Links for Keyword: Animal Communication

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How People Learned To Recognize Monkey Calls Reveals How We All Make Sense Of Sound

Jon Hamilton The words "dog" and "fog" sound pretty similar. Yet even a preschooler knows whether you're talking about a puppy or the weather. Now scientists at Georgetown University Medical Center in Washington, D.C., have identified a two-step process that helps our brains learn to first recognize, then categorize new sounds even when the differences are subtle. And it turns out the process is very similar to the way the human brain categorizes visual information, the Georgetown team reports Wednesday in the journal Neuron. "That's very exciting because it suggests there are general principles at work here of how the brain makes sense of the world," says Maximilian Riesenhuber, an author of the study and a professor in Georgetown University School of Medicine's Department of Neuroscience. The finding also could help explain what goes wrong in disorders like dyslexia, which can impair the brain's ability to make sense of what it sees and hears, Riesenhuber says. The research began as an effort to understand how the brain is able to accomplish feats like recognizing a familiar word, even when it's spoken with an accent or unusual pronunciation. "You hear my voice," says Riesenhuber, who has a slight German accent. "You've probably never heard me before. But you can hopefully recognize what I'm saying." © 2018 npr

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: 24882 - Posted: 04.19.2018

Bowhead whales: jazz artists of the deep whose calls rival birdsong

Agence France-Presse How do bowhead whales in the unbroken darkness of the Arctic’s polar winter keep busy during breeding season? They sing, of course. From late autumn to early spring, off the east coast of Greenland, some 200 bowheads, hunted to the edge of extinction, serenade each other with compositions from a vast repertoire of song, according to a study published on Wednesday. “It was astonishing,” said the lead author, Kate Stafford, an oceanographer at the University of Washington’s Applied Physics Laboratory in Seattle, who eavesdropped on these subaquatic concerts. “Bowhead whales were singing loudly, from November until April” – non-stop, 24/7 – “and they were singing many, many different songs.” Stafford and three colleagues counted 184 distinct melodies over a three-year period, which may make bowheads one of the most prolific composers in the animal kingdom. “The diversity and inter-annual variability in songs of bowhead whales in this study are rivalled only by a few species of songbirds,” the study found. Unlike mating calls, songs are complex musical phrases that are not genetically hard-wired but must be learned. Only a handful of mammals – some bats and a family of apes called gibbons, for example – vocalise in ways akin to bird song, and when they do it is quite repetitive. The only other whale that produces elaborate songs is the humpback, which has been extensively studied in its breeding grounds near Hawaii and off the coast of Mexico. The humpback’s melody is shared among a given population over a period of a year, and gives way to a new tune each spring. Bowhead whales, it turns out, are far more versatile and would appear to improvise new songs all the time. © 2018 Guardian News and Media Limited

Related chapters from BN: Chapter 19: Language and Lateralization; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 15: Language and Lateralization; Chapter 8: Hormones and Sex
Link ID: 24819 - Posted: 04.04.2018

Near Noisy Oil Fields, Lovesick Birds Change Their Tunes

By Hiroko Tabuchi If a sparrow sings his heart out on an oil field, but his would-be sweetheart can’t hear him above the oil pumps, what’s a bird to do? In Alberta, Canada, researchers analyzed hundreds of hours of Savannah sparrow love songs and discovered something extraordinary: To be heard above the din, the birds are changing their tune in complex ways that scientists are only starting to understand. “They’re tailoring their songs depending on which part of their message is the most affected,” said Miyako Warrington, a University of Manitoba biologist who led a recent study on how sparrows cope with noise from the oil and gas infrastructure that dots Canada’s landscape. “This seems to show a complex level of adaptation. It’s not just everybody talking louder.” Dr. Warrington is one of a growing number of scholars who study the noise generated by human activity — drills, turbines, roaring jet engines — and how that affects the natural world around us. Mining on the fringes of the Brazilian rain forest, for instance, is disrupting the calls of local black-fronted titi monkeys, a study found last year. Whales and dolphins are known to be particularly vulnerable to the groans of ship engines or offshore drilling, which can disrupt the complex ways they communicate. Research has shown that noise pollution has doubled the background sound levels in more than 60 percent of protected areas in the United States. And humans are not immune to the din. Epidemiologists have linked traffic noise to cardiovascular and other diseases. © 2018 The New York Times Company

