Links for Keyword: Animal Communication

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by Sara Reardon Péos, Mininos, Cécil, Teha, and Amtan are performing dolphins at the Planète Sauvage dolphinarium in Port-Saint-Père, France. Every day, as music and sounds of the sea play in the background, they show off their swimming, jumping, and ball-catching skills for an adoring audience and squawk and whistle just like dolphins should. But at night, they make strange noises that researchers believe are imitations of humpback whale songs included in the performance soundtrack. If so, the identification of this unexpected repertoire would mark the first time that dolphins have been heard to rehearse new sounds hours after hearing them rather than right away, providing insights into how they store and process memories. Researchers discovered the dolphins' midnight melodies by accident. Ethologist Martine Hausberger of the University of Rennes 1 in France and her colleagues had hung underwater microphones in the tank because little is known about what dolphins sound like at night. One night, they suddenly heard 25 new sounds (see below) that the dolphins had never made before, although they weren't sure which of the five animals was talking. Because dolphins are known for mimicry, the researchers examined their complex daytime environment to determine where the noises might be coming from. They finally zeroed in on the new soundtrack that Planète Sauvage was playing during performances, which included music, sea gulls' calls, the dolphins' own whistles, and humpback whale calls. When the researchers used a computer program to compare auditory recordings of the whale calls with the mysterious nighttime noises, it showed that the two sounds were very similar. And because the dolphins had been captive their entire lives, they couldn't have picked them up from real whales. © 2010 American Association for the Advancement of Science.

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 10: Biological Rhythms and Sleep
Link ID: 16280 - Posted: 01.21.2012

The Call of the Wild

By C. CLAIBORNE RAY Q. How do deer communicate? Do they have any ability to vocalize? A. As both hunters and zoologists know, deer have many means of communication, and vocalizations are an important part of their repertory. “Deer vocalizations are also notable for their diversity, ranging from doglike ‘alarm’ barks to high-pitched, whistlelike mating bugles,” according to a 2003 review article in the journal Advances in the Study of Behavior. The occasions for deer conversations vary by species, the article says, but include social contact, interactions between mother and young, encounters with predators and especially the complex negotiations involved in mating. An expert on hunting white-tail deer, T. R. Michels, offered a list of deer signals in his “Whitetail Addicts Manual” (Creative Publishing International). Among them are foot stomping, tail flagging, head bobbing, ear twitching, hoof pawing and nose licking; lunges, charges, chases, pokes and antler thrusts; and aggressive sounds he describes as grunt-snorts and grunt-snort-wheezes. There are also alarm snorts and bawls and less disturbing sounds, like social-contact grunts between does. Deer have a variety of glands that produce strongly scented hormonal signals. The vomeronasal organ detects hormones and other chemicals in urine with a characteristic intake of breath called the flehmen sniff. C. CLAIBORNE RAY © 2012 The New York Times Company

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: 16212 - Posted: 01.03.2012

Singing Whales Steal Spotlight From Earthquakes

by Helen Shen SAN FRANCISCO, CALIFORNIA—Underwater earthquake recordings could help track the endangered and poorly understood fin whale, according to research presented here last week at the annual meeting of the American Geophysical Union. Most quake researchers cull the whale's booming calls from their seafloor recordings. But one group of seismologists has flipped things around to harvest an extensive repertoire of fin whale songs. The second-largest among whales, fin whales (Balaenoptera physalus) live in many of the world's oceans. Yet, relatively little is known about their social habits, breeding grounds, and seasonal migration paths. The animals stick mostly to deep waters far offshore, so following them by visual surveys and radio tagging can be difficult and costly. Seismologist William Wilcock of the University of Washington, Seattle, wondered if there was a better way. From 2003 to 2006, his group had measured undersea earthquakes that occur as new sea floor forms. Implanted in the ocean floor, their seismic detectors also picked up fin whale calls, which—at 17 to 35 hertz—overlap in frequency with Earth's rumblings. To extract earthquake information efficiently, the group developed computer programs to detect and filter out whale songs. Using a similar strategy to weed out seismic vibrations brought the singing whales to center stage. "We just turned the code around," says Dax Soule, a graduate student in Wilcock's lab. In 3 years, the researchers recorded about 300,000 fin whale calls near the Endeavour hydrothermal vents on the Juan de Fuca Ridge, near Vancouver Island in Canada. © 2010 American Association for the Advancement of Science.

