Beluga whales: Social, smart and wizards with sound

Beluga whales are born grey but acquire their characteristic white colour as they mature into adults. Their amazing adaptations to life in the Arctic makes them fascinating, but also vulnerable to threats including climate change and shipping.

Read on to discover some of their unique characteristics.

Where do beluga whales live?

Beluga whales live in Arctic and sub-Arctic waters, including around Russia, Canada, Greenland, and Alaska. Most migrate around these seas. In the summer they like shallow coastal waters, even swimming up estuaries and river deltas to take advantage of spawning fish. In the winter they like to swim around thin or moving sea ice, which they can break through to breathe.

Although belugas live all around the sea ice of the Arctic, they are split into around 21 sub-populations or stocks. 

Despite their cold-loving ways, belugas have been known to stray into UK waters, and in 2018 one was even spotted in the River Thames near London, though it later returned to the sea. Unfortunately, an even more southerly beluga, found in the River Seine in France in 2019, was too stressed by being too long in fresh, warm water, and did not make it back to the ocean.

How they got so off-course is unclear. According to Richard Sabin, Principal Curator of Mammals at the Museum, theories include storms causing navigational errors, or individuals simply following drifting sea ice.

What unique adaptations do beluga whales have?

Belugas are well adapted to life in northern waters. They have a thick skin and a deep layer of blubber to keep them warm and act as an energy store. This can account for 40% of their weight.

Their stark white colouring also helps camouflage them against the ice. Although beluga whales are predators, feeding on fish, crustaceans, and molluscs, they are also hunted by polar bears and orcas (killer whales).

Belugas lack the dorsal fin that stands up from the back of many whales – think of orcas' tall, upright fin. These fins help to keep whales upright while swimming. But for belugas, which swim close under ice, a dorsal fin might have been more of a hindrance. Instead, a dorsal ridge down their spine and a rotund body may help them to move through the water more easily. Lacking a dorsal fin may also help them keep warm, as fins have a large surface areas that can lose heat fast.

When looking at belugas you can't miss their bulbous heads. The large fatty sack between their blowhole and upper jaw is known as a melon. It helps them focus and project sound, making belugas especially good at echolocation - using sound to detect prey and communicate.

Richard says we should appreciate their uniqueness. 'Beluga whales are superbly adapted to live in very hostile environments, thanks to a set of amazing adaptations.'

Are beluga whales sociable?

Beluga whales are very social animals and can show great curiosity towards humans. They usually live in groups of five to 25 individuals but can congregate in mega-pods of up to a thousand animals.

One reason they come together is to have a really good scratch. Many other mammals, including people, shed their skin constantly. Belugas, however, go through a seasonal moult, rubbing off all their old skin in one go. Shallow waters with gritty bottoms are ideal for this activity, which belugas can be seen congregating to do in the summer.

Beluga whales use a wide range of communication sounds, including whistles, squeals, clucks, mews, chirps, trills and bell-like tones. In fact, they are sometimes called 'canaries of the sea'.

These sounds can be transmitted through water and air, and even the hulls of ships. Even more extraordinarily, belugas in captivity have been known to mimic human speech, making sounds several octaves lower than their normal pitch.

Belugas are 'naturally curious and very social animals,' says Richard, noting that they often approach boats and divers. They are also very intelligent, meaning they can be trained. This has been exploited by aquariums and zoos, and even by the US and Russian Navies.

Belugas also have features that make them appear friendlier. Unlike other whales, whose neck vertebrae are fused, belugas can turn their heads from side to side. The melon in their head can also change shape while making sounds, and their face muscles can move, creating 'expressions' that can appear amusingly human.

Are belugas whales or dolphins?

We call them 'beluga whales', but their scientific name, Delphinapterus leucas, means 'white dolphin without a fin'. So which are they?

The distinctions between whales are dolphins are not so clear-cut, with the beluga having characteristics of both.

Dolphins and belugas both fit into the category of 'toothed whales', as opposed to baleen whales that filter food out of water, like blue whales.

Belugas are closely related to the narwhal. This is the only other species in their family, Monodontidae. Narwhals are also an Arctic-adapted species, known for the distinctive long, spiral tusk grown by males.

Whether whales or dolphins, belugas are marine mammals that evolved from creatures that were once land-dwelling, with fore and hind limbs. Now, the fore limbs have become pectoral flippers, while the hind limbs have completely disappeared externally, with only vestigial pelvic bones left unconnected to the spine.

Are beluga whales endangered?

The latest assessment by the IUCN Red List of Threatened Species (in 2017) classified beluga whales as 'least concern', with an adult population of around 136,000 individuals.

However, this obscures the status of the distinct populations living in different regions. For example, an isolated population in Cook Inlet, Alaska, reside in the area year-round. Surveys show that their abundance declined by nearly 50% between 1988 and 1994, and by about 1.3% per year during 1994-2014.

Most belugas are very loyal to their summer residences. This is known as site fidelity, where the animals return to the same deltas and estuaries year after year. This can make them vulnerable to over-harvesting by local hunters. In most areas, hunting is now controlled to keep populations at sustainable levels.

Climate change is a major threat, particularly as it affects sea ice. Changing timings and thicknesses of sea ice influences the belugas' prey and predators, with orcas moving further into their ranges.

The contributors to climate change are also moving into belugas' home waters. As the sea ice abates, new oil and gas drilling projects are being approved and new shipping lanes are opening. Belugas, like other whales, are sensitive to chemical pollution as contaminants accumulate in their tissues.

Industrial intrusions also cause belugas a serious problem in the form of underwater noise pollution. Sound travels much more effectively in water. As belugas rely on their remarkable echolocation abilities, it's no wonder they have been observed avoiding icebreaking ships.

Their narwhal cousins have also been recorded fleeing from loud bursts used for surveying in the oil and gas industry. This behaviour could prevent migration important for feeding and breeding.

What can be done to protect them?

All these threats add up.

'Globally, whales and dolphins face greater threats today than even at the peak of commercial whaling,' explains Richard.

In many regions, the fate of beluga stocks is not well known, as they are not monitored effectively.

Monitoring is important, as the actions of Defenders of Wildlife show. Their work with the Cook Inlet beluga whales not only helped get the stock listed as endangered under the U.S. Endangered Species Act in 2007 and pushed for designation of over 3,000 square miles of critical habitat in 2011, they also funded a tool to house relevant assessment data in one accessible format.

In Alaskan waters, all beluga whales are protected under the Marine Mammal Protection Act. So as well as the Cook Inlet stock, the National Oceanic and Atmospheric Administration (NOAA) monitors the other populations in Alaskan waters - the Beaufort Sea, Bristol Bay, eastern Bering Sea, and eastern Chukchi Sea stocks. Their conservation activities include protecting habitat, responding to stranded belugas, and educating the public.

Richard concludes: 'For beluga whales, more funding is needed to be able to investigate every sub-population. Without knowing more about their behaviours, how they migrate and what threats they face in each area, the right protections cannot be but in place for them.'