BLUE WHALE BEHAVIOR
Blue whale are solitary and migratory (make seasonal movements between regions, such as between breeding and wintering grounds) and solitary. They live in all the world's oceans except the Arctic. They sometimes swim in small groups but usually alone or in pairs. They generally spend summers feeding in polar waters and undertake lengthy migrations towards the Equator as winter arrives. [Source: Tanya Dewey and David L. Fox, Animal Diversity Web (ADW), NOAA]
Blue whales sense using touch, sound and chemicals detected by smelling. They communicate with sound. Little is known about their communication in these whales. Vision and smell are limited, but hearing is sensitive. Blue whales are among the loudest animals on the planet, emitting a series of pulses, groans, and moans, and it is thought that in good conditions, blue whales can hear each other up to 1,600 kilometers (1,000 miles) away. Scientists think they use these vocalizations not only to communicate and — along with their excellent hearing — to sonar-navigate the dark ocean depths.
Most populations of blue whales are migratory though some animals do not migrate. Migrators typically spend the winter in low latitude waters, move towards the poles during the spring, feed in high latitude waters during the summer and head back toward the equator during the fall. There are northern and southern ocean populations that remain distinct. Feeding is usually at depths less than 100 meters (330 feet); harpooned animals have dived as deep as 500 meters. Normal dives last from 10-20 minutes and are separated by 8-15 blows. The spout of blue whales can reach almost 10 meters. Aggregations of up to 60 animals have been reported, but solitary animals or pods of two or three are more common. /=\
Swimming Blue Whale
blue whale baleen plates
Describing what it is like to encounter a blue whale the naturalist David Attenborough wrote, “the sapphire blue of the Pacific water begins to pale. You realize that something flat, horizontal and vast is slowly rising from the depths towards the surface. It’s the whale’s tail. You look ahead, seventy feet, almost the length of a tennis court, and a grey hump break the surface with waves swilling over it. It is so far away that it hardly seems possible for it to be connected to the flat, white shape still residing beside our dinghy. A pair of nostrils opens in the distant hump and with a whoosh, a blue of vapor blast thirty feet in the sky.”
“The whale is idling,” David Attenborough wrote. “Even so it is sliding through the water so swiftly the dinghy can barely keep up with it, The whale’s head may rise and spout a few more times but then the tail breaks the surface and rears up into the air, dripping water. It is as wide as the wing of a small aircraft. The next dive the whale will make will be a deep one. It may be gone for an hour and you can have little idea of where it will have traveled to in that time. Your encounter is over.”
On the impact of a blue whale on the surface of the sea, Brower wrote, “There is the oil slick that forms above the head the moment before emergence, the long, narrow slick left by the arching back. There are the sputtering white fountains that a blue whale raises by blowing early, still gliding under the surface — a sequence of premature spouts. There are bubble blasts. I saw my first of these just ahead of the bowsprit, about 12 feet deep, as the blowhole of the whale erupted a big bolus of bubbles. It expanded toward the surface, vitreous and glittery, like a crystal chandelier falling upward.”
High Speed “Racing” Blue Whales
Blue whales typically cruise the ocean at more than 8 kilometers per hour (5 miles an hour) but Normal swimming speed can be as high as 22 kilometers (15 miles) per hour. They can accelerate to more than 32 kilometers (20 miles) an hour for short bursts and may reach speeds of 48 kilometers (30 miles) per hour when alarmed.
Blue whales are rarely observed traveling at high speeds but in August 2022 off Dana Point, California, boaters saw at least three blue whales, racing behavior in a what was described by one naturalist as “one for the record books.” FTW Outdoors reported: In a video captured by Capt. Dave’s Dana Point Dolphin & Whale Watching three blue whales are shown interacting in what might be courtship behavior: “Possibly two males competing for the attention of the female,” Capt. Dave’s wrote. “There appears to have been physical contact and, at times, the whales were clocked at 15 knots, or just above 17 miles per hour”. [Source: Pete Thomas, FTW Outdoors, August 24, 2022]
It’s remarkable, considering that blue whale sightings typically involve slow and predictable movements as the mammals, which can measure 100 feet, surface to breath and sometimes reveal tail flukes as they begin to dive. Dana Wharf Whale Watch posted 21 images captured by Laura Lopez to Facebook. She wrote: “On our first two trips, we saw groups of four blue whales often swimming very close together — side by side, rolling [and] displaying ventral pleats, pectoral fins and tails, simultaneous high chin slaps while racing across the water at high speeds. Other times, they seemed to be following in a line up all bursting the water’s surface together. One or two whales would separate from the group and then rejoin. These behaviors indicate the whales could likely be engaged in courtship.”
