handling * Leash, or lead * Lead (leg), the leg that advances most in a quadruped's cantering or galloping stride * Lead (tack), a lin ...

. As

spring Spring(s) may refer to: Common uses * Spring (season) Spring, also known as springtime, is one of the four temperate seasons, succeeding winter and preceding summer. There are various technical definitions of spring, but local usage of ...

comes, these leads open up into channels and the narwhals return to the coastal bays. Narwhals from Canada and West Greenland winter regularly in the pack ice of Davis Strait and Baffin Bay along the continental slope with less than 5% open water and high densities of Greenland halibut. Feeding in the winter accounts for a much larger portion of narwhal energy intake than in the summer.

Diet

Narwhals have a relatively restricted and specialized diet. Their prey is predominantly composed of

polar Polar may refer to: Geography Polar may refer to: * Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates * Polar climate, the c ...

and

cuttlefish Cuttlefish or cuttles are marine molluscs of the order Sepiida. They belong to the class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for control of ...

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

and armhook squid. Additional items found in stomachs have included

wolffish Anarhichadidae, the wolffishes, sea wolves or wolf eels, is a family of marine ray finned fishes belonging to the order Scorpaeniformes. These are predatory, eel shaped fishes which are native to the cold waters of the Arctic, North Pacific and ...

capelin The capelin or caplin (''Mallotus villosus'') is a small forage fish of the smelt family found in the North Atlantic, North Pacific and Arctic oceans. In summer, it grazes on dense swarms of plankton at the edge of the ice shelf. Larger capelin ...

skate Skate or Skates may refer to: Fish *Skate (fish), several genera of fish belonging to the family Rajidae * Pygmy skates, several genera of fish belonging to the family Gurgesiellidae * Smooth skates or leg skates, several genera of fish belongin ...

eggs and sometimes rocks, accidentally ingested when whales feed near the bottom. Due to the lack of well-developed

dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolo ...

in the mouth, narwhals are believed to feed by swimming towards prey until it is within close range and then sucking it with considerable force into the mouth. It is thought that the

beaked whale Beaked whales (systematic name Ziphiidae) are a family of cetaceans noted as being one of the least known groups of mammals because of their deep-sea habitat and apparent low abundance. Only three or four of the 24 species are reasonably well-k ...

s, which have similarly reduced dentition, also suck up their prey. The distinctive tusk is used to tap and stun small prey, facilitating a catch. Narwhals have a very intense summer feeding society. One study published in the

Canadian Journal of Zoology The ''Canadian Journal of Zoology'' is a peer-reviewed scientific journal that covers zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the ...

tested 73 narwhals of different age and gender to see what they ate. The individuals were from the

Pond Inlet Pond Inlet ( iu, Mittimatalik, lit=the place where Mittima is buried) is a small, predominantly Inuit community in the Qikiqtaaluk Region of Nunavut, Canada, located on northern Baffin Island. To the Inuit the name of the place "is and always ...

and had their stomach contents tested from June 1978 until September 1979. The study found in 1978 that the Arctic cod (''

Boreogadus saida ''Boreogadus saida'', known as the polar cod or as the Arctic cod, is a fish of the cod family Gadidae, related to the true cod (genus ''Gadus''). Another fish species for which both the common names Arctic cod and polar cod are used is ''Arct ...

'') made up about 51% of the diet of the narwhals, with the next most common animal being the Greenland halibut ('' Reinhardtius hippoglossoides''), consisting of 37% of the weight of their diet. A year later, the percentages of both animals in the diet of narwhals had changed. Arctic cod represented 57% and Greenland halibut 29% in 1979. The deep-water fish – halibut,

redfish Redfish is a common name for several species of fish. It is most commonly applied to certain deep-sea rockfish in the genus ''Sebastes'', red drum from the genus '' Sciaenops'' or the reef dwelling snappers in the genus '' Lutjanus''. It is also a ...

('' Sebastes marinus'') and polar cod (''

Arctogadus glacialis ''Arctogadus glacialis'', known also with ambiguous common names Arctic cod and polar cod, is an Arctic species of fish in the cod family Gadidae, related to the true cod (genus ''Gadus''). ''Arctogadus glacialis'' is found in icy water. They gr ...

'') – were found primarily in the diet of the males, which means that the narwhals can dive deeper than below sea level. The study found that the dietary needs of the narwhal did not differ among genders or ages.

