Links for Keyword: Animal Communication

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Dogs glean information from each other's barks

By Virginia Morell A dog’s bark may sound like nothing but noise, but it encodes important information. In 2005, scientists showed that people can tell whether a dog is lonely, happy, or aggressive just by listening to his bark. Now, the same group has shown that dogs themselves distinguish between the barks of pooches they’re familiar with and the barks of strangers and respond differently to each. The team tested pet dogs’ reactions to barks by playing back recorded barks of a familiar and unfamiliar dog. The recordings were made in two different settings: when the pooch was alone, and when he was barking at a stranger at his home’s fence. When the test dogs heard a strange dog barking, they stayed closer to and for a longer period of time at their home’s gate than when they heard the bark of a familiar dog. But when they heard an unknown and lonely dog barking, they stayed close to their house and away from the gate, the team reports this month in Applied Animal Behaviour Science. They also moved closer toward their house when they heard a familiar dog’s barks, and they barked more often in response to a strange dog barking. Dogs, the scientists conclude from this first study of pet dogs barking in their natural environment (their owners’ homes), do indeed pay attention to and glean detailed information from their fellows’ barks. © 2014 American Association for the Advancement of Science

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 20012 - Posted: 08.30.2014

River turtle mothers 'talk' to their hatchlings

By Victoria Gill Science reporter, BBC News Scientists in Brazil have managed to eavesdrop on underwater "turtle talk". Their recordings have revealed that, in the nesting season, river turtles appear to exchange information vocally - communicating with each other using at least six different sounds. This included chatter recorded between females and hatchlings. The researchers say this is the first record of parental care in turtles. It shows they could be vulnerable to the effects of noise pollution, they warn. The results, published recently in the Journal Herpetologica, include recordings of the strange turtle talk. They reveal that the animals may lead much more socially complex lives than previously thought. The team, including researchers from the Wildlife Conservation Society (WCS) and the National Institute of Amazonian Research carried out their study on the Rio Trombetas in the Amazon between 2009 and 2011. They used microphones and underwater hydrophones to record more than 250 individual sounds from the animals. The scientists then analysed these vocalisations and divided them into six different types, correlating each category with a specific behaviour. Dr Camila Ferrara, of the WCS Brazil programme, told BBC News: "The [exact] meanings aren't clear... but we think they're exchanging information. "We think sound helps the animals to synchronise their activities in the nesting season," she said. The noises the animals made were subtly different depending on their behaviour. For example, there was a specific sound when adults were migrating through the river, and another when they gathered in front of nesting beaches. There was a different sound again made by adults when they were waiting on the beaches for the arrival of their hatchlings. BBC © 2014

Whales and dolphins squeal with delight

By Rebecca Boyle Like a dog wagging its tail in anticipation of treats to come, dolphins and belugas squeal with pleasure at the prospect of a fish snack, according to a new study. It’s the first direct demonstration of an excitement call in these animals, says Peter Madsen, a biologist at Aarhus University in Denmark who was not involved in the study. To hunt and communicate, dolphins and some whale species produce a symphony of clicks, whistles, squeaks, brays, and moans. Sam Ridgway, a longtime marine biologist with the U.S. Navy’s Marine Mammal Program, says he heard distinctive high-pitched squeals for the first time in May 1963 while training newly captured dolphins at the Navy’s facility in Point Mugu, California. “We were throwing fish in, and each time they would catch a fish, they would make this sound,” he says. He describes it as a high-pitched “eeee,” like a child squealing in delight. Ridgway and his collaborators didn’t think much of the sound until later in the 1960s, when dolphins trained to associate a whistle tone with a task or behavior also began making it. Trainers teach animals a task by rewarding them with a treat and coupling it with a special noise, like a click or a whistle. Eventually only the sound is used, letting the animal know it will get a treat later. The whistle was enough to provoke a victory squeal, Ridgway says. Meanwhile, beluga whales would squeal after diving more than 600 meters to switch off an underwater speaker broadcasting tones. “As soon as the tone went off, they would make this same sound,” Ridgway says, “despite the fact that they’re not going to get a reward for five minutes.” He also heard the squeal at marine parks in response to trainers’ whistles. © 2014 American Association for the Advancement of Science.

