Narwhal: Unicorn of the Sea

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Narwhals live in groups of 10 to 20 individuals but in the summer they come together in groups a b c d e f g "The Narwhal: Unicorn of the Seas" (PDF). Fisheries and Oceans Canada. 2007 . Retrieved 10 July 2013. This article is republished from The Conversation under a Creative Commons license. Read the original article. Main article: Tusk This narwhal skull has rare double tusks. Usually, the canine tooth only on the left side of the upper jaw becomes a tusk. Rarely, males develop two tusks. This specimen, however, was of a female (Zoologisches Museum, Hamburg; collected in 1684)

The narwhal’s scientific name is Monodon monoceros, which means “one tooth, one horn” in Latin. This refers to the fact that narwhals are born with two canine teeth, one of which (in males) grows into a horn. Dives to the depths at which a narwhal goes typically last between 25 and 30 minutes, including the time spent at the bottom and the time spent ascending and descending. According to this, Narwhals can hold their breath for a minimum of 25 minutes.Males use the tusks to determine social status, dominance over other males, and compete for mating females. 6. Narwhals use their tusks to hunt for fish.

After a 15-month gestation period, pregnant females move to deep bays or inlets to give birth to their single calves, which are around 5 feet (1.5 m) long and 180 lbs. (82 kg) when born. The American Cetacean Society suggests that female narwhals give birth to one calf about every three years, and each calf stays with its mother for up to 20 months. Narwhals have a current estimated population of 45,000 to 80,000. Researchers at The Royal Society have concluded that by the end of this century, the world’s narwhal population will be drastically reduced due to rising water temperatures. 13. What Animals Prey On Narwhals? The myth of unicorn horns had circulated around Europe for centuries before his voyage, which faded as European experts become more familiar with the animals. 2 2. Both male & females are born with two small teeth embedded in their skulls, but only in males does the front left tooth grow into a spiral tusk. The most conspicuous characteristic of the male narwhal is a single long tusk, which is in fact a canine tooth [19] [20] 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 1.5 to 3.1m (4.9 to 10.2ft). It is hollow and weighs around 10kg (22lb). About one in 500 males has two tusks, occurring when the right canine also grows out through the lip. Only about 15 per cent of females grow a tusk, [21] which typically is smaller than a male tusk, with a less noticeable spiral. [22] [23] [24] There is only one known case of a female growing a second tusk; the specimen (right) was collected in 1684. [25]The International Union for Conservation of Nature (IUCN) considers the narwhal a species of least concern, meaning their population is not under significant threat. The IUCN estimates that there are about 123,000 mature individuals divided into 12 subpopulations within the Arctic. Even though narwhals have been known to stun fish with their tusks, they have never been reported to assault people. The tusk of the narwhal has also recently been shown to be a sensory organ capable of detecting changes in its environment and storing crucial ecological information. Powdered, the substance was used as an aphrodisiac, a medicine and a poison detector, reported another article from Smithsonian magazine. In their intact, spiraling form, narwhal tusks were carved into utensils, scepters, swords and more. At the height of its trade, Smithsonian wrote, narwhal tusk was worth ten times its weight in gold. Heide-Jørgensen, M. P.; Reeves, R. R. (July 1993). "Description of an Anomalous Monodontid Skull from West Greenland: A Possible Hybrid?". Marine Mammal Science. 9 (3): 258–268. doi: 10.1111/j.1748-7692.1993.tb00454.x.

A 2.3 GB genome sequence has been assembled from multiple Illumina libraries. The genome consists of 37.9% repetitive elements and encodes 21,785 protein-coding genes (similar to many other mammals). The genome will help to place the narwhal both into the evolutionary context of other whales but also will help to understand the evolution and embryonic development of features such as the tusk and its sexual dimorphism. [35] Distribution Narwhals in the Creswell Bay at Somerset Island 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. Narwhals are part of an Arctic environment that is rapidly changing. The region is warming twice as fast as the rest of the world – 1.35 degrees Fahrenheit (0.75 degrees Celsius) in the last decade alone. By comparison, it’s taken the Earth as a whole the past 137 years to warm by nearly the same amount, 0.8°C. The Narwhal tusk is a modified tooth in the upper left side of the jaw. Male narwhals commonly have a single tusk though a few may also have two tusks. Up to 2 per cent of females have an erupted tusk.

At times, a bull narwhal may rub its tusk with another bull, a display known as "tusking" [28] [36] and thought to maintain social dominance hierarchies. [36] However, this behaviour may exhibit tusk use as a sensory and communication organ for sharing information about water chemistry sensed in tusk microchannels. [27] [28] Migration Upon another small island here,” Frobisher wrote in his journal, “was also found a great dead fish, which, as it would seem, had been embayed with ice, and was in proportion round like to a porpoise, being about twelve foot long, and in bigness answerable, having a horn of two yards long growing out of the snout or nostrils. This horn is wreathed and straight, like in fashion to a taper made of wax, and may truly thought to be the sea-unicorn.” During winter months, male narwhals have been observed making some of the deepest dives ever recorded, with regular dives of at least 800 meters, between 10-25 times a day. These dives are virtually vertical, to maximise speed. The pressure at depths of over 800m can exceed 2200 PSI (150 atmospheres). 5 12. They have evolved to withstand incredible water pressure.

During growth, the narwhal accumulates metals in its internal organs. One study found that various metals are lightly concentrated in the blubber and densely concentrated in the liver and the kidneys. Zinc and cadmium are found in higher concentration in the kidney compared to the liver; the inverse is true for lead, copper and mercury. Certain metals were correlated with size and sex. During growth, it was found that mercury accumulated in the liver, kidney, musculature, and blubber, and cadmium also settled in the blubber. [60] The tusk is essentially unique to male narwhals. Very rarely, a female will grow a tusk, or even more rarely a male narwhal will grow two. Tusks exported from the Arctic, perhaps by the Vikings, reached Europe, the Mediterranean and even the Far East as early as the Middle Ages and became the source of the unicorn myth. The tusks were sold to the very rich without a good description of the animal from which they came and inspired a great deal of fantasy. A Danish coronation chair from the 1600s is made of narwhal tusks. Image via Richard Mortel/ Wikimedia,

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E. T. Newton. 1891. The vertebrata of the Pliocene deposits of Britain. Memoirs of the Geological Survey of the United Kingdom". Memoirs of the Geological Survey, Great Britain. 1891.