Those Amazing Singing Whales!
Who else can make fishing nets out of bubbles, turn 40-ton backflips, and hold concerts under water?
“KEEP your eyes on that light-green slick to the right of the boat!” There was a rush to that side of the boat, and I was just in time to see the huge gaping mouth shoot up through the center of the slick. As it took in a couple of barrelfuls of water, the pleated throat ballooned out under the weight of its load. The upper jaw, its curtain of fringed baleen plates hanging down like an oversized broom, closed over the pool just engulfed.
I had just seen a humpback whale grab a bite to eat.
Two hours earlier, some 30 passengers and crew had sailed from Gloucester, Massachusetts, on the Daunty II for a day of whale watching. Mason Weinrich, director of the Cetacean Research Unit located there, and author of Observations: The Humpback Whales of Stellwagen Bank, had made some general comments about the humpbacks. We had seen some of their spouts in the distance, and a few closer to us had arched up for a breath of air. And those knobs so noticeable on the humpback’s head? Hair follicles, we were told. Each one contains one or two short hairs, believed to act as sensors, like a cat’s whiskers.
Then came Weinrich’s sudden cry that halted all inquiries and sent us scrambling to the right side of the boat and to our first close-range view of a humpback feeding. It was only the beginning of the excitement. After all, it takes several bites to fill a stomach that holds 1,300 pounds (590 kg)!
“Where we are, here on the Stellwagen Bank,” Weinrich said, “the humpbacks feed primarily on sand lance, a small fast-swimming baitfish. In order to capture them in sufficient numbers, the humpback uses a strategy known as bubble clouding. The whale releases a blast of bubbles underwater that surfaces as a large, light-green slick. Just what this does is not known. Maybe it confuses or concentrates the sand lance or disguises the whale. Whatever it does, it works. Some 10 or 20 seconds after the bubble cloud appears on the surface, the whale comes up in the center of the slick with mouth agape, as you’ve just seen.”
Weinrich then explained what happened next: “You saw the series of pleats on the throat expand as the water poured into his lower jaw. These pleats extend down to the middle of the belly and are separated from the body by a wall of muscle and connective tissue. When they balloon out with the inrushing flood, they form a very large storage basin for both water and prey. Next, as the mouth partially closes, the muscles in the pleats contract like an accordion. At the same time the tongue exerts pressure, and the water is pushed out of the whale’s mouth. But the small fish stay behind, strained out by the baleen plates. Incidentally,” Weinrich added, “those baleen plates were once used to make corset stays.”
Fishing Nets Made With Bubbles
“The bubble clouds used by the humpbacks on Stellwagen Bank,” he told us, “would not work in Alaskan waters where the krill are not densely concentrated. There the humpbacks use a bubble net to concentrate and trap their prey.”
Later I saw in National Geographic a picture of this bubble net and a description of how it works: The “ingenious hunter solves the problem of herding scattered morsels into a bite-size feast by blowing a bubble ‘net.’ Like a giant undersea spider spinning its web, the humpback begins perhaps fifty feet deep, forcing bursts of air through its blowhole while swimming in an upward spiral. Big bubbles, followed by a mist of tiny ones, rise to create a cylindrical screen that concentrates krill and small fish. Bubbles and food pop to the surface, followed by the gaping mouth of the whale as it emerges in the center of its net.”
But right now on our whale watch I was seeing and learning more about the humpbacks on Stellwagen Bank. I was especially impressed with one thing. That day we saw some 20 different humpbacks, and Weinrich could call out the name of every one if he saw the underside of their flukes. No two humpbacks have the same fluke markings. For identification, they are as reliable as fingerprints! A very useful thing for researchers in this field. Once photographed, that same whale could be identified by this photograph wherever it might go, into whatever ocean it might roam.
During the past several years, thousands of humpback flukes have been photographed, filed, cataloged, and computerized at the College of the Atlantic in Bar Harbor, Maine. By 1984, over 3,000 had been recorded. New photographs of whales sighted can be compared with this master file and either be identified by it or be added to it.