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 19960 - Posted: 08.14.2014

African Bird 'Cries Wolf' to Steal Food

Fork-tailed drongos, glossy black African songbirds with ruby-colored eyes, are the avian kingdom’s masters of deception. They mimic the alarm calls of other species to scare animals away and then swipe their dupes’ dinner. But like the boy who cried wolf, drongos can raise the alarm once too often. Now, scientists have discovered that when one false alarm no longer works, the birds switch to another species’ warning cry, a tactic that usually does the trick. “The findings are astounding,” says John Marzluff, a wildlife biologist at the University of Washington, Seattle, who was not involved in the work. “Drongos are exceedingly deceptive; their vocabularies are immense; and they match their deception to both the target animal and [its] past response. This level of sophistication is incredible.” Since 2008, Tom Flower, an evolutionary biologist at the University of Cape Town, has followed drongos in the Kuruman River Reserve in the Kalahari Desert. He’s habituated and banded about 200 of the robin-sized birds, and, using food rewards, has trained individuals to come to him when he calls. After getting its snack, the drongo quickly returns to its natural behavior—catching insects and following other bird species or meerkats—while Flower tags along. Drongos also keep an eye out for raptors and other predators. When they spot one, they utter metallic alarm cries. Meerkats and pied babblers, a highly social bird, pay attention to the drongos and dash for cover when the drongos raise an alarm—just as they do when one of their own calls out a warning. Studies have shown that having drongos around benefits animals of other species, which don’t have to be as vigilant and can spend more time foraging. But there’s a trade-off: The drongos’ cries aren’t always honest. When a meerkat has caught a fat grub or gecko, a drongo is apt to change from trustworthy sentinel to wily deceiver. © 2014 American Association for the Advancement of Science.

Dolphin whistle instantly translated by computer

by Hal Hodson Software has performed the first real-time translation of a dolphin whistle – and better data tools are giving fresh insights into primate communication too IT was late August 2013 and Denise Herzing was swimming in the Caribbean. The dolphin pod she had been tracking for the past 25 years was playing around her boat. Suddenly, she heard one of them say, "Sargassum". "I was like whoa! We have a match. I was stunned," says Herzing, who is the director of the Wild Dolphin Project. She was wearing a prototype dolphin translator called Cetacean Hearing and Telemetry (CHAT) and it had just translated a live dolphin whistle for the first time. It detected a whistle for sargassum, or seaweed, which she and her team had invented to use when playing with the dolphin pod. They hoped the dolphins would adopt the whistles, which are easy to distinguish from their own natural whistles – and they were not disappointed. When the computer picked up the sargassum whistle, Herzing heard her own recorded voice saying the word into her ear. As well as boosting our understanding of animal behaviour, the moment hints at the potential for using algorithms to analyse any activity where information is transmitted – including our daily activities (see "Scripts for life"). "It sounds like a fabulous observation, one you almost have to resist speculating on. It's provocative," says Michael Coen, a biostatistician at the University of Wisconsin-Madison. © Copyright Reed Business Information Ltd.

Barn owl nestlings recognise their siblings' calls

Barn owl nestlings recognise their siblings' calls, according to researchers. Instead of competing aggressively for food, young barn owls are known to negotiate by calling out. A team of scientists in Switzerland discovered that the owlets have remarkably individual calls. They suggest this is to communicate each birds' needs and identity in the nest. The findings were announced in the Journal of Evolutionary Biology by Dr Amelie Dreiss and colleagues at the University of Lausanne, Switzerland. Barn owls (Tyto alba) are considered one of the most widespread species of bird and are found on every continent except Antarctica. An average clutch size ranges between four and six eggs but some have been known to contain up to 12. Previous studies have highlighted how barn owl nestlings, known as owlets, negotiate with their siblings for food instead of fighting. While their parents search for food the owlets advertise their hunger to their brothers and sisters by calling out. "These vocal signals deter siblings from vocalizing and from competing for the prey at parental return," explained Dr Dreiss. "If there is a disagreement, they can escalate signal intensity little by little, always without physical aggression, until less hungry siblings finally withdraw from the contest." BBC © 2013