Blue Whales — the World's Loudest Animals?
Blue whales can create the loudest sounds of any living thing. Their calls can reach over 180, maybe as high as 200, decibels — as loud as a jet plane, a world record. They also have the lowest voices of any whale, vocalizing as low as 14 Hz at volumes. Sounds at this frequency and intensity can travel for thousands of kilometers in the deep ocean and may be used to communicate with other whales. Low frequency pulses may be used to navigate by creating a sonic image of distant oceanic features. [Source: Tanya Dewey and David L. Fox, Animal Diversity Web (ADW) /=]
The low-frequency, 188-decibel “pulsing rumble” sounds of blue whales can be picked by can be picked up by communication equipment 900 kilometers miles away and might be heard by other blue whales half an ocean away. Most of the sounds they produce are too low for humans to hear but can easily be picked up underwater microphones used to track submarines. Whales in different areas have different calls. Little is known about the purpose of the calls. It not even known who produces them, males or females or both. It is widely believed though that most of the songs are made by males seeking mates.
Sperm whales are the loudest animals, but many believe blue whales are louder because of call duration. USA Today reports: The sperm whale is technically the loudest animal in the world, but the answer is up for debate because how we perceive loudness is subjective. [Source: Clare Mulroy, USA TODAY]
According to BBC, the sperm whale is perceived to be louder than the blue whale. A blue whale's call is 20 Hz and a sperm whale’s click is about 10,000 Hz. The sperm whale registers at 230 dB while the blue whale is at 188 dB. “For us to hear blue whale calls, they must be made at an intensity of 70 dB or more,” BBC writer Ella Davies reports. “But for sperm whale clicks, the human hearing threshold is around 15 dB.”
But the other factor is duration — a sperm whale’s click only lasts 100 microseconds while a blue whale call can last up to 30 seconds, BBC reports. Sound is also perceived differently underwater because water is denser than air. It travels faster and further in the water. So the sperm whale is technically louder, but if you perceive sound based on combined loudness and duration, the blue whale is a close contender. For comparison: the loudest human yell was 129 decibels. The loudest dog bark was 113 decibels. At 70 decibels, you may feel annoyed by the sound. At 140, you'll feel pain.
Blue Whale Songs
Blue whales “songs” consist of, reverberating moans with single notes lasting for a half a minute or more. The sounds are produced by massive bursts from the larynx and lungs and burst and is comparable in loudness to the roar produced by the launch of space-shuttle-carrying rocket. Browser described the song of the blue whale bull as a “thumping, stentorian, basso profundo pulse of the A call, followed by the continuous tone of the B call.” In addition to this it make a D call between periods of eating. Blue whale songs are broadcast in a range between 10 hertz and 100 hertz. Typically low frequency sound travel further but to according to acoustic physicists “there is no practical difference in the sound transmission properties in the deep ocean and it’s easier to make a powerful sound at high frequencies. [Source: Kenneth Brower, National Geographic, March 2009]
Scientists at Scripps Institution of Oceanography have noticed that blue whale songs have dropped in frequency by as much as 30 percent over the past 40 years, possibly because of rebounding populations. The scientists theorize that males might not need to sing so loudly to reach females, and a deeper song may be more advantageous, perhaps because it is sign of a large, more powerful potential mate. The findings is based on analysis of data collected with hydrophones and other tools.
Not much is known about blue whale songs, although most researchers think that they help males woo their mates, as is the case with closely related species. Groups of blue whale that have different songs are often either subspecies or subspecies like. Asha de Vos, a marine biologist who has studied blue whales in the Indian Ocean, told the New York Times. Any modifications to a blue whale song is fairly high stakes, de Vos said: “If two populations can’t talk to each other, over time, they’re going to grow apart.” “Eventually, populations with different takes on a tune might splinter into subspecies, with their own behaviors and quirks. There’s not yet evidence to show that has happened with these blue whales, nor much information on what might have driven them apart from their southerly kin. But even if the whales in this new group don’t yet formally occupy a new branch on the tree of life, they are worth getting to know. “What things like this show us is that there are different populations, with different adaptations, with potentially different needs,” de Vos said. To conserve the world’s blue whales, she said, “there’s not one single protection measure that’s going to work.” [Source: Katherine J. Wu, New York Times, December 25, 2020]
Dr. Emmanuelle Leroy of the University of New South Wales (UNSW), Sydney said the songs of blue whales usually can travel anywhere between 200 to 500 kilometers (125 to 310 miles) underwater, yet they remain mostly inaudible to the human ear. Unlike humpback whales, for example, which are “like jazz singers” that change their songs all the time, blue whales like more structure, Rogers said. “Even so, different blue whale populations are known to diversify their melodies from time to time, “similar to generational slang between humans,” according to the UNSW release. [Source: Katie Camero, Lexington Herald-Leader, June 12, 2021]
“What’s more, these songs can teach scientists about the animals’ population, spatial distribution and migration patterns.. “We still don’t know whether they’re born with their songs or whether they’ve learnt it,” Rogers said. “But it’s fascinating that within the Indian Ocean you have animals intersecting with one another all the time but whales from different regions still retain their distinctive songs. “Their songs are like a fingerprint that allows us to track them as they move over thousands of kilometers.”