How Far Will Dolphins Go to Relate to Humans?

By ERIK OLSEN OFF THE BAHAMAS — In a remote patch of turquoise sea, Denise L. Herzing splashes into the water with a pod of 15 Atlantic spotted dolphins. For the next 45 minutes, she engages the curious creatures in a game of keep-away, using a piece of Sargassum seaweed like a dog’s chew toy. Dr. Herzing is no tourist cavorting with marine mammals. As the world’s leading authority on the species, she has been studying the dolphins for 25 years as part of the Wild Dolphin Project, the longest-running underwater study of its kind. “I’m kind of an old-school naturalist,” she said. “I really believe in immersing yourself in the environment of the animal.” Immerse herself she has. Based in Jupiter, Fla., she has tracked three generations of dolphins in this area. She knows every animal by name, along with individual personalities and life histories. She has captured much of their lives on video, which she is using to build a growing database. And next year Dr. Herzing plans to begin a new phase of her research, something she says has been a lifetime goal: real-time two-way communication, in which dolphins take the initiative to interact with humans. Up to now, dolphins have shown themselves to be adept at responding to human prompts, with food as a reward for performing a task. “It’s rare that we ask dolphins to seek something from us,” Dr. Herzing said. © 2011 The New York Times Company

Dolphins call each other by name

by Michael Marshall Dave the dolphin whistles, and his friend Alan whistles back. We can't yet decipher their calls, but some of the time Dave may be calling: "Alan! Alan! Alan! Alan!" Stephanie King of the University of St Andrews, UK, and colleagues monitored 179 pairs of wild bottlenose dolphins off the Florida coast between 1988 and 2004. Of these, 10 were seen copying each other's signature whistles, which the dolphins make to identify themselves to each other. The behaviour has never been documented before, and was only seen in pairs composed of a mother and her calf or adults who would normally move around and hunt together. The copied whistles changed frequency in the same way as real signature whistles, but either started from a higher frequency or didn't last as long, suggesting Dave was not merely imitating Alan. Copying only happened when a pair had become separated, which leads King to speculate that they were trying to get back together. She believes the dolphins were mimicking another animal's whistle as a way of calling them by name. King presented her research last week at the summer conference of the Association for the Study of Animal Behaviour in St Andrews. Justin Gregg of the Dolphin Communication Project in Old Mystic, Connecticut, remains cautious, and points out that the dolphins may copy the signature whistles simply because they hear them a lot. © Copyright Reed Business Information Ltd.

Why Do Hyenas Laugh?

By KAY E. HOLEKAMP We had just started our afternoon “obs” a few days ago when we found three adult hyenas, all high-ranking females, sleeping on an open hillside. Then we saw something they hadn’t yet noticed: a very large male African cape buffalo that appeared to be dying. We could see from his worn teeth that he was very old, and though he could move his legs, he couldn’t seem to lift his head. One thing about studying large carnivores is that feeding can be difficult to watch. Although hyenas quickly kill smaller prey like gazelle by crushing the neck or skull, they tend to take down larger animals by disembowelment, letting their target bleed out, but that can take some time. We always hope the prey animal is in shock while this is happening, as there would be nothing we could do to speed up the prey animal’s death in any case. As the poet Tennyson put it, nature really is “red in tooth and claw.” Eventually the three females got up from their nap and noticed the buffalo. They were silent as they approached it, avoiding its flailing limbs as they began to tear off pieces of flesh with their sharp teeth. When the dying animal bellowed in pain, its herd-mates rushed over and charged the hyenas, which scattered but then approached again to continue feeding. Still the hyenas were silent, suggesting either that they needed no help to subdue the prey or that they preferred not to share it with their clan mates. However, as often happens, other hyenas apparently heard the cries of the dying buffalo, and started appearing from all directions. The arriving clan members were all very excited to see roughly 1,500 pounds of fresh food already brought to ground! It was not until cubs that had recently graduated from the communal den began arriving at this kill site that we started to hear hyena voices. As each youngster arrived at the scene, it was clearly overwhelmed with excitement and nervousness. This could easily be seen in their body postures, their bristled tails and most of all in their voices. They grinned and groveled before their larger clan mates, and produced many loud “whoop” vocalizations. © 2011 The New York Times Company