Bird alarm: Great tits use 'predator-specific' calls

By Victoria Gill Science reporter, BBC News Great tits use different alarm calls for different predators, according to a scientist in Japan. The researcher analysed the birds' calls and found they made "jar" sounds for snakes and "chicka" sounds for crows and martens. This, he says, is the first demonstration birds can communicate vocally about the type of predator threatening them. The findings are published in the journal Animal Behaviour. From his previous observations, the researcher, Dr Toshitaka Suzuki, from the Graduate University for Advanced Studies in Kanagawa, found great tits appeared to be able to discriminate between different predators. To test whether they could also communicate this information, he placed models of three different animals that prey on nestlings - snakes, crows and martens - close to the birds' nest boxes. He then recorded and analysed the birds' responses. "Parents usually make alarm calls when they approach and mob the nest predators," said Dr Suzuki. "They produced specific 'jar' alarm calls for the snakes and the same 'chicka' alarm call in response to both the crows and martens," he said. But a closers analysis of the sounds showed the birds had used different "note combinations" in their crow alarm calls from those they had used for the martens. Dr Suzuki thinks the birds might have evolved what he called a "combinatorial communication system" - combining different notes to produce calls with different meanings. Since snakes are able to slither into nest boxes, they pose a much greater threat to great tit nestlings than other birds or mammals, so Dr Suzuki says it makes sense that the birds would have a specific snake alarm call. BBC © 2013

Wag the dog: When left vs. right matters

by Bethany Brookshire Most of us see a wagging dog’s tail and think it’s got to be a good sign. Wagging = welcome, right? Especially if it’s the kind of wag that’s knocking over small items. But it turns out that not all wags are equal, and some are a lot more welcoming than others. When I walked into my college biology course freshman year, we started out with a discussion of symmetry. Most animal are built with some symmetry, either radial or bilateral — radial like a starfish, bilateral like a human. Symmetry means things, like health or attractiveness. But it turns out that asymmetry can mean things too. And an asymmetrical behavior might mean some important things for dogs. Marcello Siniscalchi of the University of Bari Aldo Moro in Italy and colleagues decided to look at asymmetry in dog wags. They noticed that sometimes, dogs wag more to the right, usually when seeing their owner or something else happy. They wag more to the left when they see something like a dominant or unfamiliar dog. So the wag itself could represent the emotional state of the dog doing the wagging. But can the dogs seeing the wagging (the wagees) tell the difference? In a paper published October 31 in Current Biology, the authors found that they can. They used videos of a real dog or the silhouette of a dog wagging to the right (the wagging dog’s right, by the way) or to the left, and examined 43 other dogs as they watched (OK, they started with 56, but 13 didn’t pay attention), to see how the wagee reacted. The observing dogs wore a vest to monitor their heart rate, and were videotaped so behaviorists could look at their behaviors afterward. © Society for Science & the Public 2000 - 2013.