The humpbacks that day showed us many interesting maneuvers. They would be underwater with only their tails showing and then repeatedly slap the water with their flukes—lobtailing. They would rest with their heads poked up out of the water and gaze all around—spy-hopping. From the surface they would dive down with a graceful arc of their bodies, their large flukes swinging up into the air in a good-bye wave, the black-and-white undersides being the last things seen, as if flashing their nameplates before disappearing. The most dramatic maneuver they showed us, however, was breaching—leaping explosively from the sea, then crashing down with a dreadful smack, splitting the water and momentarily opening up a canyon in the sea!
Breathing, Diving, Birthing
This whale watch whetted my interest to know more. Whales have many specialties. One enables them to breathe while sleeping. Whales breathe through blowholes in the top of their heads. The two tight-fitting lips are closed when relaxed, thus keeping water out of its two small nostrils. To breathe, the whale must voluntarily open its blowholes—breathing is not automatic as in land mammals. This presents a problem during sleep. The whale must order the blowholes to open for each breath. How can it sleep yet breathe? Weinrich answers: “It is now thought that whales and dolphins may sleep with half of their brain at a time, allowing the other half to control voluntary breathing and maintain buoyancy.”
Another special design is for preventing the bends while diving deep. The air in the lungs is compressed under the pressure of the ocean depths, making it possible for nitrogen to leak into the blood. When the whale surfaces, that nitrogen would expand, forming bubbles that would block circulation and cause the bends. To minimize that danger, the whale’s lungs are relatively small, reducing the amount of nitrogen present. Yet, to gain more oxygen the whale exchanges most of the air in its lungs with each breath. People may exchange only 15 to 20 percent in one breath, but the whale exchanges 85 to 90 percent.
Also, the whale stores oxygen differently. People store 34 percent of their oxygen in their lungs, 41 percent in their blood, and only 13 percent in their muscles, plus 12 percent in other tissues. Whales, however, store only 9 percent in their lungs but 41 percent in their muscles, where it is quickly available for use. Of the remaining oxygen, 41 percent is in the blood and 9 percent in other tissues. On a long dive, oxygenated blood is restricted to vital organs. Other body functions are greatly slowed. Incidentally, the sperm whale seems to be the champion diver. It goes down 3,000 feet (910 m) and remains down 90 minutes. Humpbacks go down at most 1,200 feet (370 m).
Birthing in whales is unique. The young are generally born headfirst in mammals, but in whales it must be tailfirst. This is necessary so that a newborn doesn’t inhale underwater and drown. Getting up to the surface for that first breath is the most important minute of that whale’s life. At birth the baby is 10 feet (3 m) long and weighs a ton (900 kg).
“Gentlest of Giants”
“Humpbacks have a reputation for being gentle, but forty tons is forty tons!” With this thought in mind, marine biologist Sylvia Earle apprehensively slipped into the water to meet for the first time humpbacks in their own element. But when one of the graceful giants swept by and its “great eye tilted slightly” to take notice of her, she stopped worrying about encounters with these “gentlest of giants.”
Her sentiments seem to be shared by all. Deborah Glockner-Ferrari, researcher off Maui, in Hawaii, noted the gentleness of the humpbacks, especially expressed between mother and calf: “They are very sensitive to each other. Touching appears to be very important to them. The mother will caress the calf with its flipper. The calf may rest under the mother’s chin.” Jacques Cousteau adds his testimony: “Even among giants, the act of nursing one’s young has an air of tender familial intimacy about it. While the calf is nursing, the mother whale’s flippers play such a large role that they almost seem to be arms cradling the young one. The whale lies on her side and holds the baby with her flippers while he nurses.” And those embracing flippers are 15 feet (4.5 m) long, the biggest among whales.
These gentle giants do get around. They migrate 4,000 to 6,000 miles (6,400 to 9,700 km) annually. Some claim that routes do not always follow set patterns of north-south migrations, that humpbacks border on being nomads. They summer in the cold northern waters of the Atlantic and Pacific oceans, feeding voraciously and putting on layers of blubber. Then off to winter in shallow tropical seas in the Caribbean, Baja California, and Hawaii, busily giving birth, courting, mating, and singing. No eating for months, but
Oh, That Singing!