Diving

When in their wintering waters, narwhals make some of the deepest dives recorded for a marine mammal, diving to at least over 15 times per day, with many dives reaching . Dives to these depths last around 25 minutes, including the time spent at the bottom and the transit down and back from the surface. Dive times can also vary in time and depth, based on local variation between environments, as well as seasonality. For example, in the Baffin Bay wintering grounds, narwhals farther south appear to be spending most of their time diving to deeper depths along the steep slopes of Baffin Bay, suggesting differences in habitat structure, prey availability, or innate adaptations between subpopulations. Curiously, whales in the deeper northern wintering ground have access to deeper depths, yet make shallower dives. Because vertical distribution of narwhal prey in the water column influences feeding behaviour and dive tactics, regional differences in the spatial and temporal patterns of prey density, as well as differences in prey assemblage, may be shaping winter foraging behaviour of narwhals.

Communication

As in most toothed whales, narwhals use sound to navigate and hunt for food. Narwhals primarily vocalise through "clicks", "whistles" and "knocks", created by air movement between chambers near the blow-hole. These sounds are reflected off the sloping front of the skull and focused by the animal's

, which can be controlled by musculature. Echolocation clicks are primarily produced for prey detection and for locating obstacles at short distances. It is possible that individual "bangs" are capable of disorienting or incapacitating prey, making them easier to hunt, but this has not been verified. They also emit tonal signals, such as whistles and pulsed calls, that are believed to have a communication function. The calls recorded from the same herd are more similar than calls from different herds, suggesting the possibility of group or individual-specific calls in narwhals. Narwhals may also adjust the duration and the pitch of their pulsed calls to maximise sound propagation in varying acoustic environments Other sounds produced by narwhals include trumpeting and squeaking door sounds. The narwhal vocal repertoire is similar to that of the closely related beluga, with comparable whistle frequency ranges, whistle duration and repetition rates of pulse calls, however beluga whistles may have a higher frequency range and more diversified whistle contours.

Breeding and early life

Females start bearing calves when six to eight years old. Adult narwhals mate in April or May when they are in the offshore pack ice.

Gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...

lasts for 14 months and calves are born between June and August the following year. As with most marine mammals, only a single young is born, averaging in length and white or light grey in colour. During summer population counts along different coastal inlets of

Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada and the fifth-largest island in the world. Its area is , slightly larger than Spain; its population was 13,039 as of the 2021 Canadia ...

, calf numbers varied from 0.05% to 5% of the total numbering from 10,000 to 35,000 narwhals, indicating that higher calf counts may reflect calving and nursery habitats in favourable inlets. Hybrids have been documented between the narwhal and beluga (specifically a beluga male and a narwhal female), as one, perhaps even as many as three, were killed and harvested during a sustenance hunt. Whether or not these hybrids could breed remains unknown. The unusual dentition seen in the single remaining skull indicates the hybrid hunted on the seabed, much as walruses do, indicating feeding habits different from those of either parent species. Newborn calves begin their lives with a thin layer of blubber which thickens as they nurse their mother's milk which is rich in fat. Calves are dependent on milk for around 20 months. This long lactation period gives calves time to learn skills needed for survival during maturation when they stay within two body lengths of the mother.

Lifespan and mortality

A polar bear (Ursus maritimus) scavenging a narwhal whale (Monodon monoceros) carcass - journal

Narwhals can live an average of 50 years, however research using aspartic acid racemization from the lens of the eyes suggests that narwhals can live to be as old as 115 ± 10 years and 84 ± 9 years for females and males, respectively Mortality often occurs when the narwhals suffocate after they fail to leave before the surface of the Arctic waters freeze over in the late autumn. As narwhals need to breathe, they drown if open water is no longer accessible and the ice is too thick for them to break through. Maximum

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cel ...

swimming distance between breathing holes in ice is less than which limits the use of foraging grounds and these holes must be at least wide to allow an adult whale to breathe. The last major entrapment events occurred when there was little to no wind. Entrapment can affect as many as 600 individuals, most occurring in narwhal wintering areas such as Disko Bay. In the largest entrapment in 1915 in

West Greenland Kitaa, originally Vestgrønland ("West Greenland"), is a former administrative division of Greenland. It was by far the most populated of the divisions, being home to almost 90% of the total population. The divisions were de facto replaced by st ...

