If you’ve visited the Oceanarium at Shedd Aquarium, you’ve likely heard the calls of Kauyavak, Mauyak, Nala, Kimalu, Beethoven, Bella and Grayson. The seven beluga whales currently on exhibit at Shedd Aquarium all share a unique call that earned their species the nickname “canary of the sea.” The beluga whale uses a large array of vocalizations to communicate with other members of its pod, a social group consisting of about ten individuals. Sound production is of further importance because belugas use echolocation to find prey and to find breathing holes in sea ice. Because they rely so heavily on sound, a major threat to belugas is noise pollution in the ocean due to increased shipping in their northern habitats.
Beluga whales, scientific name Delphinapterus leucas, are a member of the order Artiodactyla, “even-toed ungulates,” despite their noticeable lack of hooves. The phylogenic placement of cetaceans—porpoises, dolphins, and whales—is an interesting one. The evolution of these aquatic mammals is believed to converge from an ancestral quadrupedal land animal, and is thus within the Artiodactyla family, but is nestled in its own infraorder of Cetacea. Belugas share a family, Monodontidae, with only one other extant species: the narwhal, Monodon monoceros. The beluga whale is the only species within the genus Delphinapterus.
Beluga whales live in the cold waters of the Arctic Oceans in the northern waters near Alaska and Canada, Greenland, and Russia, but travel to open ocean during winter months when sea ice thickens. During the summer months, belugas will stay in coastal, shallow waters. Their anatomy is adapted to survival in the arctic habitat. Beluga whales have a stocky, fusiform body shape for easy gliding through the water and distinct white coloration. This white coloring serves as camouflage with sea ice when hiding from predators such as polar bears and orca whales. Belugas have thick layers of blubber, generally concentrated on the ventral side (Naya is easily picked out at the Shedd due to her thick rails of blubber on either side), that aid in insulation. They also lack dorsal fins; this aids is minimizing heat loss; instead, belugas have a dorsal ridge that serves to break up sea ice for breaching. Unlike other cetaceans, the seven neck vertebrae of beluga whales are not fused, allowing for greater mobility of the neck. Beluga whales have a fatty dome on top of their heads called a “melon.” The melon facilitates production of the whale’s various vocalizations. Like all toothed whales, belugas don’t have vocal chords; sound is produced instead in the nasal sacs by the blowhole region. The melon changes shape for different vocalizations. Another adaptation unique to beluga whales is their ability to continuously generate and slough off their skin. Belugas undergo a seasonal molt to shed outer layers of skin after winter months—this can be observed at the Shedd, if a whale seems to be rubbing against the walls, it’s not scratching an itch, it’s sloughing its skin!
Although aptly coined the white whale, belugas are not always white. Female beluga whales give birth to a single calf every two to three years. The calf is born grey and generally develops white coloration around the same time it reaches sexual maturity—around four to seven years of age for males and from four to eight for females. Belugas demonstrate extensive maternal care, beginning with a 14-16 month gestation period. At birth, calves average 5 feet long and about 140 pounds. Calves generally nurse for one to two years, around when they start developing teeth. The Shedd Aquarium’s youngest beluga, Kimalu, was born in August of 2012 to mother Mauyak and father Naluak (currently on breeding exchange at Mystic Aquarium in Connecticut). At four years old, she is still significantly smaller and darker than her Shedd room mates. Fully grown, belugas can range from 10 to 18 feet, and weigh up to 3,400 pounds, with males being about 25 percent larger than females on average. The largest beluga at the Shedd Aquarium, Beethoven, weighs 1,800 pounds. The typical observed lifespan for a beluga whale is about 30-50 years, although a dental study postulates that life expectancy could be as much as 60-70 years.
As adults, belugas are opportunistic feeders. They will feed on fish such as herring, cod and capelin as well as invertebrates such as squid and octopus. In captivity, beluga whales can eat about 30-50 pounds of seafood a day. In the wild, foraging generally ranges from depths of 20 to 40 meters, but can exceed hundreds of meters. A beluga’s ability to hold its breath for up to 20 minutes is beneficial in hunting for food. Although the mouth generally contains 34 teeth, they are dull. As such, the beluga uses suction to swallow its prey whole. Large prey and fish with sharp ventral scales such as shad, pose a risk to belugas—they can get stuck in, or cut the throat when swallowing.
Sharp fish aren’t the only threat to beluga whales, however. As previously mentioned, much of a beluga’s survival relies on hearing and vocalization. As oil and gas industries develop, shipping vessels in the northern habitats increase noise pollution and the risk of injury from such vessels. According to a study conducted in Bristol Bay, Alaska, the hearing capabilities of seven healthy whales ranged from 45 to 150 kilohertz. This range is consistent with the hypothesized acute sensitivity of beluga whale hearing. This information is vital in demonstrating the importance of beluga whale hearing with respect to mating, young-rearing, and hunting. Anthropogenic noise interference can be detrimental to the survival of these animals.
As a species relying heavily on frigid temperatures and sea ice, climate change is a significant threat to belugas, and partly responsible for their “Near Threatened” designation on the IUCN’s Red List. According to one study conducted in 1997, climate change could potentially result in a geographic range shift and a decline in reproductive success for these whales.
Belugas are hunted for human consumption as well. Because their migratory patterns are predictable, some populations have consequently experienced a significant decline. Hunting subsistence legislation such as catch limits established by the Joint Committee on Narwhal and Beluga/North Atlantic Marine Mammal Commission has helped some ranges replenish.
The Shedd Aquarium has partnered with many local Chicago restaurants in hopes to tackle another threat, not only to belugas, but to all ocean ecosystems. Overfishing for human seafood consumption has led to resource depletion for much of the aquatic wildlife that relies on the same seafood for survival. The Shedd Aquarium has developed a Sustainable Seafood Action Guide to help consumers in picking sustainable and local seafood options, be it at the market or at a restaurant. Local Chicago restaurants such as Uncommon Ground and Fish Bar work with Shedd Aquarium to serve only sustainable seafood options. Monterey Bay Aquarium has also partnered in the sustainable seafood crusade: the free Seafood Watch app (and website) provides up-to-date information for responsible seafood options. With the help of consumers like you, fish can be friends and food.
Featured photo courtesy of Hakkeijima Sea Paradise on Yokohama Island, Japan