Narwhal: who he is and how he lives

Narwhal: who he is and how he lives

NARWHAL

SCIENTIFIC CLASSIFICATION

Kingdom

:

Animalia

Phylum

:

Chordata

Subphylum

:

Vertebrata

Class

:

Mammalia

Order

:

Cetacea

Suborder

:

Odontoceti

Family

:

Monodontidae

Kind

:

Monodon

Species

:

Monodon monoceros

Common name

: narwhal

GENERAL DATA

  • Body length: 4 - 4.7 m (excluding the horn of about 3 m)
  • Weight: 1000 - 1600 kg
  • Lifespan: 50 years in nature
  • Sexual maturity: female: at 4 m in length and weighing around 900 kg (4-7 years of age); male: at 4.7 m in length and weighing around 1600 kg (4-7 years of age)

HABITAT AND GEOGRAPHICAL DISTRIBUTION

The narwhal, scientific name Monodon monoceros together with the beluga it is the second representative of the Monodontidae family. It is the cetacean that lives further north, between 70 ° N and 80 ° N, therefore in the Arctic Ocean, near the polar ice pack from which it rarely moves away.

Narwhals prefer to stay in deep, very salty waters. During the summer period for about two months, they move to the southern bays and fjords where they find deep water. The world's largest population of narwhals lives in the arctic areas of Canada and northwestern Greenland.

PHYSICAL CHARACTERISTICS

The body of the narwhal is whitish in color studded with numerous dark spots on the back and a little lighter on the belly.

The head is relatively small in relation to the rest of the body and does not have the beaked snout, typical of odontocetes, but flattened.

The peculiarity of this large cetacean is the marked sexual dimorphism: they have only two teeth on the jaw of which only in the male (it is very rare in the female), that of the left arch is continuously growing, forward and with a left-handed spiral trend. enough to take the shape of a horn.

This horn in the narwhal can reach 3 m in length and a weight of 10 kg. It has a smooth appearance in the distal part while for the rest it takes on various colors depending on the type of algae from which it is colonized. It is formed by an outer layer of cement, an innermost layer of dentin and is crossed by numerous cavities in which blood flows. If damaged, the horn is repaired as the dentin is continuously growing. The rest of the teeth grow normally, only a few centimeters. Recent studies have shown that the horn is very rich in sensory receptors that connect, through nerve fibers, to the pulp of the tooth and from this to the brain. This discovery was very important as it highlights that through the horn the narwhal can have information on the salinity of the water (to which it is particularly sensitive), on the temperature and on the pressure (very important as it is one of the cetacean that goes very deep ).

The narwhal does not have a dorsal fin but only a small irregular crest of about 5 cm in height.

Considering that they are animals that live in the arctic regions, about a third of their weight is made up of fat.

CHARACTER, BEHAVIOR AND SOCIAL LIFE

The narwhal is an animal that lives in groups usually formed by a few individuals, 6 - 20 at the most, which however become thousands during seasonal migrations. The groups are generally uniform by sex and age group: adult males, females with their young, juveniles.

The narwhal is an animal that tends to stay close to the ice pack throughout the year and emerges from the ice through holes or openings to breathe.

They are deep-sea cetaceans, managing to dive beyond 1000 m (the other cetacean that goes so deep is the sperm whale).

The fact that the male is provided with the horn and the female does not, suggests that the males use it in fights for the right to mate: narwhals have in fact been sighted with broken horns or with pieces of horn in the flesh. At the same time, however, narwhals were seen rubbing their horns together without any aggressive attitude. Other scientists hypothesize that the horn could be used to move sediments from the seabed in search of food, a hypothesis not universally accepted because the females do not have it. Therefore, not finding a valid explanation for this very large dental extension, scientists are more in agreement in affirming that it is simply a secondary sexual character, without any practical importance.

All the attempts made to have these animals live in captivity have been a total failure: after 1-4 months they all died. It is thought that perhaps it is due to the fact that the type of structures necessary to accommodate them should be as large as that necessary to accommodate a whale being long, including the horn over 7 m.