, over 1,000 narwhals were trapped under the ice. Despite the decreases in sea ice cover, there were several large cases of sea ice entrapment in 2008–2010 in the winter close to known summering grounds, two of which were locations where there had been no previous cases documented. This suggests later departure dates from summering grounds. Sites surrounding Greenland experience

advection In the field of physics, engineering, and earth sciences, advection is the transport of a substance or quantity by bulk motion of a fluid. The properties of that substance are carried with it. Generally the majority of the advected substance is al ...

(moving) of sea ice from surrounding regions by wind and currents, increasing the variability of sea ice concentration. Due to strong site fidelity, changes in weather and ice conditions are not always associated with narwhal movement toward open water. More information is needed to determine the vulnerability of narwhals to sea ice changes. Narwhals can also die of starvation.

Predation and hunting

Major predators are

polar bears The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...

, which attack at breathing holes mainly for young narwhals and

Greenland shark The Greenland shark (''Somniosus microcephalus''), also known as the gurry shark, grey shark, or by the Kalaallisut name ''eqalussuaq'', is a large shark of the family Somniosidae ("sleeper sharks"), closely related to the Pacific and souther ...

Killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus ''Orcinus'' and is recognizable by its black-and-white pa ...

s (orcas) group together to overwhelm narwhal pods in the shallow water of enclosed bays, in one case killing dozens of narwhals in a single attack. To escape predators such as orcas, narwhals may use prolonged submergence to hide under ice floes rather than relying on speed. Belugas+Narwhals

Humans hunt narwhals, often selling commercially the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

, carved vertebrae, teeth and tusk, while eating the meat, or feeding it to dogs. About 1,000 narwhals per year are killed, 600 in Canada and 400 in Greenland. Canadian harvests were steady at this level in the 1970s, dropped to 300–400 per year in the late 1980s and 1990s and rose again since 1999. Greenland harvested more, 700–900 per year, in the 1980s and 1990s. Tusks are sold with or without carving in Canada and Greenland. An average of one or two vertebrae and one or two teeth per narwhal are carved and sold. In Greenland the skin (

muktuk Muktuk (transliterated in various ways, see below) is a traditional food of the peoples of the Arctic, consisting of whale skin and blubber. It is most often made from the bowhead whale, although the beluga and the narwhal are also used. It is ...

) is sold commercially to fish factories, and in Canada to other communities. One estimate of the annual gross value received from narwhal hunts in

in 2013 was for 81 narwhals, or per narwhal. However the net income, after subtracting costs in time and equipment, was a loss of per person. Hunts receive subsidies, but they continue as a tradition, rather than for the money and the economic analysis noted that whale watching may be an alternate revenue source. Of the gross income, was for skin and meat, to replace beef, pork and chickens which would otherwise be bought, was received for tusks and carved vertebrae and teeth of males and was received for carved vertebrae and teeth of females.

Conservation issues

Narwhals are one of many mammals that are being threatened by human actions. Estimates of the world population of narwhals range from around 50,000 (from 1996) to around 170,000 (compilation of various sub-population estimates from the years 2000–2017). They are considered to be near threatened 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. Narwhals are difficult to keep in captivity. Narwhal satellite

are able to

hunt Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/ hide, bone/tusks, horn/antler, e ...

this whale species legally, as discussed above in Predation and hunting. Narwhals have been extensively hunted the same way as other sea mammals, such as

seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...

and whales, for their large quantities of fat. Almost all parts of the narwhal, meat,

, blubber and organs are consumed. ''

Muktuk Muktuk (transliterated in various ways, see below) is a traditional food of the peoples of the Arctic, consisting of whale skin and blubber. It is most often made from the bowhead whale, although the beluga and the narwhal are also used. It is ...

'', the name for raw skin and blubber, is considered a delicacy. One or two vertebrae per animal are used for tools and art. The skin is an important source of

vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...

which is otherwise difficult to obtain. In some places in Greenland, such as

Qaanaaq Qaanaaq (), formerly known as Thule or New Thule, is the main town in the northern part of the Avannaata municipality in northwestern Greenland. It is one of the northernmost cities and towns, northernmost towns in the world. The inhabitants of ...

, traditional hunting methods are used and whales are harpooned from handmade

kayaks A kayak is a small, narrow watercraft which is typically propelled by means of a double-bladed paddle. The word kayak originates from the Greenlandic word '' qajaq'' (). The traditional kayak has a covered deck and one or more cockpits, each s ...