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 11: Emotions, Aggression, and Stress
Link ID: 18864 - Posted: 11.02.2013

Mama bird tells babies to shut up, danger is near

Sending up the alarm when a predator approaches seems like a good idea on the surface. But it isn’t always, because such warnings might help the predator pinpoint the location of its next meal. So animals often take their audience into account when deciding whether or not to warn it of impending danger. And a new study in Biology Letters finds that the vulnerability of that audience matters, at least when we’re talking about baby birds and their parents. Tonya Haff and Robert Magrath of Australian National University in Canberra studied a local species, the white-browed scrubwren, by setting up an experiment to see if parents' reactions to predators changed when the babies were more vulnerable. Baby birds are vulnerable pretty much all the time but more so when they’re begging for food. That whining noise can lead a predator right to them. But a parent’s alarm call can shut them right up. Haff and Magrath began by determining that parent scrubwrens would respond normally when they heard recordings of baby birds. (They used recordings because those are more reliable than getting little chicks to act on cue.) Then they played those recordings or one of background noise near scrubwren nests. The role of the predator was played by a taxidermied pied currawong, with a harmless fake crimson rosella (a kind of parrot) used as a control. The mama and papa birds called out their “buzz” alarm more often when the pied currawong was present and the baby bird recording was being played. They barely buzzed when the parrot was present or only background noise was played. The parents weren’t alarm calling more just to be heard over the noise, the researchers say. If that were the case, then a second type of call — a contact “chirp” that mamas and papas give when approaching a nest — should also have become more common, which it didn’t. © Society for Science & the Public 2000 - 2013.

Monkey's alarm calls reveal predator location

Ed Yong Listen very carefully in the rainforests of Brazil and you might hear a series of quiet, high-pitched squeaks. These are the alarm calls of the black-fronted titi (Callicebus nigrifrons), a monkey with a rusty-brown tail that lives in small family units. The cries are loaded with information. Cristiane Cäsar, a biologist at the University of St Andrews, UK, and her colleagues report that the titis mix and match two distinct calls to tell each other about the type of predator that endangers them, as well as the location of the threat. Her results are published in Biology Letters1. Cäsar's team worked with five groups of titis that live in a private nature reserve in the Minas Gerais region of Brazil. When the researchers placed a stuffed caracara — a bird of prey — in the treetops, the titis gave out A-calls, which have a rising pitch. When the animals saw a ground-based threat — represented by an oncilla, a small spotted cat — they produced B-calls, sounds with a falling pitch. However, when the team moved the predator models around, the monkeys tweaked their calls. If the caracara was on the ground, the monkeys started with at least four A-calls before adding B-calls into the mix. If the oncilla was in a tree, the monkeys made a single introductory A-call before switching to B-calls. “A single call doesn’t really tell the recipient what’s happening, but they can infer the type of predator and its location by listening to the first five or six calls,” says co-author Klaus Zuberbühler of the University of Neuchâtel in Switzerland. “The five different groups were almost unanimous in their response. There was no deviation.” © 2013 Nature Publishing Group

Decoding the Call of the Wild

Virginia Morell A wolf’s howl is one of the most iconic sounds of nature, yet biologists aren’t sure why the animals do it. They’re not even sure if wolves howl voluntarily or if it’s some sort of reflex, perhaps caused by stress. Now, scientists working with captive North American timber wolves in Austria report that they’ve solved part of the mystery. Almost 50 years ago, wildlife biologists suggested that a wolf’s howls were a way of reestablishing contact with other pack members after the animals became separated, which often happens during hunts. Yet, observers of captive wolves have also noted that the pattern of howls differs depending on the size of the pack and whether the dominant, breeding wolf is present, suggesting that the canids’ calls are not necessarily automatic responses. Friederike Range, a cognitive ethologist at the University of Veterinary Medicine in Vienna, was in a unique position to explore the conundrum. Since 2008, she and her colleagues have hand-raised nine wolves at the Wolf Science Center in Ernstbrunn, which she co-directs. “We started taking our wolves for walks when they were 6 weeks old, and as soon as we took one out, the others would start to howl,” she says. “So immediately we became interested in why they howl.” Although the center’s wolves don’t hunt, they do howl differently in different situations, Range says. “So we also wanted to understand these variations in their howling.” © 2012 American Association for the Advancement of Science.

