The narwhal (Monodon monoceros) is a deep-diving cetacean of the odontocete (‘toothed whales’) family which lives in the cold Arctic and sub-Arctic waters. An intriguing mammal also referred to as ‘unicorn’ of the sea, these whales and their unique tusks have given rise to myths. The long tusk of the male narwhal sets these whales apart.
An ongoing study to understand the structure and dynamics of narwhal populations in a changing climate hopes to conserve their populations and ensure they remain sustainable biological resources, according to a report in January 2020. In order to understand how narwhals may or may not adapt to the climate change in the Arctic, the study has tried to develop a basic understanding of their ecology.
About Narwhals
Narwhals are a significant cultural, economic and nutritional resource for native communities in cold places of the Arctic like Greenland and Canada. They’re highly adapted to living in areas almost completely covered with sea ice. Narwhals are among the only whales that live in areas with dense sea ice cover for up to six months each winter.
Narwhals usually travel in pods and can be quite sneaky—they pass through the water’s surface with only a small sliver of their mottled black and white skin showing above the water when they surface to breathe.
Unlike all other toothed whales, the narwhal has no teeth in its mouth. All narwhals have 2 canine teeth that can grow into tusks. The male has a long straight tusk, protruding 6 to 10 feet out of its upper left jaw. A long tusk on an adult male can be more than half the usual total body length of about 16 feet. This tooth does not curve but grows in a counter-clockwise spiral. Mostly, the left tooth grows into a long tusk through the upper lip of the animal. The right canine tooth, also a tusk, remains embedded in the skull unerupted. However, occasionally, both tusks erupt. Generally only one grows into a tusk but even if both do, they spiral to the left. The tusk grows in most males. Female narwhals have their tusks embedded and they erupt very rarely.
Use of Tusks
The animals use the tusks for various purposes—breaking ice, sword fighting with other whales, spearing or smacking fish for food, sensing temperatures or digging in the bottom the sea.
The tusk is considered as not very vital for the survival of the male narwhal. It is seen as a sexual trait, much like the antlers of a stag, the mane of a lion or the feathers of a peacock. The tusk may have a place in determining social rank and males competing for attention of females (for a female, it is a visual signal for mating). Male narwhals, like other animals, have been given the trait to visually size each other up as competitors, and here tusks show aggression and dominance. Tusks are related to their aggressive interactions.
During the summertime in the northern Arctic bays and fjords, male narwhals can be seen interacting at the surface: their tusks carefully crossing one another. Such behaviour might help adult males compare themselves and it may maintain dominance hierarchies. Or perhaps the young males who watch this instinctively acquire these skills necessary for performance of their adult roles.
Tusks exported from the Arctic, perhaps by the Vikings, reached Europe, the Mediterranean and even the Far East as early as the Middle Ages in earlier times.
There are more than 100,000 narwhals in the world which are divided into subpopulations of between a few thousand to up to 30,000 animals, based on where they are located in the summer—in ice-free bays and fjords or at glacial fronts. Narwhals’ extensive migrations depend on the formation and retreat of annual sea ice. Some animals can travel thousands of miles in the period of one year. In autumn, they migrate to areas that are deep, offshore and ice-covered, usually along the continental slope. Most feeding takes place in winter, and then females give birth once that season is over.
During the winter months in the dense pack ice, narwhals dive over a mile in depth, sometimes swimming upside down while descending into pitch black water. They sometimes find prey close to the bottom, such as Greenland halibut, and they swallow them whole.
The Arctic environment is fast 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 (in contrast, the Earth as a whole has warmed about the same amount, i.e., 0.8 degree in around 137 years). So the study of these animals, which are an intrinsic part of this environment, becomes important in the context of the climatic changes.