EATING HABITS

The narwhal feeds on fish (cod, salmon, herring), cephalopods (octopus, squid) and crustaceans which it also looks for in deep waters. Since the animal is nearly toothless, it is thought to use suction to catch fish which are then swallowed whole.

REPRODUCTION AND GROWTH OF CHILDREN

In fact, the narwhal is not a particularly studied animal for which the methods of reproduction are not known precisely. It has been seen that to mate both the male and the female are arranged vertically, belly to belly and in that position there is copulation.

Mating takes place between March - May with a pregnancy that lasts about 15 months, therefore the young are born between July-August of the following year.


Usually only one puppy is born but twin births are not uncommon. The baby is 1.5 m long at birth and weighs about 80 kg and is darker than the parents.

It is not known exactly how long breastfeeding lasts but it is thought to be similar to that of beluga: 1.5 - 2 years of age.

The interval between births is approximately 3 years

PREDATION

The narwhal, apart from man, does not have many natural enemies: killer whales, more rarely polar bears and occasionally Greenland sharks and walruses.

Another cause of death is represented by ice: it is not uncommon for a narwhal to be trapped in ice (in English there is a precise term for this situation, "savssat"). This phenomenon was observed in the winter of 1914-1915, when over 1,000 narwhals were found trapped in the ice (it can occur suddenly due to the change in the wind and a sudden drop in temperature).

STATE OF THE POPULATION

The narwhal is classified in the IUNC Red list (2009.1) among the animals close to the threat of extinction NEAR THREATENED (NT) having estimated a population of about 80,000 specimens.

The IUNC has assessed the narwhal close to the threat of extinction, as the intense hunting that is exercised against it from Greenland and Canada is of serious concern, especially due to the lack of reliable data on mortality.

Canada and Greenland hunt these creatures to obtain ivory from the horn and for the meat and fat that form typical dishes, such as mattak (photo on the side). Even if both Cananda and Greenland have quoted the killings, it still seems that these limits are too high (in 2004 they were equal to 300 individuals) not to cause concern worldwide.

At one time the narwhal was heavily hunted by the Inuit populations for its skin, for the fat, for the meat (with which they fed the dogs) and also for the horn, used to make ornamental objects. In medieval times its horn was identified with that of the unicorn and for this reason it was hunted to obtain magical or therapeutic jewelry. Still today, however, it feeds illegal traffic as it is unfortunately sought after by many tourists.

Other threats to their population are posed by climate change that changes their habitat. In fact, the narwhal is among the Arctic mammals the most sensitive to climate changes due to its limited geographical distribution and therefore to its limited habitat and its highly specialized diet.

The species is listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Fauna and Flora, known simply as the "Washington Convention") which includes species not necessarily threatened with extinction, but whose trade must be controlled in order to avoid exploitation incompatible with their survival. It is also listed in Appendix II of the CMS (Convention on Migratory Species).

The European Union has instituted an absolute ban on the import of horns (active since December 2004) throughout the territory of the Union.

CURIOSITY AND DRAMATICITY

By chance, while surfing the net, I happened to find sites that provide tourist information on different countries of the world. Under the heading "Cuisine", in relation to the Greenland advertisement, I found the following writings: «The Greenlandic national dish is suaasat, boiled seal meat with rice and onions. Another specialty is mattak, whale skin with a thin layer of fat, eaten raw cut into squares. For our palates, the version of grilled mattak is probably tastier, roasted with a side of browned onions or boiled potatoes (...) ».

I wonder: why are these things emphasized instead of clearly denouncing that these countries offer food for protected and endangered animals and that because of them these biodiversity will surely be lost? Why not say how things are, clearly, and then leave it to everyone's conscience whether or not to eat that meat and whether to continue to include those countries in the itinerary of their holidays?


Video: Im a Narwhal. Read Aloud Flip-Along Book