. In other parts of Greenland and Northern Canada, high-speed

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats. Small boats are typically found on inl ...

s and

hunting rifle A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with bo ...

s are used. During growth, the narwhal accumulates metals in its internal organs. One study found that many metals are low in concentration in the blubber of narwhals and high in the liver and the kidney.

Zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

and

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

are found in higher densities in the kidney than the liver and

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

and

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

were found to be the opposite. Certain metals were correlated with size and sex. During growth, it was found that mercury accumulated in the liver, kidney, muscle and blubber and that cadmium settled in the blubber. Narwhals are one of the most vulnerable Arctic marine mammals to

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

due to altering sea ice coverage in their environment, especially in their northern wintering grounds such as the Baffin Bay and

Davis Strait Davis Strait is a northern arm of the Atlantic Ocean that lies north of the Labrador Sea. It lies between mid-western Greenland and Baffin Island in Nunavut, Canada. To the north is Baffin Bay. The strait was named for the English explorer Jo ...

regions. Satellite data collected from these areas shows the amount of sea ice has been markedly reduced. Narwhals' ranges for foraging are believed to be patterns developed early in their life which increase their ability to gain necessary food resources during winter. This strategy focuses on strong site fidelity rather than individual level responses to local prey distribution and this results in focal foraging areas during the winter. As such, despite changing conditions, narwhals will continue returning to the same areas during migration. Despite its vulnerability to sea ice change, the narwhal has some flexibility when it comes to sea ice and habitat selection. It evolved in the late Pliocene and so is moderately accustomed to periods of glaciation and environmental variability. An indirect danger for narwhals associated with changes in sea ice is the increased exposure in open water. In 2002 there was an increase in narwhal catches by hunters in

Siorapaluk Siorapaluk (West Greenlandic) or Hiurapaluk ( Polar Inuit) is a settlement in the Qaanaaq area of the Avannaata municipality in northern Greenland. It is one of the world's northernmost inhabited settlements, the northernmost settlement inhabite ...

that did not appear to be associated with increased effort, implying that climate change may be making the narwhal more vulnerable to harvesting. Scientists urge assessment of population numbers with the assignment of sustainable

quotas Quota may refer to: Economics * Import quota, a trade restriction on the quantity of goods imported into a country * Market Sharing Quota, an economic system used in Canadian agriculture * Milk quota, a quota on milk production in Europe * Indi ...

for stocks and the collaboration of management agreements to ensure local acceptance. Seismic surveys associated with oil exploration have also disrupted normal migration patterns which may also be associated with increased sea ice entrapment.

Cultural depictions

In legend

In Inuit legend, the narwhal's tusk was created when a woman with a

harpoon A harpoon is a long spear-like instrument and tool used in fishing, whaling, seal hunting, sealing, and other marine hunting to catch and injure large fish or marine mammals such as seals and whales. It accomplishes this task by impaling the t ...

rope tied around her waist was dragged into the ocean after the harpoon had struck a large narwhal. She was transformed into a narwhal and her hair, which she was wearing in a twisted knot, became the characteristic spiral narwhal tusk. Some

medieval In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the Post-classical, post-classical period of World history (field), global history. It began with t ...

Europeans believed narwhal tusks to be the horns from the legendary

unicorn The unicorn is a legendary creature that has been described since antiquity as a beast with a single large, pointed, spiraling horn projecting from its forehead. In European literature and art, the unicorn has for the last thousand years o ...

.Daston, Lorraine and Park, Katharine (2001). ''Wonders and the Order of Nature, 1150–1750''. New York: Zone Books, . As these horns were considered to have

magic Magic or Magick most commonly refers to: * Magic (supernatural), beliefs and actions employed to influence supernatural beings and forces * Ceremonial magic, encompasses a wide variety of rituals of magic * Magical thinking, the belief that unrela ...

powers, such as neutralising poison and curing

melancholia Melancholia or melancholy (from el, µέλαινα χολή ',Burton, Bk. I, p. 147 meaning black bile) is a concept found throughout ancient, medieval and premodern medicine in Europe that describes a condition characterized by markedly d ...