Blue Whale Feeding
The primary and preferred prey of blue whales is krill — tiny shrimp-like animals. They whales strain huge volumes of ocean water through their baleen plates (which are like the teeth of a comb). Adult whales can ingest three to 4 tons of krill per day. Some of the biggest individuals may eat up to 6 tons of krill in 1 day. During the height of the feeding season an adult can devour as much as eight tons of krill a day. It is assumed that their primary mission in life is navigate their way around the globe to find to concentrations of krill. But it is not known how they do this. [Source: NOAA, National Geographic]
Blue whales feed almost exclusively on krill but fish and copepods (tiny crustaceans) may occasionally be part of the blue whale’s diet. In southern waters blue whales mainly eat Antarctic krill (Euphausia superba), which are than seven centimeters in size and hugely abundant. In northern waters they mainly eat the krill species Thysanoessa inermis and northern krill (Meganyctiphanes norvegica) though other planktonic species and small fish are also eaten. [Source: Tanya Dewey and David L. Fox, Animal Diversity Web (ADW) /=]
Blue whales, fin whales, and minke whales are known as gulpers. They filter great mouthfuls of the sea and everything in it. When feeding they distend their pleated throat so the mouth fills with water and then expel their water by pushing forward their large fleshy tongue. When filled with water the pleated pouch can expand to four times its normal size. When hunting for food, blue whales filter feed by swimming toward large schools of krill with their mouth open, then push the water out of their mouth with their tongue while keeping the krill trapped inside their baleen bristles.
Blue Whale Feeding Patterns
As a study published in 2021 off the U.S. West Coast showed, blue whales eat about 10-20 tons of krill daily, while fin whales eat 6-12 tons of krill and humpback whales eat 5-10 tons of krill or 2-3 tons of fish. The new study found that the whales primarily feed at depths of 165-820 feet (50–250 meters). [Source: Will Dunham, Reuters, November 2, 2022]
Off Australia, blue whales have been observed by plane feeding on surface with their bodies turned sideways and the huge mouths agape, sweeping through the water. Sometimes they dive several hundred feed below large concentrations of krill and rush upwards with their mouth open wide.
Acoustic tagging has reveled the feeding pattern of blue whales feeding at the Costa Rica Dome. There they sink headfirst to a depth of about 225 meters, then lunge upward about 50 meters through a mass of krill with its mouth agape and pleated pouch bulging. Then it pauses while its tongue pushes water out of the mouth, leaving krill behind. The process is repeated as the whale dives and surfaces about four or five times an hour.
Blue whales lunge when they feed in what Donald Croll of the University of California at Santa Cruz calls “the largest biomechincal event on Earth.” The massives whales can take in tens of thousands of gallons of water and millions of krill — almost 70 percent of their body weight — at one time. The tongue is as large as an elephant. It forces water through the bristle-like baleens that hang from the whale’s upper jaw. The krill are then swept of the baleen with the tongue and swallowed.
Blue Whale Reproduction
Blue whales are viviparous, meaning they give birth to live young that developed in the body of the mother. A lot remains unknown regarding breeding areas and patterns, but blue whales typically give birth in tropical or subtropical waters. A newborn blue whale calf weighs approximately two tons, (1,800 kilograms, 4,000 pounds) .
