Narwhal

he narwhal and the beluga are the only two species in the family Monodontidae, a suborder of toothedwhales. These two species inhabit arctic and subarctic regions and have a circumpolar distribution, meaning they are found all around the North Pole. Being closely related, belugas and narwhals share certain characteristic traits such as the absence of a dorsal fin on their back. Instead, they have a dorsal ridge, which may be an adaptation to life in cold water. In fact, in most cetaceans, the blubber-less dorsal fin is known to be used to evacuate heat. In Monodontidae species, the smaller and stronger dorsal ridge is believed to be used notably to break through the ice in order to reach the surface.

Measuring between 3.95 m and 5.5 m, adult narwhals are about the same size as belugas. Additionally, males feature a long protruding tooth, which can add up to 3 m!

As with belugas, narwhals’ colouring changes over time. The skin turns paler with age and the speckled spots on the back change over time.

Both belugas and narwhals are gregarious and highly social, meaning they are most often seen in groups. For these two species, females experience menopause and grandmothers are believed to play a role in caring for young and transferring knowledge.

Despite their similarities and overlapping ranges, narwhals and belugas are not typically seen together. Researcher Marianne Marcoux, narwhal specialist at Fisheries and Oceans Canada says: “I once observed a beluga swimming amongst a group of narwhals in Eclipse Sound (Translator’s note: now known as Tasiujaq).Belugas and narwhals have been seen together during their spring migration in Navy Board Inlet, but these encounters are believed to be of short duration. One of the few places in Canada where the respective ranges of narwhals and belugas overlap is in northwest Hudson Bay. Narwhals and belugas share the same waters, but don’t necessarily intermingle.” Thus, the two species are not frequently seen together.

C’est fort possible que le narval parvienne à comprendre les bélugas et à se faire comprendre. La chercheuse Valeria Vergara, affiliée à l’organisme Ocean Wise et collaboratrice du Groupe de recherche et d’éducation sur les mammifères marins (GREMM), est spécialiste de la communication chez les bélugas. «J’ai peu de doutes que les narvals et les bélugas puissent bien communiquer entre eux. Il n’y a qu’un seul article scientifique publié sur le sujet, et il indique que les cris de contact chez les narvals sont très similaires à ceux des bélugas. J’ai pu entendre les enregistrements pris par l’auteur de l’article Ari Shapiro et j’ai vraiment reconnu les similitudes», explique-t-elle.

It is quite possible that the narwhal will come to understand the belugas and to make itself understood. Researcher Valeria Vergara, affiliated with Ocean Wise and collaborator for the Group for Research and Education on Marine Mammals (GREMM), is an expert in beluga communication. “I have little doubt that narwhals and belugas can communicate well with each other. The only published paper about narwhal contact calls indicates that they produce very similar contact calls as belugas do. The author [Ari Shapiro] sent me audio clips of his two tagged narwhal, and I was able to verify by ear that at least their contact calls are very similar to the contact calls produced by belugas,” she explains.

Contact calls are an element of communication that are believed to be used to identify the individual producing the sound, much like when we introduce ourselves before speaking into a walkie-talkie.

Valeria Vergara adds, “I know from chatting with other researchers that work with recordings in areas that are frequented by both species that it is often difficult to tell both species apart acoustically. This is not surprising, given their close taxonomic relationship and the fact that they have evolved in similar environments.” Will marine mammal communication specialists in the St. Lawrence such as Valeria Vergara or Yvan Simard from Fisheries and Oceans Canada recognize the narwhal in the recordings made here? Stay tuned!

Narwhal photo-ID projects are rare. As part of a study carried out in the Arctic, researchers Marianne Marcoux (Fisheries and Oceans Canada) and Marie Auger-Méthé (Dalhousie University) relied on notches in the animals’ dorsal ridge to differentiate them. Indeed, the colour pattern in narwhals changes over the years – unlike blue whales, for example, whose speckled mosaics are permanent. However, the two researchers have not been able to identify the St. Lawrence narwhal amongst those featured in their catalogue.

