Ecological Niche

Narwhals are amid the strangest and most resilient animals in the Arctic. In fact, many people do not believe narwhals exist. A narwhal has the body of a dolphin/whale hybrid, and the “horn” of the fictitious unicorn. This “horn,” which is a tooth, adds to the tales of fantasy surrounding the Narwhal and its origins.

Narwhals live, hunt, and reproduce underwater, where they swim in search of prey in pods. Each pod ranges from 2-3 narwhals to several hundred narwhals. Narwhals spend their days in their wintering grounds diving. Narwhals typically dive to at least 800 meters between 18 and 25 times per day every day for 6 months. Many of these dives go  deeper than 800 meters, many reaching over 1,500 meters (4,500 feet). Dives to these depths last around 25 minutes, including the time spent at the bottom and the transit down and back from the surface.

These majestic, seemingly fictitious creatures are, in fact, very real. They are endothermic, mammal, heterotrophs. Narwhals have a very limited, carnivorous diet, that changes throughout the year. In the winter, narwhals feed solely on Greenland halibut or Gonatus squid. Greenland halibut are flatfish found on the bottom of the sea, requiring long dives to be found. During the summer, ice-free season, narwhals eat very little and have nearly empty stomachs.

Narwhals are tertiary consumers, with increasing competition for food. Global Warming is not only reducing the populations of the Greenland halibut and Gonatus squid, but driving whales (including killer whales–one of the few natural predators of narwhals) towards Baffin Bay. This is severely damaging the Narwhal population, which, due to the harsh environment in which the species lives, was already diminishing. Narwhals are generally perceived as predators in relation to smaller consumers; however, they fall prey to killer whales, as well as humans and occasionally polar bears when they rise to the surface for air and rest.

Narwhals live and sleep in the ocean and do not hibernate. They are neither nocturnal nor diurnal. In fact, narwhals do not care whether it is bright or not when they are awake. Due to their sonar, narwhals, as well as many other species of whales and dolphins, rely mainly on their hearing rather than sight. Therefore, narwhals tend to sleep only when tired, and do not have a set “schedule” for their waking hours.

Narwhals are highly dependent on the populations of the Greenland halibut and Gonatus squid thriving, as these species are their only source of food. Together, narwhals and the Greenland halibut and Gonatus squid form a predator-prey relationship that allows the Narwhal to flourish. Another predator-prey relationship that the Narwhal is associated with is with the killer whale. The killer whale is one of the only predators to narwhals, and help to keep the population in balance.

Narwhals reach sexual maturity between the ages of 6-9 years. On average, females give birth to a calf every third year. The breeding period of narwhals occurs in early spring—between March and April—in the confines of the dense ice of their wintering grounds. The gestation period is about 14 months and they give birth to one offspring in late spring—between May and June—during their migration to their summering grounds. The narwhal’s mating rituals are unknown; however, some scientists speculate that the “horn” on male narwhals has the sole purpose of being used in mating rituals, as recent studies have proven “that the bigger the tusks, the better the testes, pretty much—tusk length and teste mass (which indicates fertility) were closely related” (http://time.com/3419809/narwhal-tusks-fertility/).

Narwhals, being mammals, require feeding from their mothers at birth. Narwhals then proceed to live with their parents for approximately 6 months to a year. The average life span of a narwhal is 50 years. During this life span, narwhals are rarely alone because they travel in pods of two to several hundred.