At night in a small sailboat with his wife, far from land and feeling the loneliness of the sea, Roger Payne lowered a pair of hydrophones into the water, switched on the amplifiers, and listened through the headphones. “We were no longer alone! Instead, we were surrounded by a vast and joyous chorus of sounds that poured up out of the sea and overflowed its rim. The spaces and vaults of the ocean, like a festive palace hall, reverberated and thundered with the cries of whales—sounds that boomed, echoed, swelled, and vanished as they wove together like strands in some vast and tangled web of glorious sound. I felt instantly at ease, all sense of desolation brushed aside by the sheer ebullience of it all. All that night we were borne along by those lovely, dancing, yodeling cries, sailing on a sea of unearthly music.”
There may be singing by a whale soloist, a duet, or a chorus of many voices. Each whale sings the same song but not necessarily in unison with the others. They do not sing mechanically but compose as they go along. The song one year is different from that of other years. This year’s song starts out the same as last year’s, but the whales start improvising and soon the song is entirely new. They are not merely singers, they are composers. Every year a new song—and every whale sings only the new song. They sing only when wintering in warm waters. During the six months of summer, no singing; still, when they resume singing the following season, they use last year’s song to start with—a striking display of their powers of memory!
Although the songs change from year to year, the structure remains the same. All the songs have about six themes, each theme with several identical or slowly changing phrases and each phrase with two to five sounds. Songs by whales in different oceans are different, but all stick to the same structure.
A complete song may last six minutes or half an hour, may be repeated continuously for 24 hours, and may be heard by other whales 20 or 30 miles (30 or 50 km) away. Scientists have said of their songs: “Possibly the most complicated songs in the animal kingdom.” “The most elaborate display in the animal kingdom.”
Divers underwater with the singing whales give their impressions: “Underwater the song was so intense that we could feel the sound as the air spaces in our heads and bodies resonated.” “Heard at close range, the songs are unforgettable—resonant and throbbing.” “The sound was incredible, like drums on my chest.” How the songs are generated is a mystery. Humpbacks have no vocal cords. No bubbles are expelled during the singing. Why they sing is not known, though it is thought it may be in connection with courting and aggressive male behavior. Research indicates that the males are the singers.
The prospect for whales is precarious. Are the humpbacks themselves endangered? Some 100,000 strong a century ago, their ranks have been decimated by whalers. Only 7,000 to 10,000 remain. These marvelous creations butchered for dog and cat food. How sad! Some hope came in 1966: The International Whaling Commission placed them under protection. Did it come too late?
If someday the humpbacks are gone, gone also will be their fishing nets made of bubbles, their 40-ton backflips, their gentle treatment of their own and of man, their journeys without road maps across vast oceans, and gone also will be their wild and eerie songs that once resounded throughout the seas of the earth.
In 1977, Voyagers 1 and 2, launched from Cape Canaveral, carried recordings of the songs of the humpback whales. Is this all that will remain of their songs, to sail silently in outer space for a billion years, heard by no one? Or will the amazing singing whales continue composing and singing their concerts in the seas of the world, to enthrall future generations who will appreciate the many marvelous creatures that grace land and sea? (Psalm 104:24, 25) Only time will tell.—By an Awake! staff writer.
[Pictures on page 16]
Top: The throat pleats balloon out as the water and fish pour in
Bottom: The humpback’s tongue (not shown here) exerts pressure as the pleats contract and the water is expelled, but the small fish remain behind
[Picture Credit Line on page 16]
All photographs in this article by courtesy of Mason T. Weinrich, director of the Cetacean Research Unit, Gloucester, Massachusetts.
[Picture on page 17]
The sea gulls gather for the “crumbs” that fall from the humpback’s table
[Picture on page 18]
Coming up for a bite to eat
[Pictures on page 19]
Top: This is Beltane, recognized by the black-and-white pattern on the undersides of its flukes
Bottom: And this is Mosaic, identified by its flukes, scarred and mutilated by killer whales
[Picture on page 20]
A humpback launching itself upward for a breach
[Picture on page 21]
The mighty flukes of the humpback leave a waterfall as they flip up and disappear into the depths