Crows tell the world who's bad

by Michael Marshall If you've ever wondered what crows are saying when they caw at a perceived threat from the treetops, here is a sample: "I'm telling on you!" By watching who their neighbours and parents scold, one group of crows has learned to recognise and scold a dubious human. John Marzluff of the University of Washington in Seattle discovered five years ago that crows can recognise individual humansMovie Camera who posed a threat. He briefly trapped American crows (Corvus brachyrhynchos) on his university's campus while wearing a distinctive "caveman" mask. Afterwards, crows that had been trapped scolded anyone they spotted wearing the caveman mask, following them around and cawing harshly, but studiously ignored people wearing a neutral mask. Since then Marzluff has been monitoring the birds' response to the masks. Tests in which researchers toured the campus wearing masks showed that more and more crows had taken to scolding people sporting the caveman mask. Two weeks after the trapping, 26 per cent of crows scolded people wearing the offending mask, but 2.7 years later a remarkable 66 per cent did so. In the fifth year of the study, Marzluff barely got 50 metres out of his office in the caveman mask before a mob of crows started scolding him. The behaviour also gradually spread outwards from the original trapping site. © Copyright Reed Business Information Ltd

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 15513 - Posted: 06.30.2011

Sperm whale 'dialects' linked to distinct cultures

Sperm whales speak in distinct regional dialects that appear closely linked to different "cultural groups," a Canadian researcher says. "The animals in the Caribbean sound different than the animals in the Pacific — even the Gulf of Mexico, which is right beside the Caribbean," said Shane Gero, a researcher at Dalhousie University in Halifax. "In a lot of ways, that's very similar to us. We can identify someone from the U.K. versus Canada because they say 'lorry' and not 'truck.'" Sperm whales from many different regions meet in some "multicultural" areas of the ocean but tend to associate with whales that speak their own dialect, Gero told CBC's Quirks & Quarks in an interview that airs Saturday. "Their society really is divided based on culture," he said. "Animals that have different dialects behave differently. They feed on different things. They raise their babies differently." Gero has been studying sperm whales in the Caribbean for his PhD thesis. He and his collaborators in Canada and Scotland have been trying to decode sperm whale language by recording the voices of pairs of animals talking to one another and noting differences among the sounds they make. Female sperm whales spend all year in family groups in subtropical regions of the ocean, while males roam all over the world. When two whales encounter each other, they make patterns of clicks called codas. © CBC 2011

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 0: ; Chapter 15: Language and Lateralization
Link ID: 15353 - Posted: 05.21.2011

Animals Make Friends, Too

By Jennifer Viegas As Valentine's Day cards attest, humans value love and friendship that aren't just forged by family ties, common interests or sexual attraction. Now researchers have determined that such human-like friendships exist among at least five different types of animals. Prior studies determined that elephants, dolphins, some carnivores and certain non-human primates, such as chimpanzees, have the ability -- just as humans do -- to maintain enduring friendships in highly dynamic social environments. A new study, published in the latest issue of the Proceedings of the Royal Society B, adds bats to that list. Female wild Bechstein's bats prefer to literally hang out with certain friends while they also keep loose ties to the rest of their colony. Lead author Gerald Kerth told Discovery News that these bat buddies mirror human ones. Despite all of their "daily chaos, the bats are able to maintain long-term relationships," he said. "We do not work, play and live together with the same individuals all the time during the day and week," he explained. "But nevertheless, we are able to maintain long-term relationships with our friends and our family despite our often chaotic and highly dynamic social lives." Kerth, a professor at the University of Greifswald's Zoological Institute, and colleagues Nicolas Perony and Frank Schweitzer monitored colonies of the bats over a period of five years. Male bats of this species are solitary, but females roost together in bat boxes and tree cavities. They preferred certain companions over the years. © 2011 Discovery Communications, LLC.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 0:
Link ID: 14978 - Posted: 02.10.2011

