Science / Medicine : Inscrutable Hulks : Biology: Among the many puzzling questions about whales, the most urgent is how long these leviathans can survive the buildup of toxic pollutants in the oceans.
In the 1960s, U.S. military officials became alarmed when newly improved underwater microphones picked up strange, booming noises under the ocean’s surface. The bass notes were very loud, unusually low in frequency (about 20 cycles per second), lasted for only a few seconds and displayed complicated patterns.
The Navy thought that perhaps the Soviet Union had devised a new way to detect the movement of U.S. submarines using a technique similar to that employed in some home burglar alarms--in which movement through an inaudible sound pattern in a room triggers an alarm. So the Navy commissioned Bell Laboratories to find the source of the noise.
To their astonishment, the researchers found that the noises were not being produced by Soviets but by fin whales, leviathans of the deep. The whales make an unusually loud sound, “about 155 decibels, the equivalent of standing next to a jet engine at full throttle,” said biologist Roger Payne, director of the Whale and Dolphin Conservation Society.
Because of the way sound is transmitted in the ocean, he added, the call of the fin whale can be heard for hundreds of miles. In earlier times, before humans started cruising the seas with noisy ships, the whales could have been heard for thousands of miles. A whale off the coast of New England could hear the call of a whale off the coast of England.
Perhaps even more astonishing, Payne said, the whales make their awesome noise without releasing any air. (Try that yourself sometime.)
How whales sing--either the simple calls of the fin whales or the complex, hauntingly beautiful melodies of the humpback--is but one of the mysteries that surrounds this unusual family, which includes the common dolphin and the massive blue whale, the largest creature that ever existed. Even more puzzling is why whales sing, or why they have brains that are larger than humans’ and equally complex. “We have not the tiniest, tiniest notion of what they use their brain for,” Payne said.
But most perplexing of all is the question of how long whales will persist on Earth. With the exception of Japan, nations around the world have abandoned whaling. Strong progress is being made against the use of drift nets and purse seines by commercial fishermen. But these victories may be illusory.
“In the end, the most serious threat to these creatures is not harpoons, not even the drift nets which wrongfully trap them, but rather the prolonged accumulation of toxic pollutants in the ocean,” Payne said. “We have to respond to the warning the whales are giving us about the oceans and we have to cease business as usual.”
Payne, widely regarded as the world’s leading cetacean conservationist and research scientist, has dedicated his life to probing the mysteries of whales. Recently he talked with The Times about his research and recent advances in knowledge about whales.
Payne originally studied bats, owls and moths, but became dissatisfied “because my work didn’t seem relevant to what I felt were the huge problems facing wildlife today.” He became interested in whales “when I realized that nobody was focusing on their protection. Yet whales were . . . practically extinct--at least certain species of them.”
Payne came to public attention in 1967 when he and Scott McVay discovered the intricate songs of the male humpback whales. These songs, researchers now know, follow the same rules of composition as human music, including such features as rhyme.
It was once thought that the songs might be used to convey information, but that now seems unlikely. Humpbacks thousands of miles apart sing the same song, and the song changes very slowly, requiring a full seven years to become renewed. “If they’re conveying information, it’s going to get pretty monotonous,” Payne said.
Although scientists still do not know the significance of the songs, the fact that the males sing only during mating season suggests that they sing to attract females. “My own personal theory is that it’s a measure of fitness,” Payne said. “The male who can stay underwater singing for the longest time is the fittest.” On average, they sing for about 20 minutes without breathing.
But Payne’s primary area of expertise is the right whale, which he has been studying for 23 years. He has found that right whales return every winter to a bay at Argentina’s Peninsula de Valdes and he has observed them at length. Such study, he hopes, will allow researchers to help the right whale increase its numbers, as well as shed light on the future of humans.
The right whale is a baleen whale. Instead of having teeth--like the sperm whale, dolphin and killer whale--that allow it to eat fish and squid, it has baleen, a bony filter that grows down from the upper gum and permits it to strain shrimp-like krill and other small organisms from the water. But they do not feed unless the krill is present in very high concentrations because “eating costs more than it gains,” Payne said.
Because they eat so seldom, whales need large energy stores--their blubber. The blubber does not, as many people believe, serve to keep them warm. In fact, whales generate so much heat internally that they frequently have to dive into deep, cold waters to cool off.
Right whales were nearly hunted into extinction because they are the only whale that floats when dead, making harvesting easier. Their name comes from the fact that rookie whalers would point at them and ask, “Is that the right whale?” The name stuck.
They are making a comeback since whaling has come into disfavor. Payne knows more than 1,000 right whales by sight--they are recognizable by the arrangement of wart-like growths on their skin called callosities.
Payne has been particularly interested in their reproductive practices in hopes of uncovering information that might assist in that comeback. He quickly found that they give birth only every three years or so--”a surprisingly long time” that partially explains their slow recovery.
Females are “absolutely promiscuous,” mating with large numbers of males for reasons that are not clear, Payne said. And the males practice what he terms “reciprocal altruism,” helping each other to mate. Without such cooperation, he added, their reproductive success would be much lower.
When a female wants to resist a male, she will roll upside down in the water so the male cannot reach her genital area. But she can only remain rolled over for about 20 minutes, at which time she must right herself to breathe.
Two males in a breeding pack will position themselves on each side of the female, so that she cannot readily escape when she rights herself. A third will wait underwater and seize the opportunity when she does. Such assisted mating is unique to whales, Payne said.
The greater mystery about right whales, and others as well, is their large brains. Some researchers have suggested that whales use them for echolocation of objects in their environment and on the sea floor. But bats do that with a brain smaller than a walnut, Payne said, so there must be some other, as yet unknown, function for it.
Why? “Because brains are extremely expensive things to maintain and operate. During the first few weeks of life of a human being, whose brain-to-body ratio is similar to that of a newborn dolphin, the brain requires about a third of the metabolism of the whole body just to run it . . . So you don’t just kind of end up having a fancy brain. You have a fancy brain because there is a compelling reason that you need a fancy brain.”
Payne’s greatest concern now is the encroachment of pollutants into the ocean, particularly such persistent industrial chemicals as PCBs and PBBs. These chemicals are nearly insoluble in water, but are highly soluble in the fat of plants and animals. They work their way up the food chain, reaching high concentrations in whales.
Researchers have recently found beluga whales with a concentration of PCBs and PBBs of 3,200 parts per million and bottle-nosed dolphins with a concentration of more than 6,900 p.p.m.
In contrast, the U.S. government considers materials containing more than 50 p.p.m. a hazard. “If you drag a beached porpoise into the ocean, you could receive a $10,000 fine” for improper disposal of polluted materials, Payne said.
At low concentrations, these materials interfere with reproductive ability and fetal development, producing “appalling” birth defects, he said. At higher concentrations, the chemicals produce an AIDS-like disorder, impairing the animals’ immune function and leaving them vulnerable to disease.
In recent years, hundreds of thousands of whales and dolphins have died from diseases that would not normally be fatal to healthy individuals.
Payne is concerned not only for the whales, but because the pollutants affect humans as well. “The truth is we are in the middle of a war. We just don’t know it yet. It’s a war with ourselves, and where the weapons of our destruction are our own practices which destroy the environment. Once we recognize that, then we can do something about it, but not until we recognize it.”
Payne will host a new documentary film, “In the Company of Whales,” which will appear on the Discovery Channel in April.
