A Brief Introduction to Narwhals
Narwhal Statistics
Weight
Females weigh 1000 kg at maturity
Males weigh 1600 kg at maturity
Length
At birth: 160 cm
Females: 360 cm at sexual maturity
Males: 420 cm at sexual maturity
Females: 400 cm at physical maturity
Males: 475 cm at physical maturity
Color
Infant narwhal are grey or grayish brown. After two years, the skin becomes more mottled with overlapping white patches. The grey color becomes more blackened. Adults are white on the dorsum (belly side) and white and mottled on the ventral side. Older adults have only a narrow dark triangular band, extending from the back of the neck at its widest portion to a point ending on the midline of the back.
Age Determination
There is currently no reliable method for determining the age of narwhal.
Gestation Period
Estimated at approximately 14 months.
Distribution
Atlantic portion of the Arctic Ocean. Concentrating in the Canadian High Arctic, Baffin Bay, Davis Straight and northern Hudson Bay. Also found in smaller numbers in the Greenland Sea extending to Svalbard to Severnaya Zemlya off Russia.
Vocalizations
Wide variation of clicks and whistles. Click amplitudes range from 19 kHz to 48 kHz. Click rates vary from 3-150 clicks/sec. Whistle amplitudes range from 300 Hz to 18 kHz.
Migration Patterns
Satellite tracking of narwhal reveal patterns that are both useful for government agencies and scientists to discover more information about ranges of migration and for insight into social behavior with various populations from Canada and Greenland.
Diving Behavior
Narwhals commonly dive to 1600 feet, though they can dive in excess of 3300 feet for more than a 20 minute period.
General Migration Pattern
During the winter months, narwhal live offshore near very heavy pack ice and move through leads and narrow channels during the spring ice melt.
Narwhal Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Monodontidae
Genus: Monodon Linnaeus, 1758
Species: M. monoceros
Binomial name: Monodon monoceros
Naming the Whale
Narwhal, Monodon monoceros, Qilalugaq qernartaq, are three descriptions of an artic whale characterized by its legendary tusk. Narwhal translates from Old Norse to mean “corpse-like,†describing the whale’s mottled black and white skin. Linneus documented the species name for the narwhal’s most unique feature, its unicorn-like single tusk found on most males. However, his naming of the whale in 1758 translates to mean “one tooth, one horn.†Narwhal have two teeth and no horns. The Inuit name translates to mean “the one that points to the sky,†describing the narwhal’s unique behavior of pointing the tusk straight upward out of the water.
The narwhal, or narwhale (Monodon monoceros), is a medium-sized toothed whale and possesses a large “tusk” from a protruding canine tooth. It lives year-round in the Arctic waters around Greenland, Canada, and Russia. It is one of two living species of whale in the Monodontidae family, along with the beluga whale. The narwhal males are distinguished by a long, straight, helical tusk, which is an elongated upper left canine. The narwhal was one of many species described by Carolus Linnaeus in his publication Systema Naturae 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 3.95 to 5.5 metres (13.0 to 18.0 feet); the males are slightly larger than the females. The average weight of an adult narwhal is 800 to 1,600 kilograms (1,800 to 3,500 pounds). At around 11 to 13 years old, the males become sexually mature; females become sexually mature at about 5 to 8 years old. Narwhals do not have a dorsal fin, and their neck vertebrae are jointed like those of other mammals, not fused as in dolphins and most whales.
Found primarily in Canadian Arctic and Greenlandic and Russian waters, the narwhal is a uniquely specialized Arctic predator. In winter, it feeds on benthic prey, mostly flatfish, under dense pack ice. During the summer, narwhals mostly eat Arctic cod and Greenland halibut, with other fish such as polar cod 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 1,500 metres (4,900 feet) in depth, with dives lasting up to 25 minutes. Narwhals, like most toothed whales, communicate with “clicks”, “whistles”, and “knocks”.