Blindfolded dolphin mimics its mates

Sandrine Ceurstemont, Dolphins keep amazing people with their clever tricks. Now it seems they can even copy the moves of others without needing to see them (see video above). A team at the Dolphin Research Center in Grassy Key, Florida, conducted the first experiment with blindfolded dolphins to investigate how they imitate others. Although they are known to mimic sounds and actions, it's unclear exactly what senses they use to do this. A dolphin called Tanner that had previously been trained to imitate other dolphins visually was chosen for the task. When his trainer gives a hand signal, Tanner knows to copy the moves of the dolphin next to him. To see how he performed without sight, his eyes were covered with plastic eye cups after he was given the cue. Then a second dolphin performed an action, or produced a sound Tanner was familiar with, and the researchers observed his ability to replicate it. Unsurprisingly, the team found that he had no problem reproducing sounds blindfolded. But he also reproduced a lot of actions with his eyes covered up, and even when he made mistakes the move wasn't too far off. "Since we know he wasn't using sight, he had to be using sound," says Kelly Jaakkola, a member of the team. "Either by recognising the characteristic sound that the behaviour makes, like you or I may recognise the sound of hands clapping, or by using echolocation." © Copyright Reed Business Information Ltd.

Tired bees make poor dancers

Joseph Milton We all struggle to communicate after a sleepless night, let alone pull off our best dance moves, and it seems that honeybees are no different. Sleep-deprived bees are less proficient than their well-rested hive mates at indicating the location of a food source to other members of the colony by waggle dancing — the figure-of-eight dance used to communicate the quality and location of nectar supplies to the hive — according to a study published online this week in the Proceedings of the National Academy of Sciences1. Like all animals, European honeybees (Apis mellifera) rely on a sleep-like state of inactivity to survive — but sleep in insects and the effects of sleep deprivation on their behaviour are poorly understood. Barrett Klein, who led the study as a graduate student at the University of Texas at Austin, says that sleep deprivation could conceivably affect bees when hives are invaded by predators or parasites, when apiculturists transport colonies over long distances, or as an everyday consequence of the busy nature of hives. "Bees bustle around, frequently bumping into each other," he says. "It's also possible that sleep deprivation could exacerbate colony collapse disorder," he adds, referring to recent alarming declines in bee populations worldwide, "although this hasn't been tested." © 2010 Nature Publishing Group,

Related chapters from BN: Chapter 14: Biological Rhythms, Sleep, and Dreaming; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 10: Biological Rhythms and Sleep; Chapter 15: Language and Lateralization
Link ID: 14778 - Posted: 12.14.2010

Sleepy bees slur their waggle dance moves

by Jessica Hamzelou No one works well when tired, and insects are no exception. Just like us, sleepy bees make shoddy dancers and poor communicators. Forager honeybees (Apis mellifera), like humans, normally get around eight hours of sleep a night. To find out whether a good night's sleep is important for the bees' communicative waggle dance, Barrett Klein at the University of Texas in Austin and his colleagues kept half of a group of 50 bees awake overnight. To do this, Klein stuck a small piece of either steel or non-magnetic copper onto each of the bees. During the night, from dusk until dawn, he passed a magnet back and forth over the hive, jostling and waking the 25 bees with a steel spot three times a minute. When the team watched videos of the bees filmed the following day, they found that the sleep-deprived bees performed less precise waggle dances. The tired insects had more variation in the angle of their dances, and as a result gave other bees poor directions to a food source. Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1009439108 © Copyright Reed Business Information Ltd.

Killer Whales Mimic Friends and Foes

by Jane J. Lee Just as human cliques have their own language quirks, groups of killer whales have their own dialects. But that doesn't stop them from imitating one another. A new study of wild orcas shows that they mimic calls from other groups even when members of that group aren't around. The whales could have multiple uses for the imitation, such as labeling outsiders or keeping tabs on their location. Vocal mimicry in nonhuman mammals is rare. Songbirds are famous for imitating their neighbors, an ability they use to defend their territories. Anecdotal reports suggest that orcas mimic, too, which makes sense considering scientists have shown that their close cousins, bottlenose dolphins, mimic one another in captivity. But studying these animals in the wild is challenging because current technology can't pinpoint which animal is doing the calling, especially during mingling sessions when they are close together. While analyzing how wild orcas near Vancouver Island in British Columbia, Canada, used sound when socializing, behavioral biologist Brigitte Weiß of the University of Vienna discovered a set of calls that were not a part of their normal repertoires. The calls seemed to resemble the calls of foreign groups that the original group would have mingled with to mate or cement alliances. Weiß and colleagues then categorized the calls and produced sonograms, which show the structure of the sound waves, to compare against sonograms of the originals. The study, published online 15 July in Marine Mammal Science, concludes that resident orcas mimicked the calls of foreign groups about once every 500 calls. © 2010 American Association for the Advancement of Science

