Blue Whales are the largest animals that ever lived. They are larger than any dinosaur that ever existed. A large one is equivalent in size to 25 African elephants or the entire National Football League. The skull is large enough to occupy a room. A male's penis is eight feet long. A breaching blue whale can reach the height of a five story building with only half of its body coming out of the water. [Source: Kenneth Brower, National Geographic, March 2009]
Thanks to their speed and the remoteness of their calving and feeding areas, blue whales survived the go go whaling era of the 18th and 19th centuries but the invention of explosive harpoons and steam-powered catcher boats helped make up for lost time. In the first six decades of the 20th century 360,000 blue whale were killed, including entire populations like the ones around South Georgia Island and off Japan. They were hunted mainly for the oil in their blubber and bones and were highly sought after because of their large size and the fact that they were easy to hunt because they stayed near the surface.
One field guide describes the blue whale's color as “a light, bluish gray overall, mottled with gray or grayish white." Kenneth Brower wrote in National Geographic, “but just as often, depending on the light, the back shows as silvery gray or pale tan, Whichever the color, the back always has a glassy shine. When you are up close, you see water sluicing off the vast back, first in rivulets and sheets, and then in a film that flows in lovely, pulsed patterns downhill to the sea." Underwater they are beautiful turquoise blue.
Blue Whale Size:
According to the Guinness Book of Records, the longest blue whale was 110-foot-long female caught near the Falkland Islands in 1909. The heaviest one on record was a 90½-foot-long 190-ton female caught in the Southern Ocean in March 1947. By contrast the largest dinosaurs weighed about 100 tons. One hundred ninety tons is almost half a million pounds.
Brower wrote in National Geographic,"Just as an elephant might pick up a little mouse in its trunk.
So the elephant, in it turn, might be taken up by a blue whale's colossal tongue. Had Jonah been injected intravenously, instead of swallowed, he could have swum in the arterial vessels of this whale, boosted along even ten seconds or so by the slow, godlike pulse."
Blue whales average about 80 feet, about twice the length of a bus. It is not such a surprise that such a large creature is found in the sea. On land its skeletal world have a difficult time carrying that much weight. In the sea, the water takes care of much of weight-bearing duties and bones are not as vital as they are on land.
The brain of the blue whale weighs 15 pounds and is 5 pounds lighter than the brain of the sperm whale. The great whales have the smallest brains of all mammals in relationship to their size. The blue whale's brain represents only 0.005 percent of its total body mass.
Blue Whales Sightings:
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.
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 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."
Blue Whale Characteristics :
Blue whales are members of the roqual family of baleen whales, They can generate 600 horsepower, travel long distances at 20 knots and maintain speed of 12 to 14 miles per hour all day long.
Blue whale flukes are so large they leave behind a whirl of water that is surprisingly long-lasting.
Bruce Mate of the Marine Mammal Institute at Oregon State University told National Geographic, “It's a measure of how much energy is in the stroke." A particularly large flukeprint is a sign that the whale is making a deep dive.
The blue whale's blow hole, Browser wrote, is “a pair of nostrils countersunk atop the tapering mound of the splash guard, built up almost to a kind of nose on the back of the head. Other baleen whales have splash guards too, but not like this. This nose was almost Roman.
It seemed disproportionally large, even for the biggest of whales. Its size explained that loud, concussive exhalation---less a breath than a detonation---and its size explained the 30-foot spout. It was a might blow, followed quickly by a mighty inhalation." When the whale inhales it sucks in enough air to fill a van in a second and a half. The splash guard of the blue whale is big enough for a small child to climb into.
Blues whales are said to have a nasty blowhole smell but not as nasty as that of gray whales. On the smell of a blue whale, Browser wrote, “Now and again the breeze brought a powerful smell of staleness and mold, mixed sometimes with an alarming flatulence...a blast so powerful, so inhumane and malodorous."
The “defecation trail” left by a blue whale Browser wrote is a “brick red streak of processed krill, more watery than particulate." Douglas Chadwick, author several books on whales, said “the loose explosions of dung” he witnessed encompassed “great masses of processed krill that turned acres of sea bright pink."