Conservation Status
Narwhals can live up to 50 years old. They are often killed by suffocation when the sea ice freezes over. Another cause of fatality, specifically among young whales, is starvation. The current population of the narwhal is about 75,000, so narwhals qualify for Near Threatened under the criterion of the International Union for Conservation of Nature (IUCN). Narwhals have been harvested for over a thousand years by Inuit people in northern Canada and Greenland for meat and ivory, and a regulated subsistence hunt continues.
Narwhals are currently considered near-threatened by the IUCN Red List. Exact data is not known regarding the number of narwhals in the world. There are concerns with specific populations near the coasts of eastern Canada and Greenland due to intense hunting. Many of the areas inhabited by narwhals are also subject to drilling and mining, which produces waste that is dangerous to all animal populations.
Distribution of Narwhals
The Narwhal’s Tusk
The narwhal, Monodon monoceros, has long fascinated sea explorers, scientists and aristocracy. This arctic whale is characterized by a single spiraled tusk extending six to nine feet, emerging from the upper jaw and through the lips of adult males. Males have the characteristic left front tooth extending approximately 8 feet and variable depending on the whale and the age. The right tooth remains embedded in the skull and measures roughly one foot. Some females may exhibit a tusk, and in rare instances a male with two tusks has been observed.
Fetal narwhal initially develop six pairs of maxillary or upper teeth and two pairs of mandibular or lower teeth. Only one pair from the maxillary jaw develop and the others are vestigial. Tusk length, girth, morphology, wear and coloration are all quite variable. Male tusks are usually longer and have a wide variation in ridge morphology, often appearing as a gently wavelike form when looking down the horizontal axis. Female tusks are shorter, straighter, have a more regularly defined morphology, and do not collect as much proteinacious or algae on the surface, thus appearing whiter.
Often associated with the horn of the unicorn, the narwhal tooth has found its way into the books of scientific rarities and mythical tales, and has inspired legend and lore. So prized was the fabled tooth of the unicorn that in the 16th century Queen Elizabeth paid 10,000 pounds — equivalent to the cost of an entire castle — for one. The tooth is revered by many cultures around the world. In Japan two crossed narwhal teeth adorn the entrance to the Korninkaku Palace, and in Denmark multiple teeth comprise the frame. The royal scepter in England is made from the rare tusk.
Narwhal Anatomy
Narwhal tusks, although well described and characterized within publications, are clouded by contradictory references, which refer to them as both incisors and canines. Males have the characteristic left canine tooth extending approximately 2.4 meters, variable depending on the whale and the age. The right tooth – which remains embedded in the skull – measures roughly 30.5 cm. Fetal narwhal initially develop six pairs of maxillary (or upper) teeth, and two pairs of mandibular (or lower) teeth. Only one pair from the maxillary jaw develop; the others are vestigial. Vestigial teeth are thought to have no functional use and on a pathway of evolutionary obsolescence.
Tusk length, girth, morphology, wear and coloration are all quite variable. Male tusks are usually longer and have a wide variation in ridge morphology, often appearing gently wave-like when looking down the horizontal axis. Female tusks are shorter, straighter, have a more regularly defined morphology, and do not collect as much proteinaceous or algae on the surface, thus appearing whiter. The tusk is hollow during early growth and calcifies with age. An average male tusk weighs 10 kg (22 lb). About one in 500 males has two tusks.
Narwhal Genetics
Since the narwhal has not been sequenced, a query of keywords “tooth†and “nerve†for the Tursiops truncatus genome was performed using the Ensembl database. The following genes – NGFR, DLX2, TFAP2A and GLI3 – were the only genes that resulted from the search. Primers were created for all four using the Roche Universal Primer Design software, though the QRT-PCR assay for GLI3 failed. Another approach to identifying additional sensory genes was based on the human genome; FAM134B and WNK1 (formerly HSN2) genes have been shown to be involved in hereditary sensory neuropathy type II, which has a pathology for the reduction or loss of the sensory perception of pain, temperature and touch (Kurth 2010). These genes were cross-referenced to the Tursiops truncatus genome, and to our surprise, based on the Ensembl database search, there was a sequence similarity for these two genes
The sensory and housekeeping genes were designed based on the Tursiops truncatus and Stenella coeruleoalba genomes, respectively. The Ensembl database (uswest.ensembl.org) was utilized to project transcripts involved in sensory nerve functions by using the closest relative of the narwhal whose genome had been sequenced (Tursiops truncates [Database version: 71.1]) (Hubbard et al., 2002; Flicek et al., 2012). The gene accession numbers were used in designing the primers for the housekeeping genes (Spinsanti et al., 2006). The Roche Universal ProbeLibrary probes and target-specific PCR primers were selected using the ProbeFinder Assay Design software (Rozen and Skaletsky, 2002; Kuo et al., 2006).