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 14738 - Posted: 12.04.2010

Waking in the Clouds to a Chorus of Birds

By CHRIS FILARDI Waking at 1,600 meters in the Solomons is like waking in the clouds. Cloud days begin with a vigil of sorts: a slow and deliberate ascent up a ladderlike trail through the tangles to a perch that hangs out into the gloaming heart of morning cloud surrounding the high ridges. At dawn, wind heaves up from the central caldera, shifting the heavy mist. Other than this mountain breath, there is little indication of anything beyond moss, wood and orchids splaying out everywhere along the limb holding me up. From this perch one can read the morning chorus of birdsong. Many bird species roost for the night at perches reflecting their distribution within a forest and then sing in a beautifully clocklike species-specific cadence at dawn. This awakening can disclose the presence and distribution of species that are otherwise seldom detected and, properly interpreted, can provide an incredible amount of information about a forest bird community. Mornings here I actually hear two choruses — one softly twittering in the mossy heights, and another, almost a din, rising from the crater floor far below. It is remarkable, indescribable really, hearing montane songs in the leafy tufts around my head unique to Kolombangara and reminiscent of Eurasia or North America, and simultaneously the blare of whistlers, monarch flycatchers, coucals, fantails and cuckoo-shrikes rising from tall hill forest nearly 1,100 meters below. Copyright 2010 The New York Times Company

Related chapters from BN: Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 14570 - Posted: 10.19.2010

Dolphin species attempt 'common language'

By Matt Walker When two dolphin species come together, they attempt to find a common language, preliminary research suggests. Bottlenose and Guyana dolphins, two distantly related species, often come together to socialise in waters off the coast of Costa Rica. Both species make unique sounds, but when they gather, they change the way they communicate, and begin using an intermediate language. That raises the possibility the two species are communicating in some way. Details are published in the journal Ethology. It is not yet clear exactly what is taking place between the two dolphin species, but it is the first evidence that the animals modify their communications in the presence of other species, not just other dolphins of their own kind. Biologist Dr Laura May-Collado of the University of Puerto Rico in San Juan made the discovery studying dolphins swimming in the Gandoca-Manzanillo Wildlife Refuge of the southern Caribbean coast of Costa Rica. Bottlenose dolphins (Tursiops truncatus) are larger, measuring up to 3.8m long, with a long dorsal fin. Guyana dolphins (Sotalia guianensis) are much smaller, measuring 2.1m long, and have a smaller dorsal fin and longer snout, known as a rostrum. BBC © MMX

Reports From the Hive, Where the Swarm Concurs

By KATHERINE BOUTON What can we learn from the bees? Honeybees practice a kind of consensus democracy similar to what happens at a New England town meeting, says Thomas D. Seeley, author of “Honeybee Democracy.” A group comes to a decision through a consideration of options and a process of elimination. The bees are making a life-and-death decision: where to establish a new hive. Choosing a site that is too exposed, too small or too close to the ground can be fatal. Swarms don’t always do it right, but they do succeed a remarkable amount of the time, with 10,000 or more bees following the advice and signals of a few hundred leaders to re-establish themselves in a new location every spring. Along the way they have to make sure the precious queen, fatter and more sluggish than the others and prone to take a rest stop, is not lost. Dr. Seeley, professor and chairman in the department of neurobiology and behavior at Cornell University, makes a good-faith case for the effectiveness of bee-management style as applied to humans, but I couldn’t help suspecting that it might have been at the urging of his publisher. Bees and ants are the management model of choice just now, and books like “The Smart Swarm,” by Peter Miller, a senior editor at National Geographic, are quite admired in the business world. But as Dr. Seeley himself acknowledges, consensus democracy requires a like-minded electorate, and how often do we get that in real life? Copyright 2010 The New York Times Company