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.
The gestation period of blue whales is 11 months. It is believed that females choose males based on size. Calves are usually born in April or May. They measure 23 to 26 feet and weigh three tons when they are born. They sometimes reach a length of 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.
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. Weaning takes pace after about a year.
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."
Blue Whale Songs and Communication :
The “pulsing rumble” that blue whales make is said to be the loudest noise made by any animal on Earth. The low-frequency 188-decibel sounds 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 by 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.
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 makes a D call between periods of eating. Blue whale songs are broadcast in a range between 10 hertz and 100 hertz. Typically low frequency sounds 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.
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 a sign of a large, more powerful potential mate. The findings is based on analysis of data collected with hydrophones and other tools.
Blue Whale Feeding:
Blue whales feed almost exclusively on krill, shrimp-like creatures. 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 to navigate their way around the globe to find concentrations of krill. But it is not known how they do this.
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.
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 revealed 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 biomechanical 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 Migrations and Populations:
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.
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 is 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.
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.
In the 1970s, a group of 30 or so killer whales was observed by a SeaWorld Research vessel attacking a 60-foot blue whale. The orcas attacked from different angles. Some attacked from the front; other came up from behind. Several jumped on the blue whale's back, in what may have been an attempt to drown it. Other bit off chunks of blubber, After about five hours the killer whales abandoned the attack, perhaps because they were full or maybe because they were tired.
Endangered Blue Whales:
Blue whales were designated as "protected" by international agreement in 1966 and killing them has been banned since 1967. In the early days of whaling blue whales were able to outpace sailing vessels but did not fare well after steam-powered vessels and 200-pound, cannon-fired explosive harpoons were introduced in the 1860s. In the 20th century they were hunted ruthlessly in waters around Antarctica. That is where the biggest whales were found. More than 29,000 were killed in 1931 alone.
Blue whale populations were devastated by modern factory whaling. By the 1960s they were rarely seen and maybe no more than 10,000 were left. According to one estimate their numbers were reduced by 90 percent between 1945 and 1975. By the 1970s some estimated only a few hundred were left and males and females were so wide scattered it was thought they could not find each other and mate.
Since then blue whales have made a comeback but the come back has been slow and fragile and their numbers are still alarmingly low. About 2,000 to 3,000 range along the eastern Pacific between Oregon and Costa Rica and their numbers are increasing 6 percent to seven percent a year. Around 500 blue whales were counted in California waters in 1979-80; 1,000 in 1991. In the early 2000s, 200 were spotted on a single day around the Channel islands off southern California.
There are thought to be around 25,000 blue whales worldwide, and their numbers could be increasing by 5 percent a year, but details are sketchy. Healthy numbers have been spotted off Australia. Populations around Iceland and Scandinavia are doing better than those off Canada presumably because the waters around Iceland are rich in krill.
The Canadian whales have much higher levels of PCBs than other whales studied. Populations around Antarctica are thought to be not doing so well either but little is known about them. The best guess is that there are about 2,000 Antarctic blue whales. Before human hunting there were maybe 300,000 of them.
Some blue whales have died as a result of collisions with large ships. Whales that feed off of California are vulnerable to strikes from large cargo ships heading in and out of Los Angeles and Long Beach. Relocating shipping lanes and imposing stricter speed limits on ships could help to reduce such accidents.
Studying Blue Whales:
By carefully examining historical records and recording every sighting ever made, scientists have pieced together blue whale's migration routes. Spotter planes are enlisted to locate whales. They circle slowly in areas of clear water where whales are likely to appear. The whales are so big they can often be spotted even when they are fully submerged. Sometimes when one is spotted radio calls are sent out to boats that can reach the area where the whale is spotted in a relatively short period of time. Once there, Zodiacs are launched in the direction of blue whale spouts. Skilled boatsmen can predict where whales are most likely to surface.
A critter cam attached to blue whales 30 or 40 times off the coast of California and Mexico between 1999 and 2004 yielded 100 hours of video. Among the things that were discovered were that the whales dived about 300 meters in an “up and down” patterns. Critter cam teams used small, fast boats to get close to the whales and attached the camera with a fishing pole and a suction cup attached to the camera. The success rate at first was only 10 percent but later it was improved to 50 percent.