Fascinating Facts on the Narwhals
1. Its tusk is actually a tooth
While it might appear to be situated in the center of its head, the narwhal’s tusk is actually an exaggerated front left tooth that protrudes from the upper lip. The right front tooth is small, and usually remains in the mouth. Stranger still, while most teeth (including human teeth) have a hard exterior and a soft, sensitive interior, narwhal teeth are the opposite. “No big surprise. It’s been opposite in every other way,†Martin Nweeia, a clinical instructor at the Harvard School of Dental Medicine, told NPR after making this discovery. “But to find a tooth that is soft on the outside and has its most dense part around the pulp was completely odd.â€
2. The tusk can grow to be 10 feet long
Narwhal tusks grow throughout the animals’ entire lives and can reach incredible lengths. While the tusk as a whole is straight—the only straight tusk we know of, in fact—a closer look reveals that as it grows, it spirals to the left.
3. The tusk can bend about a foot before breaking
Its tough core and soft outer layer result in a tusk that is both strong and flexible. It can bend significantly without cracking, which is important for a tusk as long as the narwhal’s.
4. We’re not entirely sure what it’s for
History has numerous explanations for the narwhal’s massive tusk. One theory is that it can be used as a weapon, though this claim lacks sufficient evidence. Another suggests it is an accessory for finding mates and asserting dominance, much like peacock feathers or deer antlers. But the most recent theory, produced by Nweeia and his team, suggests it acts as a sort of environmental sensor. According Nweeia’s research, the tusk is porous and full of nerves, taking in external stimuli like water pressure, temperature, and salinity, and sending information back to the brain. To test this theory, Nweeia fitted narwhals with a kind of “jacket†that insulated the tusk from environmental factors. Then, researchers pumped the jacket full of water samples of varying salinity levels to mimic different kinds of sea ice. They found that different levels of salinity caused the narwhals’ heart rates to fluctuate, indicating they could sense the change and had a physical reaction to it. “But regardless of the reason, the results suggest that narwhals can funnel water into their tusks to measure its salt concentration,†Nweeia said.
5. Not all narwhals have tusks
In most tusked animals, the tusks appear in both males and females. However, in narwhals, only the males and about 15 percent of females have tusks. This is confusing to researchers. If indeed the narwhal tusk is a mechanism for sensing the environment, as recent studies suggest, why wouldn’t such an evolutionary trait be inherited by females as well? This perhaps lends more evidence to the theory that the tusk is mainly an accessory for garnering attention and establishing dominance among males.
Their skin is rich in vitamin C
In fact, there is roughly as much vitamin C in one ounce of narwhal skin as there is in one ounce of oranges. Narwhal skin is a primary source of vitamins for the Inuit people of the Arctic. According to the BBC, “without the narwhal it is doubtful whether the Inuit would have survived in some parts of the Arctic.â€
7. There are none in captivity (which is awesome)
Unlike their close relatives, beluga whales, narwhals do not thrive in captivity. In the ’60s and ’70s, several attempts at capturing and keeping narwhals resulted in all of the animals dying within several months. In fact, all narwhals kept in captivity have died. Some animals simply aren’t meant to be captured.