Fish Talk to One Another

The undersea world isn't as quiet as we thought, according to a New Zealand researcher who found fish can "talk" to each other. Fish communicate with noises including grunts, chirps and pops, University of Auckland marine scientist Shahriman Ghazali has discovered according to newspaper reports Wednesday. "All fish can hear, but not all can make sound -- pops and other sounds made by vibrating their swim bladder, a muscle they can contract," Ghazali told the New Zealand Herald. Fish are believed to communicate with each other for different reasons, including attracting mates, scaring off predators or orienting themselves. The gurnard species has a wide vocal repertoire and keeps up a constant chatter, Ghazali found after studying different species of fish placed into tanks. On the other hand, cod usually kept silent, except when they were spawning. "The hypothesis is that they are using sound as a synchronization so that the male and female release their eggs at the same time for fertilization," he said. Some reef fish, such as the damselfish, made sounds to attempt to scare off threatening fish and even divers, he said. But anyone hoping to strike up a conversation with their pet goldfish is out of luck. © 2010 Discovery Communications, LLC.

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: 14238 - Posted: 07.08.2010

Whales’ Lower-Pitch Sound Has Experts Guessing

By BINA VENKATARAMAN The song of the blue whale, one of the eeriest sounds in the ocean, has mysteriously grown deeper. The calls have been steadily dropping in frequency for seven populations of blue whales around the world over the past 40 years, say researchers at the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration and WhaleAcoustics, a private research company. The scientists analyzed data collected with hydrophones and other tools and found that the songs, which they believe are by males advertising for mates, had lowered by as much as 30 percent in certain populations. Much of the song lies at frequencies too low to be detected by the human ear. The study, though not yet published, has been reviewed by several experts in the field who, in interviews, called the global decline “dramatic,” “significant,” “convincing” and “unequivocal.” Scientists cannot explain why blue whales from places as disparate as the northern Pacific and the Southern Ocean, which surrounds Antarctica, would drop the pitch of their songs. Each blue whale population has a distinct tempo and tone set to its vocals. John Hildebrand, professor of oceanography at Scripps and an author of the study, said the drop might signal a rebound in the population of blue whales since commercial whaling bans began to take effect in the 1970s. Copyright 2008 The New York Times Company

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: 11881 - Posted: 06.24.2010

World’s largest forest birds may produce world's deepest bird calls

Cassowaries’ low-frequency sounds may give insight into dinosaur communications NEW YORK -- A family of huge forest birds living in the dense jungles of Papua New Guinea emit low-frequency calls deeper than virtually all other bird species, possibly to communicate through thick forest foliage, according to a study published by the New York-based Wildlife Conservation Society. Published in the recent issue of the scientific journal The Auk, the study says that three species of cassowaries – flightless birds that can weigh as much as 125 pounds – produce a "booming" call so low that humans may not be able to detect much of the sound. The researchers draw similarities between the birds' calls and the rumbling elephants make to communicate. "When close to the bird, these calls can be heard or felt as an unsettling sensation, similar to how observers describe elephant vocalizations," said WCS researcher Dr. Andrew Mack, the lead author of the study.

Grrr� what's 'Step away from the bone' in dog?

by Ewen Callaway The canine phrase book has collected its first entries. Dogs understand the meaning of different growls, from a rumble that says "back off" to playful snarls made in a tug-of-war game. Proving that animal vocalisations have specific meanings – and what they could be – is challenging. In 2008, P�ter Pongr�cz, a behavioural biologist at Eötvös Lorand University in Budapest, Hungary, monitored dogs' heart rates to show that they seem to notice a difference between barks aimed at strangers and those directed at nothing in particular. Now he has gone a step further and shown that dogs respond differently to different vocalisations. Pongr�cz's team recorded growls from 20 pet dogs in three different situations: a tug-of-war game with their owner, competing with another dog for a bone and growling at an approaching stranger. Growls may convey more meaning than barks, says Pongr�cz: wolves rarely bark, and he says dogs may have learned to bark to get human attention. The team played the recordings to 36 other dogs that had each been left to gnaw on a bone. Only those that heard the food-guarding growls tended to back off from the bone and stay away. "It seems dogs can understand something about the context," Pongr�cz says. Back to the bone © Copyright Reed Business Information Ltd

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