Tagging and Taking Tissues from Blue Whales:
Off the east coast of Canada and the west coast of California and Central America scientists in inflatable boats fire special projectiles into the flanks of blue whales to collect samples of tissue, skin and blubber to determine their sex, measure for toxins and take DNA samples. In some places the same whales show up year after year and scientists can identify them based on splotches on their fins and back sides and pigmentation patterns on their sides.
Tissue samples are taken with biopsy bolts attached to an arrow-like projectile shot from a crossbow into the whale. The bolt excises a 7.5-centimeter plug of skin and blubber. The bolt is topped by an oblong ball of yellow rubber that prevents the bolt from going too deep and also allows it to bounce off the whale. The bolts and satellite tags are fired from a pulpit deck on the front of a small boat. The tags are fired from a rifle-like device originally designed to shoot lines between ships. It is powered by compressed air from a scuba tank set at 85 pounds per square inch for a relatively thin-skinned blue whale compared to 120 pounds per square inch for a tough-skinned sperm whale.
Describing the tagging of a blue whale Browser wrote in National Geographic, “The first two whales toyed with us, as usual, calling us close, then pulling away. The third allowed us to get in perfect position. We paced the great turquoise shape, keeping abreast of the fluke as the whale coursed along underwater to starboard. As the animal surfaced to blow, it angled up from turquoise abstraction into photo-realism...Up in the pulpit Mate tucked the rifle stock of the tag applicator into his shoulder, leaned outward at the rising whale. Now just 10 feet underwater. The whale blew, and the glistening wall of its flank erupted in a steep curve above the sea."
“My instructions as biopsy guy were to wait for the bang of the tag applicator before firing my crossbow," Browser wrote. “The smooth flank of the whale filled my whole field of view; there was no way I could miss.At the bang of the applicator, I pulled my trigger. The bolt left the crossbow, and a black hole, small but inky appeared where I had been aiming."
A number of blue whales that have been tagged have been tracked with sun-synchronous, polar-orbiting TIROS N satellites. Echo sounders are used to search for concentrations of krill that blue whales feed on.
Credits : Facts and Details on Blue Whales
Thanks to their speed and the remoteness of their calving and feeding areas, blue whales survived the go go whaling era of the 18th and 19th centuries but the invention of explosive harpoons and steam-powered catcher boats helped make up for lost time. In the first six decades of the 20th century 360,000 blue whale were killed, including entire populations like the ones around South Georgia Island and off Japan. They were hunted mainly for the oil in their blubber and bones and were highly sought after because of their large size and the fact that they were easy to hunt because they stayed near the surface.
One field guide describes the blue whale's color as “a light, bluish gray overall, mottled with gray or grayish white." Kenneth Brower wrote in National Geographic, “but just as often, depending on the light, the back shows as silvery gray or pale tan, Whichever the color, the back always has a glassy shine. When you are up close, you see water sluicing off the vast back, first in rivulets and sheets, and then in a film that flows in lovely, pulsed patterns downhill to the sea." Underwater they are beautiful turquoise blue.
Blue Whale Size:
According to the Guinness Book of Records, the longest blue whale was 110-foot-long female caught near the Falkland Islands in 1909. The heaviest one on record was a 90½-foot-long 190-ton female caught in the Southern Ocean in March 1947. By contrast the largest dinosaurs weighed about 100 tons. One hundred ninety tons is almost half a million pounds.
Brower wrote in National Geographic,"Just as an elephant might pick up a little mouse in its trunk.
So the elephant, in it turn, might be taken up by a blue whale's colossal tongue. Had Jonah been injected intravenously, instead of swallowed, he could have swum in the arterial vessels of this whale, boosted along even ten seconds or so by the slow, godlike pulse."
Blue whales average about 80 feet, about twice the length of a bus. It is not such a surprise that such a large creature is found in the sea. On land its skeletal world have a difficult time carrying that much weight. In the sea, the water takes care of much of weight-bearing duties and bones are not as vital as they are on land.