Narwhal Information Posters
Some More Detailed Information on the Narwhal
Taxonomy and etymology
The narwhal was one of the many species originally described by Linnaeus in his Systema Naturae. Its name is derived from the Old Norse word nár, meaning “corpse”, in reference to the animal’s greyish, mottled pigmentation, like that of a drowned sailor and its summer-time habit of lying still at or near the surface of the sea (called “logging”). The scientific name, Monodon monoceros, is derived from the Greek: “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 Monodontidae, sometimes referred to as the “white whales”. The Monodontidae are distinguished by medium size (at around 4 m (13 ft) in length), forehead melons (round sensory organs), short snouts, and the absence of a true dorsal fin. The white whales, dolphins (Delphinidae) and porpoises (Phocoenidae) together comprise the superfamily Delphinoidea, which are of likely monophyletic origin. Genetic evidence suggests the porpoises are more closely related to the white whales, and that these two families constitute a separate clade 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.
Description
Narwhals are medium-sized whales, and are around the same size as beluga whales. Total length in both sexes, excluding the tusk of the male, can range from 3.95 to 5.5 m (13 to 18 ft). Males, at an average length of 4.1 m (13 ft 5 in), are slightly larger than females, with an average length of 3.5 m (11 ft 6 in). Typical adult body weight ranges from 800 to 1,600 kg (1,800 to 3,500 lb). Male narwhals attain sexual maturity at 11 to 13 years of age, when they are about 3.9 m (12 ft 10 in) long. Females become sexually mature at a younger age, between 5 to 8 years old, when they are around 3.4 m (11 ft 2 in) long. The pigmentation of narwhals is a mottled pattern, with blackish-brown markings over a white background. They are darkest when born and become whiter with age; white patches develop on the navel and genital slit at sexual maturity. Old males may be almost pure white. Narwhals do not have a dorsal fin, possibly an evolutionary adaptation to swimming easily under ice. Their neck vertebrae are jointed, like those of land mammals, instead of being fused together as in most whales. Both these characteristics are shared by the beluga whale. 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.
Narwhal 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, usually 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. As spring 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.
Narwhal Diet
Narwhals have a relatively restricted and specialized diet. Their prey is predominantly composed of Greenland halibut, polar and Arctic cod, cuttlefish, shrimp and armhook squid. Additional items found in stomachs have included wolffish, capelin, skate eggs and sometimes rocks, accidentally ingested when whales feed near the bottom. Due to the lack of well-developed dentition 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 whales, which have similarly reduced dentition, also suck up their prey.
Narwhals have a very intense summer feeding society. One study published in the Canadian Journal of Zoology tested 73 narwhals of different age and gender to see what they ate. The individuals were from the Pond Inlet and had their stomach contents tested from June 1978 until September 1979. The study found in 1978 that the Arctic cod (Boreogadus saida) 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 (Sebastes marinus), and polar cod (Arctogadus glacialis) – are found in the diet of the males, which means that the narwhals can dive deeper than 500 m (1,600 ft) below sea level. The study found that the dietary needs of the narwhal did not differ among genders or ages.
Narwhal Communication
As with most toothed whales, narwhals use sound to navigate and hunt for food. “Clicks”, “whistles” and “knocks”, may be created via air between chambers near the blow-hole, and reflected off the sloping front of the skull. These sounds are then focused by the animal’s melon, which can be controlled by musculature. “Click trains” are produced both for echo-location of prey, 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. The whistles of a narwhal are rarely heard, especially compared to the beluga. Other sounds produced by narwhals include trumpeting and squeaking door sounds.
Narwhal Pictures
PDFs and documents on Narwhals
> Narwhal Communication and Grouping Behavior.
> Assessment of the Subsistence Harvest and Biology of Narwhals.
> Status Report on Narwhals.
> Research Article on Narwhals.
> Artic Sea Ice Trends and Narwhal Vulnerability.
> Social Behavior of Narwhals.
> Narwhals.
> Harvard Gazette – Marine Biology Mystery Solved :/
Narwhal Documentaries and videos
Todd McLeish on Narwhals — Aquarium Lecture Series
Uncovering the Mysteries of the Narwhal | Presentation
Narwhal Tooth
In the life of a Narwhal
In the life of a Narwhal
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