Vikings Vikings ; non, víkingr is the modern name given to seafaring people originally from Scandinavia (present-day Denmark, Norway and Sweden), who from the late 8th to the late 11th centuries raided, pirated, traded and se ...

and other northern traders were able to sell them for many times their weight in

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

. The tusks were used to make cups that were thought to negate any poison that may have been slipped into the drink. A narwhal tusk exhibited at

Warwick Castle Warwick Castle is a medieval castle developed from a wooden fort, originally built by William the Conqueror during 1068. Warwick is the county town of Warwickshire, England, situated on a meander of the River Avon. The original wooden motte-an ...

is according to legend the rib of the mythical Dun Cow. In 1555,

Olaus Magnus Olaus Magnus (October 1490 – 1 August 1557) was a Swedish writer, cartographer, and Catholic ecclesiastic. Biography Olaus Magnus (a Latin translation of his birth name Olof Månsson) was born in Linköping in October 1490. Like his elder ...

published a drawing of a fish-like creature with a horn on its forehead, correctly identifying it as a "Narwal". During the 16th century,

Queen Elizabeth I Elizabeth I (7 September 153324 March 1603) was Queen of England and Ireland from 17 November 1558 until her death in 1603. Elizabeth was the last of the five House of Tudor monarchs and is sometimes referred to as the "Virgin Queen". El ...

received a narwhal tusk worth 10,000

pounds sterling Sterling (abbreviation: stg; Other spelling styles, such as STG and Stg, are also seen. ISO 4217, ISO code: GBP) is the currency of the United Kingdom and nine of #Crown Dependencies and British Overseas Territories, its associated territori ...

—the 16th-century equivalent cost of a castle (approximately £1.5–2.5 million in 2007, using the

retail price index In the United Kingdom, the Retail Prices Index or Retail Price Index (RPI) is a measure of inflation published monthly by the Office for National Statistics. It measures the change in the cost of a representative sample of retail goods and servic ...

)–from

Sir Humphrey Gilbert Sir Humphrey Gilbert (c. 1539 – 9 September 1583) was an English people, English adventurer, explorer, Member of Parliament (United Kingdom), member of parliament and soldier who served during the reign of Elizabeth I of England, Queen ...

, who proposed that the tusk was from a "sea-unicorne". The tusks were staples of the cabinet of curiosities.

In literature and art

The narwhal was one of two possible explanations of the giant sea phenomenon written by

Jules Verne Jules Gabriel Verne (;''Longman Pronunciation Dictionary''. ; 8 February 1828 – 24 March 1905) was a French novelist, poet, and playwright. His collaboration with the publisher Pierre-Jules Hetzel led to the creation of the ''Voyages extraor ...

in his 1870 novel ''

Twenty Thousand Leagues Under the Sea ''Twenty Thousand Leagues Under the Seas'' (french: Vingt mille lieues sous les mers) is a classic science fiction adventure novel by French writer Jules Verne. The novel was originally serialized from March 1869 through June 1870 in Pierre-Ju ...

''. Verne thought that it would be unlikely that there was such a gigantic narwhal in existence. The size of the narwhal, or "unicorn of the sea", as found by Verne, would have been . For the narwhal to have caused the phenomenon, Verne stated that its size and strength would have to increase by five or ten times.

Herman Melville Herman Melville (Name change, born Melvill; August 1, 1819 – September 28, 1891) was an American people, American novelist, short story writer, and poet of the American Renaissance (literature), American Renaissance period. Among his bes ...

wrote a section on the narwhal (written as "narwhale") in his 1851 novel ''

Moby-Dick ''Moby-Dick; or, The Whale'' is an 1851 novel by American writer Herman Melville. The book is the sailor Ishmael (Moby-Dick), Ishmael's narrative of the obsessive quest of Captain Ahab, Ahab, captain of the whaler, whaling ship ''Pequod (Moby- ...

'', in which he claims a narwhal tusk hung for "a long period" in

Windsor Castle Windsor Castle is a royal residence at Windsor in the English county of Berkshire. It is strongly associated with the English and succeeding British royal family, and embodies almost a millennium of architectural history. The original cast ...

after Sir Martin Frobisher had given it to Queen Elizabeth. Another claim he made was that the Danish kings made their thrones from narwhal tusks.

References

External links

*

Narwhal Discoveries

{{Authority control Mammals described in 1758 Cetaceans of the Arctic Ocean Mammals of Canada Mammals of Greenland Mammals of Russia Monodontidae Articles containing video clips Unicorns Taxa named by Carl Linnaeus Holarctic fauna