© Pascal Kobeh / naturepl.com / WWF
Narwhal
Behaviours
Discover more about narwhals behaviours – how they communicate with each other, feed and mate in the Arctic Ocean.
© Doc White / naturepl.com / WWF
Communication: How do narwhal communicate?
Narwhals communicate through echolocation using clicks, whistles and pulsed calls at different frequencies and rates.
To communicate through echolocation, scientists have found that narwhals communicate in maximum amplitudes at 48kHz with rates of three to 10 clicks per second. Faster click rates have also been recorded at 110 to 115 clicks per second and maximum amplitudes of 19 kHz. In narwhal wintering grounds, scientists have recorded high frequency clicks that have reached up to 200kHz.
Whistles or other calls are thought to be social signals among narwhals, and range between 300Hz to 18kHz.
Listen to a narwhal making calls in the wild.
Audio via © Ari Daniel Shapiro and the Woods Hole Oceanographic Institution
Diet: What do narwhal eat?
Narwhal have a limited number of prey in their diet.
During summer, scientists have found that narwhal feed sparingly. However, narwhal feed heavily in late autumn and winter, mainly on Gonatus squid and Greenland halibut.
There are regional differences in diet between narwhal populations. The Northern Hudson Bay population of narwhal tends to feed on bottom-dwelling prey. The narwhal population in East Greenland focus on prey in the water column. Baffin Bay narwhal focus on prey that is higher up in the food chain, such as Greenland halibut.
Having a limited diet could cause problems for narwhal in the future. Scientists think that narwhals’ limited selection of prey might affect how as a species they adapt to a changing food web as a result of climate change.
© Eric Baccega / naturepl.com / WWF
Mating and reproduction: Narwhal life history
In both Greenland and Canada populations, narwhal mating season occurs in May and June. Calves are then born the following year sometime in June, July or August, meaning female narwhal carry their calves for 11 to 15 months before giving birth. Female narwhals are thought to give birth to one calf every three years, but scientists need more data to make conclusive statements about this life history strategy.
After a female narwhal gives birth, their calves remain with them and are nursed for one to two years. Newborn narwhal calves are approximately 160 cenitmeters long and are born grey or a dark-brownish grey. However, during the nursing period, calves change colour and develop white patches, which gives narwhal its molted appearance.
When a male narwhal reaches approximately 250 centimeters in body length, its tusk starts to develop. Narwhal reach sexual maturity at around eight or nine years old and approximately 350 centimeters in body length for females and more than 350 centimeters for males.
A fully grown female narwhal is around 400 centimeters in body length and weighs 900 kilograms. A male narwhal is around 450 centimeters in body length and 1600 kilograms in weight.
As narwhal age, they can lose their molted pattern. Old adult males can become almost completely white except for a thin dark-spotted pattern on their back.
Narwhal also have a low dorsal ridge instead of a dorsal fin, just like beluga and bowhead whales, which helps with being able to dive under the sea ice.
