Beluga whales (Delphinapterus leucas) are known for the stark white color and interest in human activity. These easily-identifiable whales fall into the infraorder, Cetacea. This grouping also includes dolphins, killer whales, and blue whales. Today, let’s better understand: what is a beluga whale?
Beluga whales are one of the most common whales found in captivity. This is largely due to their easily identifiable and distinct morphology. Several characteristics separate belugas from other whales.
- Length: Beluga whales are one of the smallest species of whales. The males, which are bigger, generally range from 3-6 meters (10-20 feet). The females are about 25% smaller, ranging from 3-4 meters (10-13 feet).
- Mass: While belugas may be one of the smallest whales, that doesn’t mean that they’re light! Males clock in at 1,000 to 1,600 kg (2,200 to 3,530 lb) and females from 700 to 1,200 kg (1,500 and 2,650 lb). This is as much as a Honda Accord!
- Color: The color of beluga whales is arguably their most distinctive feature. At birth, most D. leucas are greyish-white or greyish-blue. As they age, the pigment in their skin fades until they are entirely white. This white coloration is an adaptation to living amongst icebergs and snow. This helps to hide beluga whales from predators like polar bears and killer whales.
[Image by Greg Hume (Greg5030) / CC BY-SA]
Beluga whales are well-suited for the cold waters of the Arctic, Atlantic, and Pacific Oceans. They live off the northern coasts of Canada, Greenland, and Russia.
- Location: Belugas generally live in cold arctic and sub-arctic waters. During the summer months, they remain between 76°N and 80°N. The furthest south that the whales inhabit is thought to be the St. Lawrence River in Canada. Surface temperatures in this part of their habitat typically reach 75°F. This is warm compared to the daily highs of about 32°F in the North Pole.
- Depth: Belugas preferentially choose different depths of water depending on the season. In the warm summer months, the whales will rest in coastal waters that are often barely deep enough to cover their bodies. In the winter months, they will transition to areas with deeper water, around 800 meters (2,500 feet).
- Migration: Most beluga whales migrate, and some will migrate over 6,000 km (3,700 miles). During the fall, the coastal regions in which they prefer to live become blocked with ice. As a result, the whales will migrate into deeper waters along the edges of sea ice.
Like many other whales, extensive research exists concerning their behaviors and trends.
- Social structure: Beluga whales are extremely social animals. They typically live in groups called pods that vary in size from two or three to 25. Three types of pods generally make up their social structures. Nurseries include females and calves (young whales). Bachelor groups are made up of males. Mixed groups can contain males, females, and young. Belugas do not typically stay with a single pod for long periods of time. From radio-tracking data, scientists know that the whales will sometimes spend time in several pods over the span of a week.
- Diet: Beluga whales are like the dogs of the sea. They will eat almost anything that they can catch. Because of this, their diet depends largely on where they are located. Off the coast of Alaska, researchers sampled belugas from different “stocks” and discovered a wide variety of stomach contents. Stocks are groups that tend to stay together in the same coastal areas. For the Beaufort Sea stock, the predominant fish in their system was Arctic Cod (21% of whales had this fish in their system). In the Cook Inlet, belugas tend to prefer Pacific Salmon (81%). “Isopods, bivalves, amphipods, and echiurids” were also commonly found.
- Reproduction and Lifespan: Like most whales, belugas have very long lifespans relative to many terrestrial animals. While there is some disagreement about the max lifespan, researchers generally estimate their lifespan to be 30-35 years. Most belugas will reach sexual maturity around 7-10 years of age. Female whales will give birth to a calf roughly once every three years.
The worldwide population of beluga whales is roughly 150,000. The whales are considered to be of status “least concern” by the International Union for Conservation of Nature’s Red List. While this is encouraging, several problems threaten the continued healthy status of beluga whales.
- Hunting: Beluga whales have been hunted for sustenance for thousands of years. They are excellent prey due to their large pod size and predictable migration patterns. Recently, there has been a downturn in the number of whales killed per year, but the number still is likely over 1,000.
- Pollution: Oil, gas, and wastewater discharge are just a few of the most common contaminants that tend to collect in the oceans. While these may exist in relatively low concentrations, they tend to become more concentrated in animals higher up the food chain (such as belugas) in a process known as biomagnification. As a result, the whales can accumulate dangerous amounts of toxins in their blubber, which can threaten their reproductive and immune systems.
- Food limitations: In part due to global climate change, there are fewer fish in the ocean for consumption – both for our own consumption and that of whales. This means that, in the future, belugas may face more severe challenges in locating enough nourishment.
Featured image by nikkikeldsen via Pixabay