No, it’s not a unicorn horn, but rather a tooth growing through the narwhal’s upper lip! The species’ scientific name, Monodon monoceros, can be translated as “one tooth, one horn”. Narwhals usually have just two teeth, one of which is twisted in shape and can grow up to 3 m long in adult males. Rarely, some narwhals will show both teeth protruding out of their lip, with one often being shorter than the other. This characteristic tooth or tusk is found in males and occasionally in females. At the Marine Mammal Interpretation Centre, visitors can observe and touch a narwhal tusk measuring 176 cm long and weighing nearly 7 kg.

“Our” narwhal still has a relatively small tusk, a sign that it has not yet reached sexual maturity. Nevertheless, its tusk has gotten longer since 2016 and continues to grow every year.

Assumptions vary and it is possible that it performs multiple functions. Analysis of narwhal teeth has shown that they contain millions of nerve endings, which might allow the animal to sense water pressure, salinity and temperature, or perhaps even to detect prey. In a very dark, often ice-covered environment, the tusk might therefore serve as a sort of “flashlight”, allowing the animal to locate holes in the pack ice where it can surface to breathe.

On one occasion in 2017, researchers were able to film narwhals stunning prey with their tusks. This behaviour had previously been reported by Inuit, but had never been documented. However, it is not known how common such a hunting technique might be.

The tusk may also be a highly valued attribute by females and thereby play a role in determining which males get to reproduce.

Marks and scars in males suggest that the tusk may also be used in sparring. However, no researcher has ever documented such fighting and even the Inuit do not seem to have ever witnessed such displays of combat. However, it should be noted that observations in the Arctic are complicated by ice and darkness for much of the year. Young males are often seen clashing tusks during the summer months. Is this their way of showing off their fighting spirit? A means of communication?

There are still many mysteries surrounding the famous tusk of this “unicorn of the sea”.

Indeed, a Danish research team was able to confirm in 2019 that at least one narwhal-beluga hybrid has lived to adulthood. Published in Scientific Reports, this study was even able to demonstrate–through an analysis of DNA taken from the skull–that the male offspring was born to a female narwhal and a male beluga.

The story behind this discovery begins in 1990, when a Danish scientist noticed a strange skull on the roof of an Inuk man’s home in western Greenland. The shape of the skull resembles that of a beluga or narwhal, but not the dentition. The teeth are more numerous than those of the narwhal but less than those of the beluga; further, they are more angled and some of them are twisted like the left canine of the narwhal. The Inuk held on to this skull, but during his subsistence hunt he observed two other individuals similar to the one the skull belonged to. According to the description provided to the researcher, the whale was grey, of adult size, and had no dorsal fin, pectorals similar to those of a beluga and a narwhal-like tail. The researcher takes the skull back to the Natural History Museum of Denmark at the University of Copenhagen, where it remains to this day. Then, in 2019, researchers finally have access to the technology they need to confirm the hybrid hypothesis. Using stable isotopes, they are also able to study the animal’s diet, which differs from that of narwhals and belugas in its region. Why so? Possibly because of its odd teeth, it was better able to search for prey on the seabed. Despite its singularity, the whale was able to survive to adulthood.

Let’s return to the St. Lawrence. Here, the narwhal present amongst the belugas is a male, unlike the aforementioned case in Greenland. Is hybridization possible in this direction? At the present time, the narwhal has probably not yet reached sexual maturity. This will occur around the age of 11 to 13 years, a few years later than in females. Will female belugas be interested in him then? Is he fertile? Will interbreeding be possible? To be continued!

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The status of the narwhal is considered to be “of concern” by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Accelerating climate change is disrupting their habitat and the distribution of their prey, in addition to increasing shipping traffic in a region that until quite recently was rather quiet. For the estimated 160,000 narwhals in Canada, mitigating climate change is essential to preserving the quality of their habitat.

On the other hand, even if the narwhal is not endangered in the St. Lawrence, “our” individual is currently being observed with belugas which, in turn, represent an endangered population. So, regardless of where you are in the Estuary, a minimum distance of 400 metres should be maintained with belugas and, in turn, the narwhal.