The brain of the blue whale weighs 15 pounds and is 5 pounds lighter than the brain of the sperm whale. The great whales have the smallest brains of all mammals in relationship to their size. The blue whale's brain represents only 0.005 percent of its total body mass.
Blue Whales Sightings:
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.
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 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."
Blue Whale Characteristics :
Blue whales are members of the roqual family of baleen whales, They can generate 600 horsepower, travel long distances at 20 knots and maintain speed of 12 to 14 miles per hour all day long.
Blue whale flukes are so large they leave behind a whirl of water that is surprisingly long-lasting.
Bruce Mate of the Marine Mammal Institute at Oregon State University told National Geographic, “It's a measure of how much energy is in the stroke." A particularly large flukeprint is a sign that the whale is making a deep dive.
The blue whale's blow hole, Browser wrote, is “a pair of nostrils countersunk atop the tapering mound of the splash guard, built up almost to a kind of nose on the back of the head. Other baleen whales have splash guards too, but not like this. This nose was almost Roman.
It seemed disproportionally large, even for the biggest of whales. Its size explained that loud, concussive exhalation---less a breath than a detonation---and its size explained the 30-foot spout. It was a might blow, followed quickly by a mighty inhalation." When the whale inhales it sucks in enough air to fill a van in a second and a half. The splash guard of the blue whale is big enough for a small child to climb into.
Blues whales are said to have a nasty blowhole smell but not as nasty as that of gray whales. On the smell of a blue whale, Browser wrote, “Now and again the breeze brought a powerful smell of staleness and mold, mixed sometimes with an alarming flatulence...a blast so powerful, so inhumane and malodorous."
The “defecation trail” left by a blue whale Browser wrote is a “brick red streak of processed krill, more watery than particulate." Douglas Chadwick, author several books on whales, said “the loose explosions of dung” he witnessed encompassed “great masses of processed krill that turned acres of sea bright pink."
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.
The gestation period of blue whales is 11 months. It is believed that females choose males based on size. Calves are usually born in April or May. They measure 23 to 26 feet and weigh three tons when they are born. They sometimes reach a length of 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.
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. Weaning takes pace after about a year.
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."
Blue Whale Songs and Communication :
The “pulsing rumble” that blue whales make is said to be the loudest noise made by any animal on Earth. The low-frequency 188-decibel sounds 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 by 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.
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 makes a D call between periods of eating. Blue whale songs are broadcast in a range between 10 hertz and 100 hertz. Typically low frequency sounds 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.
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 a sign of a large, more powerful potential mate. The findings is based on analysis of data collected with hydrophones and other tools.
Blue Whale Feeding:
Blue whales feed almost exclusively on krill, shrimp-like creatures. 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 to navigate their way around the globe to find concentrations of krill. But it is not known how they do this.
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.
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 revealed 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 biomechanical 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 Migrations and Populations:
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.
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 is 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.
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.
In the 1970s, a group of 30 or so killer whales was observed by a SeaWorld Research vessel attacking a 60-foot blue whale. The orcas attacked from different angles. Some attacked from the front; other came up from behind. Several jumped on the blue whale's back, in what may have been an attempt to drown it. Other bit off chunks of blubber, After about five hours the killer whales abandoned the attack, perhaps because they were full or maybe because they were tired.
Endangered Blue Whales:
Blue whales were designated as "protected" by international agreement in 1966 and killing them has been banned since 1967. In the early days of whaling blue whales were able to outpace sailing vessels but did not fare well after steam-powered vessels and 200-pound, cannon-fired explosive harpoons were introduced in the 1860s. In the 20th century they were hunted ruthlessly in waters around Antarctica. That is where the biggest whales were found. More than 29,000 were killed in 1931 alone.
Blue whale populations were devastated by modern factory whaling. By the 1960s they were rarely seen and maybe no more than 10,000 were left. According to one estimate their numbers were reduced by 90 percent between 1945 and 1975. By the 1970s some estimated only a few hundred were left and males and females were so wide scattered it was thought they could not find each other and mate.