Shhh, the Ants Are Talking

by Carrie Arnold If you want to survive as an ant, you'd better get ready to make some noise. A new study shows that even ant pupae—a stage between larvae and adult—can communicate via sound, and that this communication can be crucial to their survival. "What's very cool about this paper is that researchers have shown for the first time that pupae do, in fact, make some sort of a sound," says Phil DeVries, an entomologist at the University of New Orleans in Louisiana who was not involved in the study. "This was a very clever piece of natural history and science." Scientists have known for decades that ants use a variety of small chemicals known as pheromones to communicate. Perhaps the most classic example is the trail of pheromones the insects place as they walk. Those behind them follow this trail, leading to long lines of ants marching one by one. However, the insects also use pheromones to identify which nest an ant is from and its social status in that nest. Because this chemical communication is so prevalent and complex, researchers long believed that this was the primary way ants shared information. However, several years ago, researchers began to notice that adults in some ant genuses, such as Myrmica, which contains more than 200 diverse species found across Europe and Asia, made noise. These types of ants have a specialized spike along their abdomen that they stroke with one of their hind legs, similar to dragging the teeth of a comb along the edge of a table. Preliminary studies seemed to indicate that this noise served primarily as an emergency beacon, allowing the ants to shout for help when being threatened by a predator. © 2010 American Association for the Advancement of Science

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 4: Development of the Brain
Link ID: 17779 - Posted: 02.09.2013

Injured Dolphin Seeks Help from Diver

by Tracy Staedter In this sweet video, a wild bottlenose dolphin slowly approaches a diver, who is with a group that’s watching manta rays near Kona, Hawaii. The dolphin rolls to one side, apparently showing the diver, named Keller Laros, that it’s tangled in fishing net and has a hook stuck in its fin. According to Yahoo News, the dolphin surfaced once for a breath air during the procedure and then returned to the diver, who finished the job of cutting away the net and removing the hook. Once the dolphin was free, it swam away. © 2013 Discovery Communications, LLC

Birdsong Not Music, After All

by Emily Underwood In the Hans Christian Andersen tale "The Nightingale," a songbird melts an emperor's heart with its singing, but flies away when the ruler forces it to sing duets with a jeweled, mechanical bird that warbles only waltzes. There's a moral here, a new study suggests. Although humans have long attributed musical qualities to birdsong, cold, hard statistics show that's all an illusion. The birds we prize most for their songs sound most like the human voice, says Robert Zatorre, a cognitive neuroscientist at McGill University in Montreal, Canada, who was not involved in the study. The sounds they make have clear tones, repeat similar phrases, and are made of discrete notes. Despite these pleasing attributes, however, it has never been scientifically proven that the notes in birdsong follow the same organizational rules that govern most musical compositions. In fact, says ecologist Marcelo Araya-Salas of New Mexico State University in Las Cruces, author of the new study, no one has ever addressed the question using quantitative methods. Billions of potential notes exist between the low and high notes in an octave. But for reasons that researchers only partially understand—the physiological limits of human hearing, for example, and cultural preferences that have evolved over time—most music is based on variations of only five to 12 notes. A baby grand piano, which has 88 keys, is tuned so that each octave is divided into twelve equal intervals, called half-steps, that form the 12-note chromatic scale underlying most of Western music. The seven-note diatonic scale, "do, re, mi, fa, so, la, ti (do)," is another familiar example, as is the ancient five-note, pentatonic scale used in Greek lyre music and nearly every riff played on the electric guitar. © 2010 American Association for the Advancement of Science

