Beluga Whales, Delphinapterus leucas
Taxonomy Animalia Chordata Mammalia Cetacea Monodontidae Delphinapterus leucas
Description & Behavior
Beluga whales, aka white whales, Delphinapterus leucas (Pallas, 1776), are incredibly fascinating small whales with a characteristic stocky frame, solid white color, and bulbous melon. The soft and flexible blubber around the head gives the beluga the ability to to change its facial expressions easily. A dorsal ridge, more prominent in males, replaces the dorsal fin found in other whale species. Adult males have flippers that curl upwards. In older individuals, the melon and lips become more pronounced and the skin, though muscular and supple, is quite rough. At birth, calves are gray in color; they lighten to a blue-tinged white around five years of age turning pure white as adults. Males measure between 4-5.5 m in length, with a body weight of between 907-1,361 kg; females are smaller (around 3-4.1 m in length and weighing 454-907 kg). The upper jaw holds nine pairs of teeth, the lower jaw, eight pairs.
Belugas are very gregarious, tending to travel in groups of between 2-15 individuals, with very tight mother/calf associations. These groups are either all cows/calves, or all bulls, the latter of which can extend into larger units of around 500 individuals. Amassed groups of thousands have also been reported, particularly during mating season. This fun-loving species is usually quiet at the surface, but they can become quite noisy and playful in their shallow summer grounds displaying lobtailing and flipper-slapping behaviors.
Before the summer molt, the skin takes on a yellow tinge. When the skin begins to molt, belugas rub themselves along the gravel or sand in seabed. They are often called the "canary of the sea" because of their extended repertoire of vocalizations. They communicate through whistles, "belches" and squeaks. They have an advanced echolocation system and produce broad-band pulses in a narrow beam aimed from their melon.
World Range & Habitat
An exclusively northern hemisphere species, the beluga's range is primarily the Arctic ocean and its adjoining seas (including the Bering Sea and the Sea of Okhotsk) inhabiting fjords, estuaries, and shallow waters. Belugas seek out shallow coastal waters in summer and waters near the ice edge in winter. Except for a small population in the Gulf of St Lawrence, Canada, this species is exclusively an Arctic or subarctic species.
Feeding Behavior (Ecology)
Belugas eat a wide variety of prey, more diverse than most cetaceans. They consume fish species such as herring, cod, and salmon, as well as invertebrates such as octopus, squid, crab, and snails.
Echolocation is thought to aid in the search for food. Feeding dives last from 3-5 minutes, although one individual was observed underwater for 20 minutes diving to a depth of 647 m. Due to the flexibility of the lips—a characteristic only shared by the Irrawaddy dolphin—it is thought that belugas use a "sucking" motion to draw prey into the mouth.
One calf per birth is the rule for belugas. Females give birth every 2-3 years and gestation lasts about one year. Calves weigh about 70 kg at birth. When born, young are a dark brown or black; they become more blue in color between one and two years, then turn a light yellow until they reach sexual maturity when the white color typical of this species is achieved. Young are nursed for about 1.5-2 years.
Longevity: Approximately 35 years.
Estimated Current Population: >150,000 animals.
Conservation Status & Comments
Beluga whale populations have been overhunted to the point where they have been wiped out in some regions. Recovery is hindered by human activities such as river diversion or harbor construction and beluga fertility in some areas is low due to chemical pollution.
Belugas have been hunted for centuries for a variety of products. More recently, it has been harvested by the commercial fishing industry. Beluga meat was sold for human and domestic animal consumption, the blubber was used to make soap, lubricants, and margarine, and the fat of the head was used to make high quality lubricant. Bones were ground up and used as fertilizer, and the skin was tanned to make boots and laces. Presently, the annual kill rate is probably less than 3,000.
The beluga population under the most threat is that of the Gulf of St. Lawrence, Canada, which now numbers between 500-700 individuals. Oil exploration, hydroelectric plants, and shipping accidents are causing considerable disturbance, but they are not the main cause. The whales living in the Gulf are prone to chemical contamination—this industrial area uses the Gulf for the dumping of chemicals (such as DDT) and effluent. For some reason, these pollutants affect belugas more than other species of cetacean (probably due to diet variation), getting into their bloodstream and body tissue, and passing from mother to calf during gestation, often with the calf carrying more pollutant than either of its parents. Deformed calves have been recorded—some bent in an 'U' shape and unable to swim due to a poorly-developed spine. It is disturbing that, due to the high concentrations of contamination, belugas in the Gulf of St. Lawrence population are treated as toxic waste when they die.
NEAR THREATENED (NT) - A taxon is Near Threatened when it has been evaluated against the criteria but does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.
CRITICALLY ENDANGERED (CR) - A taxon is Critically Endangered when the best available evidence indicates that it meets any of the criteria A to E for Critically Endangered (see Section V), and it is therefore considered to be facing an extremely high risk of extinction in the wild.
References & Further Research
Center for Biological Diversity: Cook Inlet beluga whales
Jefferson, T.A., S. Leatherwood, and M.A. Webber, FAO species identification guide, Marine mammals of the world, Rome, FAO. 1993. 320 p. 587 figs.
Smithsonian NMNH - Mammal Species of the World (MSW)
Information about Beluga Whales from NOAA
Kevin Schafer Photography ~ images of wildlife and wild places worldwide
Whale and Dolphin Conservation Society (WDCS)
Research Delphinapterus leucas » Barcode of Life ~ BioOne ~ Biodiversity Heritage Library ~ CITES ~ Cornell Macaulay Library [audio / video] ~ Encyclopedia of Life (EOL) ~ ESA Online Journals ~ FishBase ~ Florida Museum of Natural History Ichthyology Department ~ GBIF ~ Google Scholar ~ ITIS ~ IUCN RedList (Threatened Status) ~ Marine Species Identification Portal ~ NCBI (PubMed, GenBank, etc.) ~ Ocean Biogeographic Information System ~ PLOS ~ SCIRIS ~ SIRIS ~ Tree of Life Web Project ~ UNEP-WCMC Species Database ~ WoRMS
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