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 15: Language and Lateralization
Link ID: 24758 - Posted: 03.15.2018

Female birds sing. These biologists want you to listen.

by Ben Guarino Only male birds sing. For years that was the assumption among amateur birdwatchers and ornithologists alike. After all, male birds are “the obvious ones,” says Lauryn Benedict, a biologist at the University of Northern Colorado. “They're out there showing off, strutting their stuff.” But Benedict and fellow birdsong expert Karan Odom, a biologist at Cornell University, want you to look closer if you hear a chirp or warble. Female birds are not, on the whole, silent. In a call-to-ears published Wednesday in the journal the Auk, the two scientists say that “birders and researchers need to be aware that female birds regularly sing, and they need to take the time to evaluate the sex of singing birds.” The tipping point for Odom came in 2014, when she concluded that birdsong is an ancestral trait shared by both sexes. Female birds sang in 71 percent of 323 species surveyed, she and her colleagues reported then in a Nature Communications paper. They traced this behavior through the bird family tree, winding back the generations to a common singing ancestor. At that point in history, they wrote, both male and female birds sang. Benedict, who was not involved with that work, described it like this: Instead of males evolving to be loud, “females have evolved to be quiet.” © 1996-2018 The Washington Post

Chimpanzees, bonobos, and even humans may share ancient body language

By Virginia Morell Want to say “Hello,” but don’t know the local language? Try waving your hand. Such gestures, common among humans, are also surprisingly similar among chimpanzees and bonobos, our closest great ape relatives. Now, a new study has identified numerous gestures that mean the same thing to both species. That suggests these signals have biological underpinnings and could be inherited from our last common ancestor. Gestures, signals often used to get someone’s attention or ask for or stop something, are not technically languages. They don’t have specific linguistic and grammatical rules or accepted vocabularies. But gestures still have meaning: Among chimpanzees, for example, scientists have documented that many of their movements—from mouth stroking to request food or arm raising to request grooming—are used to elicit specific responses from other chimpanzees. Researchers have now found something similar in bonobos, great apes closely related to chimpanzees but with longer legs, pink lips, and long hair that’s parted in the middle on their heads. Scientists started by shooting and analyzing videos of wild bonobos in the Democratic Republic of the Congo. When a bonobo made a common gesture that brought a consistent, satisfying response from others, it was added to the list. For example, when one bonobo looked at another while loudly scratching one arm, the second often responded by grooming the first. Because the first bonobo was almost always satisfied by this response, the researchers concluded that a “big, loud scratch” is a request for grooming. The scientists next compared the bonobo gestures to those of chimpanzees, and found that their repertoires overlapped by about 90%, significantly more than “would be expected by chance,” says lead author Kirsty Graham, a comparative psychologist at the University of York in the United Kingdom. © 2018 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: 24709 - Posted: 02.28.2018

Keeping A Close Eye: Dogs, Social Referencing, And Evolution

Barbara J. King When humans talk to each other or walk alongside each other, we tend to match each other's subtle movements. Called interpersonal movement synchrony in the science literature and mirroring in the popular media, it's an often-unconscious process during which we match our gestures and pace to that of our social partner of the moment. Writing in the March issue of the journal Animal Cognition, Charlotte Duranton, Thierry Bedossa, and Florence Gaunet note that this process is "evolutionarily adaptive" for us: "It contributes to communication between individuals by signaling the convergence of their inner states and fostering social cohesion." Then, these three researchers present evidence to show that dogs synchronize their walking pace with their humans in a way that may also reflect an evolutionary adaptation. In an experiment, 36 pet dogs were brought to an open area in Maisons-Laffitte, France, with their owners. After a 15-minute free period, the owner-dog pairs experienced three testing conditions presented in random order. These were: stay-still (owner didn't move for 10 seconds), normal-walk (owners walked at normal speed for 10 seconds), and fast-walk (owner walked fast for 10 seconds). Importantly, the dogs were off-leash and, thus, not tethered in any way to the speed of the owners. The owners were told not to look at, or talk to, their dogs — or to show any evident emotion. The experimenters filmed the trials as they occurred. The dogs synchronized their pace closely with their owners, speeding up when the owners walked at an unnaturally fast pace. (The dogs in their regular routines were used to walking at a normal pace, with the owners often pausing to chat with other people). © 2018 npr