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 17172 - Posted: 08.16.2012

In a Chorus of Bleats, One That Sounds Familiar

By SINDYA N. BHANOO If you’ve heard one pygmy goat kid bleating, you’ve heard them all — unless, that is, you’re a mother goat. A new study reports that mothers can recognize the calls of their kids even after more than a year of separation. In the wild, female goats tend to stay within their groups, while males disperse. For their study, researchers separated the goats after weaning, and found that the mothers remembered the calls of their offspring for 7 to 13 months. The study appears in the journal Proceedings of the Royal Society B. “Mothers responded more to their kids born the previous year than to newborn kids born to other mothers,” said Elodie F. Briefer, an evolutionary biologist at Queen Mary, University of London, and one of the study’s authors. Dr. Briefer and her colleagues recorded kids when they were 5 weeks old, and played the recordings back to the mothers through a loudspeaker later. It isn’t clear why mother goats have this ability, but it could help mothers and daughters stay bonded and prevent mothers from inbreeding with their sons, Dr. Briefer said. “These functions would happen later in life, but the mothers would need to recognize their grown-up kids,” she said. The researchers worked with nine female pygmy goats and their kids at a farm in Nottinghamshire, England. They measured how quickly the goats responded to recorded calls, how many calls they made in response to what they heard, and how long they looked at the loudspeaker. © 2012 The New York Times Company

Chicks do worse in noisy nests

By Susan Milius ALBUQUERQUE — Baby bluebirds don’t survive as well near rumbling traffic and other human din as they do amid natural lullabies. In a Virginia study, 35 percent more chicks died in the noisiest nests than in the most remote ones. Researchers found that chicks didn’t adjust for the noise by begging louder or at different frequencies. So parents may not have gotten the right cues for nestling care, behavioral ecologist John Swaddle suggested June 12 at the annual meeting of the Animal Behavior Society. Until recently, most research on how human-made noise discombobulates birds has focused on how adults adjust their songs (or don’t) or on what species will nest at all among the din. Research is now turning to how noise might directly affect the success of a species. One earlier study on reproductive success, in common European birds called great tits, found smaller clutches near roaring highways. Clutch size didn’t shrink among eastern bluebirds (Sialia sialis), said Swaddle, a professor at the College of William and Mary in Williamsburg, Va. Birds settling in to the 43 nest boxes he and his colleagues monitored for two years all started with about the same number of eggs. Just what made noisier nests less successful after hatching isn’t clear, but Swaddle suspects that noise kept parents from caring for their nestlings properly. Noise might have made food harder to find, or it might have masked normal parent-chick chat. Even though baby birds have become an icon of endlessly demanding maws, parents do tune their feeding effort to begging calls, and research has confirmed the importance of communication. © Society for Science & the Public 2000 - 2012

Related chapters from BN: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 16926 - Posted: 06.19.2012

More to Learn About Dolphin Whistles

By TARA THEAN Instead of spending the morning loading equipment onto boats and conceptualizing our follow strategy for the day, we spent it cleaning our motel rooms and preparing to leave. We enjoyed winding down at the farewell barbecue last night. The weather was perfect for a cookout: warm and slightly breezy. I particularly enjoyed eating my first hot meal in five days: two burgers and a hot dog. Our packed lunches on the boat had to be portable, sturdy and compact, which means our lunchboxes were filled with sandwiches and cereal bars. By dinnertime, I was always so exhausted that I couldn’t bring myself to eat more than cereal and milk. After we had settled down with food, our program director, Randall Wells, gave us a final debriefing about the week’s work. I was happy to hear that we had sampled and examined 16 dolphins in this round of fieldwork — in a typical field week, we find 10 to 15. Of these 16, four were high-priority animals that we had previously not had a chance to look at: FB274, FB233, FB276 and Boomer. I also found out that one of the dolphins we had thought was female was actually male — thankfully, he had been given the versatile name Pat. We needed plenty of teamwork and persistence to take us through the long, unpredictable days in the field. But even in the revelry of the farewell party, we had work left to do. In the evening, my supervisor, Laela Sayigh, and I hosed down the field gear for storage over the next few months and organized equipment back at the Sarasota Dolphin Research Program base. © 2012 The New York Times Company

