The Canary of the Sea: The Beluga Whale
The Beluga whale (Delphinapterus leucas) is a Cetacean and the only other member of the family Monodontidae, along with the Narwhal. They are also commonly known as the white whale due to their identifiable colouring, this however only establishes when the whales reach sexual maturity at approximately 5 years. Until that time calves remain a grey/brown colour. They are called the ‘Canaries of the Sea’ because of their extensive development of language with the widest range of vocalisations of any whale species; this is just one of many factors that make the Beluga whale unique and interesting.
Why are Beluga whales important?
They are extremely sociable and live in large pods ranging from just a few individuals to several hundred, within these pods Beluga whales will hunt, migrate, and communicate with each other. Beluga’s play an important role in the arctic ecosystem as they are top of the food chain, therefore are carnivores but also opportunistic feeders so their diet is comprised of everything from fish species to worms. These whales, are also culturally important to the native communities in the Arctic, and still to this day are hunted by the indigenous people to harvest their meat for sustenance. This threat however is somewhat insignificant in comparison to the much greater threat of climate change. Much like many other Arctic species such as the polar bear, Beluga whales have adapted to and rely solely on sea ice as a habitat, however data now suggests there will be no sea ice in the arctic during summer months by 2040. Therefore, its questionable how long will the Beluga whale be able to survive and what will happen to the arctic ecosystem if it doesn’t?.
Beluga whales are circumpolar and are distributed in Arctic regions, but have been known to migrate into sub-arctic areas, moving south in the winter months when sea ice forms. Nonetheless their distribution is localised to these specific regions around Canada, Russia and Greenland. Within these areas, they are generally found in shallow coastal waters, and surprisingly in river mouths. In some cases, Beluga’s were even found travelling up the river, suggesting that they are well adapted to both deep cold saline water and shallow warmer freshwater.
Beluga’s are relatively small whales with an average length of 4-5 metres and a lifespan between 35-50 years. They have a distinctive large bulbous ‘melon’ on their head which is flexible and can change shape, this is used to both focus and produce sound for echolocation. Interestingly Beluga whales also have flexible lips and are able to create a variety of facial expressions. These whales are also a unique cetacean as they molt annually in the summer around July whereby they gather in shallow waters and use the rough substrate to remove the top layer of skin. Not only do these physiological factors make them unique compared to many other cetaceans, they have specialised adaptations which allow them to survive and live endemically in arctic conditions.
Adaptations to the Arctic environment.
Firstly they are lacking a dorsal fin but instead have a toughened dorsal ridge along their back this reduces external surface areas where body heat can be lost in the cold arctic water. More interestingly unlike other cetaceans, Beluga whales have unfused cervical vertebrae which allows them more flexible movement of their head, an adaptation thought to enhance their ability to catch prey in mud and ice covered areas. Furthermore, they have a thicker layer of blubber, up to 15cm thick, which makes up approximately 40% of their total body mass to provide more insulation and energy stores minimising the loss of body heat in the arctic environment.