Narwhals (Monodon monoceros) are a small to medium-sized whale that is easily recognized by its long, straight tusk. Found only in the Arctic, narwhals inhabit a circumpolar distribution throughout the Beaufort, Chukchi, and Barents Seas and adjacent areas of the Atlantic and Pacific oceans. Although often referred to as the “unicorn of the sea”, only male narwhals have tusks; females usually have two short teeth on their upper jaw. The purpose of the tusk is unknown, but it may be used for display or combat; recent research suggests that it may also be used to sense changes in water temperature and pressure. Narwhals are social animals and typically live in groups of 10-20 individuals; however, they can form larger herds during migration or when feeding. Herds are generally led by a single adult male, but multiple males may vie for dominance within a group.
Narwhals are predators and feed primarily on fish, squid, and shrimp. They use their large head and mouth to create suction that allows them to capture prey items near the ocean floor. To facilitate feeding at depths of up to 1 kilometer (0.6 mile), narwhals have evolved several adaptations, including high concentrations of myoglobin in their muscles (which allows them to store oxygen) and counter-current heat exchange between their arterial and venous blood vessels (which helps them regulate their body temperature).
Narwhals breed during the summer months; calves are born approximately 10-12 months later. Mating behavior has not been well studied in this species, but appears to be similar to that of other cetaceans. After a period of gestation lasting about 14-16 months, a single calf is born weighing 200-300 kilograms (440-660 pounds). The calf remains with its mother for 18-24 months before becoming independent; sexual maturity is reached at 5-10 years old. Females give birth every 3-5 years; males do not participate in parenting duties beyond protecting calves from predators such as polar bears or killer whales.
The primary threat to narwhal populations is humans – both through direct hunting pressure and indirect impacts such as climate change. Historically hunted for their meat, oil, bones ,and ivory tusks ,narwhals were particularly vulnerable due to their slow swimming speed and lack of fear towards humans . However ,the International Whaling Commission banned commercial hunting of narwhals in 1973 ,and today most hunting efforts target Inuit subsistence needs . Nevertheless ,illegal hunting still occurs ;a 2016 study estimated that over 1000 narwhals were illegally killed each year . Climate change also poses significant risks to narwal populations ;as Arctic sea ice melts ,new shipping routes open up which increase the likelihood of ship strikes , while changing ocean conditions make it more difficult for narwales find food . Additionally , pollutants such as mercury accumulate in ice floes which are then ingested by marine mammals like narwales when they feed on organisms living under the ice . These chemicals can cause neurological damage or death .