Nice to Meet eet eet You

by Elizabeth Norton Bottlenose dolphins have a knack for language. They can understand both the meaning and the order of words conveyed through human hand gestures—correctly putting an item on the right side of their tank into a basket on the left, for example. Now humans, too, are beginning to understand dolphin language as more than just a cacophony of clicks, pulses, and whistles. A new study shows that dolphins use their own unique calls, known as signature whistles, to introduce themselves to others when meeting at sea. Until recently, researchers could study signature whistles only in captive animals—raising the question of whether the whistle developed in response to capture, isolation, or stress. A 2004 study showed that a group of free-swimming bottlenose dolphins in Florida did indeed use signature whistles. But information about how they used these sounds was scant. Marine biologists Vincent Janik and Nicola Quick of the Sea Mammal Research Unit at the University of St. Andrews in the United Kingdom were focusing on signature whistles as a way of understanding how dolphins communicate in the natural world. "Dolphins are comparable to great apes in their cognitive skills, but all we know is what they do in a lab," Janik explains. "We wanted to understand how dolphins use their intelligence outside of the tasks that humans set for them." © 2010 American Association for the Advancement of Science.

Can You Hear Me Now? Human Noise Disrupts Blue Whale Communication

By Jason G. Goldman When you dive into the frigid waters of the Pacific Ocean off the coast of southern California, the first thing you notice is the silence. Other than the bitter cold. Your body begins to adapt to the chilly water as blades of slimy kelp brush across your ankles. You spit out the bit of brackish saltwater that inevitably seeps into your mouth. Then you quickly dunk your head into the sea so that you might wet your hair and wipe it away from your eyes. It’s in that moment – when you’re entirely submerged under the rolling waves – that you notice the silence. You can almost hear the oscillating thuds of the waves breaking against the sand. As your heart beats faster to push warm blood into your arms and legs, perhaps you might even be able to hear your own heartbeat. Even against the auditory backdrop of the pounding of the waves and your heart, you can’t help but perceive the quiet. If only it were so for the blue whales that call this corner of the ocean home, at least for part of the year. Each summer, groups of endangered blue whales (Balaenoptera musculus) pass along the coast of Southern California between San Diego and Los Angeles. It isn’t a secret that the ocean is a noisy place if you’re a whale. In addition to the natural soundscape of the ocean, whales can hear sounds that have human origins, like sonar, passing ships, or underwater explosions. Considerable scientific attention has been paid to the effects of high-intensity anthropogenic noise on the communication abilities of whales and other marine mammals. After all, these animals communicate over vast distances by producing clicks, whistles, and songs. Previous findings have confirmed that the presence of ships interrupts blue whale songs. And some whales have been observed increasing the amplitude of their foraging calls in noisy environments, in an effort to aid others in distinguishing their communication from the undersea cacophony. Imagine having to pick out the sounds of only the cellos from amid an entire orchestra. © 2012 Scientific American

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 15: Language and Lateralization
Link ID: 16457 - Posted: 03.01.2012

Humpback whales’ songs differ from one side of Indian Ocean to the other

By Juliet Eilperin, Humpback whales on different sides of the southern Indian Ocean are singing different songs, according to a new study conducted by American and Australian researchers. The report challenges the past assumption that whales in the same ocean basin sing songs with similar themes. The humpback songs were recorded during the 2006 breeding season along the coasts of western Australia and Madagascar. The analysis was published in the January edition of the journal Marine Mammal Science. “Songs from Madagascar and western Australia only shared one similar theme; the rest of the themes were completely different,” said lead author Anita Murray, who is pursuing her doctorate at the University of Queensland in Australia. “The reason for this anomaly remains a mystery. It could be the influence of singing whales from other ocean basins, such as the South Pacific or Atlantic, indicating an exchange of individuals between oceans which is unique to the Southern Hemisphere.” The findings could provide new insight into how whale culture spreads. Male humpback whales are generally the ones that sing. The songs include rising and falling wails, moans and shrieks that repeat in cycles lasting up to half an hour. Researchers suspect that individuals from different humpback populations could transmit songs to one another when they are share feeding grounds or cross paths during migration. © 1996-2012 The Washington Post

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