Blue whales engage in seasonal breeding. Females give birth to young every two to three years. The breeding season is from during the winter months, with the average number of offspring being one. Twins are rare but do occur occasionally. The best available science suggests the gestation period is approximately 10 to 12 months, and that blue whale calves are nursed for about six to seven months. The age in which they become independent ranges from two to three years. Blue whale young are cared for extensively by their mother. Male blue whales do not contribute parental care. [Source: Tanya Dewey and David L. Fox, Animal Diversity Web (ADW) /=]
Scientists know little about the life history of the blue whale. Most reproductive activity, including births and mating, takes place during the winter. It is believed that females choose males based on size. The gestation period of blue whales is remarkably short for an animal its size. Sexual maturity occurs after five years old when females are about 21 to 23 meters in length. Males mature at 20 to 21 meters. /=\
No one has ever seen blue whales mate or give birth. The Costa Rica Dome appears to be a calving and mating area as mothers and newborn calves have been observed there as have several blue whale threesomes, with boisterous scouting activity, suggesting mating activity. The presence of whales tagged in California shows a clear link to that whale population but a large number of whales not seen elsewhere suggest that blue whales also come from other places, perhaps even Antarctica.
Blue Whale Young
Baleen whales such as grays, humpbacks and right whales that have been studied in the calving grounds rarely feed when they are mating or giving birth. This does not seem to be the case with blue whales which appear to feed extensively when they are in their calving areas, perhaps because they are just so large and need so much food.
Blue whales calves are usually born in April or May. They measure seven to eight meters (23 to 26 feet) and weigh two to three tons when they are born. They sometimes reach a length of 18 meters (60 feet) after their first year. It is said that blue whale young double their birth weight in the first seven days. It takes a human baby about 120 days to achieve this.
Blue whale calves are relatively well-developed when born. Pre-fertilization protection and pre-birth, pre-weaning and pre-independence provisioning and protecting are done by females. Young are born in warm, low latitude waters in the winter months after the adults return from their high latitude feeding grounds. Weaning probably occurs on, or en route to, summer feeding areas. While nursing, blue whales can gain up to 90 kilograms in body weight a day. Young are weaned usually after attaining a length of 16 meters. [Source: Tanya Dewey and David L. Fox, Animal Diversity Web (ADW) /=]
Young blue whales feed solely on their mother’s milk, which is 40 percent fat. A calf gains weight at a rate of about four kilograms an hour. During her seven-month lactation period a female blue whale can lose up to 25 percent of its body weight. Describing a calf and mother Browser wrote in National Geographic, “the pair were moving slowly, spending a lot of time to the surface. The mother surprised us by by allowing her calf to turn towards [the boat]...A mother whale often interposes herself between her calf and potential danger, but this mother was an easygoing Montessori sort of parent, and she left her baby explore.” [Source: Kenneth Brower, National Geographic, March 2009]
Blue Whale Migrations
These days blue whales are often seen off the southern coast of Australia, the west coast of the United States and Baja California and in the Gulf of St. Lawrence in eastern Canada. The eastern Pacific population, thought to be the world’s largest, feeds through the summer off of California and migrates south to Central America, where it winters, calves and feeds in the Costa Rica Dome, an area of upwelling of cold nutrient-rich water, between 300 and 500 miles offshore. Not all the California whales head there. The tagging of whales indicated that some meander around waters near Oregon, Washington and British Columbia and winter off of Mexico. There is also evidence that blue whales come from as far away as the Antarctic to feed at the Costa Rica Dome. [Source: Kenneth Brower, National Geographic, March 2009]
Despite their size blue whales are very elusive because they are largely solitary and move in unpredictable ways through the open sea in all of the world’s oceans. They rarely come near shore. Their powerful flukes can power them for many days without a single stop. Of three whales tagged near San Francisco, three weeks later one showed up in southern Baja California, another was found off Oregon and another was 1,200 miles out at sea. [Source: Kenneth Brower, National Geographic, March 2009]
About ten different blue whales summer-and-winter migrations patterns have been roughly sketched out, each associated with a distinct population: 1) between southern Alaska and northern Hawaii; 2) along the west coast of North America; 3) along the west coast of South America; 4) along the east coast of Canada; 5) between the southeast coast of South America and Antarctica; 6) between the southeast coast of South Africa and Antarctica; 7) between the west coasts of Scandinavia and Africa; 8) between the southern Indian Ocean and Antarctica; 9) between the southern Australia Ocean and Antarctica; and 10) off Russia’s Kamchatka Peninsula
It not known how closely these populations are linked if they are linked at all. Some may be subspecies or even separate species, So-called pygmy blue whales found in the Indian Ocean are about 10 feet shorter than others.
Image Source: Wikimedia Commons, NOAA, International Whaling Commission
Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.
Last Updated May 2023