Since then blue whales have made a comeback but the come back has been slow and fragile and their numbers are still alarmingly low. About 2,000 to 3,000 range along the eastern Pacific between Oregon and Costa Rica and their numbers are increasing 6 percent to seven percent a year. Around 500 blue whales were counted in California waters in 1979-80; 1,000 in 1991. In the early 2000s, 200 were spotted on a single day around the Channel islands off southern California.
There are thought to be around 25,000 blue whales worldwide, and their numbers could be increasing by 5 percent a year, but details are sketchy. Healthy numbers have been spotted off Australia. Populations around Iceland and Scandinavia are doing better than those off Canada presumably because the waters around Iceland are rich in krill.
The Canadian whales have much higher levels of PCBs than other whales studied. Populations around Antarctica are thought to be not doing so well either but little is known about them. The best guess is that there are about 2,000 Antarctic blue whales. Before human hunting there were maybe 300,000 of them.
Some blue whales have died as a result of collisions with large ships. Whales that feed off of California are vulnerable to strikes from large cargo ships heading in and out of Los Angeles and Long Beach. Relocating shipping lanes and imposing stricter speed limits on ships could help to reduce such accidents.
Studying Blue Whales:
By carefully examining historical records and recording every sighting ever made, scientists have pieced together blue whale's migration routes. Spotter planes are enlisted to locate whales. They circle slowly in areas of clear water where whales are likely to appear. The whales are so big they can often be spotted even when they are fully submerged. Sometimes when one is spotted radio calls are sent out to boats that can reach the area where the whale is spotted in a relatively short period of time. Once there, Zodiacs are launched in the direction of blue whale spouts. Skilled boatsmen can predict where whales are most likely to surface.
A critter cam attached to blue whales 30 or 40 times off the coast of California and Mexico between 1999 and 2004 yielded 100 hours of video. Among the things that were discovered were that the whales dived about 300 meters in an “up and down” patterns. Critter cam teams used small, fast boats to get close to the whales and attached the camera with a fishing pole and a suction cup attached to the camera. The success rate at first was only 10 percent but later it was improved to 50 percent.
Tagging and Taking Tissues from Blue Whales:
Off the east coast of Canada and the west coast of California and Central America scientists in inflatable boats fire special projectiles into the flanks of blue whales to collect samples of tissue, skin and blubber to determine their sex, measure for toxins and take DNA samples. In some places the same whales show up year after year and scientists can identify them based on splotches on their fins and back sides and pigmentation patterns on their sides.
Tissue samples are taken with biopsy bolts attached to an arrow-like projectile shot from a crossbow into the whale. The bolt excises a 7.5-centimeter plug of skin and blubber. The bolt is topped by an oblong ball of yellow rubber that prevents the bolt from going too deep and also allows it to bounce off the whale. The bolts and satellite tags are fired from a pulpit deck on the front of a small boat. The tags are fired from a rifle-like device originally designed to shoot lines between ships. It is powered by compressed air from a scuba tank set at 85 pounds per square inch for a relatively thin-skinned blue whale compared to 120 pounds per square inch for a tough-skinned sperm whale.
Describing the tagging of a blue whale Browser wrote in National Geographic, “The first two whales toyed with us, as usual, calling us close, then pulling away. The third allowed us to get in perfect position. We paced the great turquoise shape, keeping abreast of the fluke as the whale coursed along underwater to starboard. As the animal surfaced to blow, it angled up from turquoise abstraction into photo-realism...Up in the pulpit Mate tucked the rifle stock of the tag applicator into his shoulder, leaned outward at the rising whale. Now just 10 feet underwater. The whale blew, and the glistening wall of its flank erupted in a steep curve above the sea."
“My instructions as biopsy guy were to wait for the bang of the tag applicator before firing my crossbow," Browser wrote. “The smooth flank of the whale filled my whole field of view; there was no way I could miss.At the bang of the applicator, I pulled my trigger. The bolt left the crossbow, and a black hole, small but inky appeared where I had been aiming."
A number of blue whales that have been tagged have been tracked with sun-synchronous, polar-orbiting TIROS N satellites. Echo sounders are used to search for concentrations of krill that blue whales feed on.
Credits : Facts and Details on Blue Whales
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