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: 24692 - Posted: 02.23.2018

War Dance of the Honeybee

By Karl Gruber A. Fujiwara et al., “First report on the emergency dance of Apis cerana japonica, which induces odorous plant material collection in response to Vespa mandarinia japonica scouting,” Entomol Sci, doi:10.1111/ens.12285, 2017. The Waggle Dance Honeybees are famous for their waggle dances—figure-eight boogies that foragers use to inform nestmates about the locations of food or water. But entomologists were unclear about whether the dances could also be used to help ensure colony safety. Unwelcome Guests Ayumi Fujiwara, a graduate student at the University of Tokyo, and colleagues simulated wasp attacks on hives of the Japanese honeybee (Apis cerana japonica) to test the bees’ response to danger. “Giant wasps attack the nests of honeybees to feed their brood in autumn. As a result, wasps may sometimes annihilate a whole honeybee colony,” she says. Dance Off The researchers found that the bees did use a waggle dance as a warning signal, but only in response to sightings of one wasp species, Vespa mandarinia japonica. “The hive entrance dance informs bees’ nestmates of a specific emergency and of the urgent necessity to collect odorous plant materials as a counterattack strategy,” Fujiwara says. The bees collect stinky plant materials, such as leaves from Nepalese smartweed (Persicaria nepalensis), and smear them at the hive entrance to deter the wasps. Decoding the Moves The information coded in this new waggle dance is not yet completely clear, notes Margaret Couvillon, a biologist and honeybee specialist at Virginia Tech. “What would be interesting to see is if there are any differences in the conveying of directional information in this defensive context versus the regular foraging context,” she says. “Nature tends to be parsimonious in finding solutions, so we might expect that the bees use a similar mechanism in these different situations.” © 1986-2018 The Scientist

A killer whale gives a raspberry and says ‘hello’

Susan Milius Ready for sketch comedy she’s not. But a 14-year-old killer whale named Wikie has shown promise in mimicking strange sounds, such as a human “hello” — plus some rude noises. Scientists recorded Wikie at her home in Marineland Aquarium in Antibes, France, imitating another killer whale’s loud “raspberry” sounds, as well as a trumpeting elephant and humans saying such words as “one, two, three.” The orca’s efforts were overall “recognizable” as attempted copies, comparative psychologist José Zamorano Abramson of Complutense University of Madrid and colleagues report January 31 in Proceedings of the Royal Society B. Just how close Wikie’s imitations come to the originals depends on whether you’re emphasizing the rhythm or other aspects of sound, Abramson says. Six people judged Wikie’s mimicry ability, and a computer program also rated her skills. She did better at some sounds, like blowing raspberries and saying “hello-hello,” than others, including saying “bye-bye.” Imitating human speech is especially challenging for killer whales. Instead of vocalizing by passing air through their throats, they sound off by forcing air through passageways in the upper parts of their heads. It’s “like speaking with the nose,” Abramson says. The research supports the idea that imitation plays a role in how killer whales develop their elaborate dialects of bleating pulses. Cetaceans are rare among mammals in that, like humans, they learn how to make the sounds their species uses to communicate. © Society for Science & the Public 2000 - 2017

Fowl Language: AI Decodes the Nuances of Chicken “Speech”

By Ferris Jabr Chickens are loquacious creatures, and Kevin Mitchell would know. He oversees the care of about a million of them on Wilcox Farms properties in Washington State and Oregon. Mitchell says the birds have “patterns of speech” that reveal a lot about their well-being. They are usually noisiest in the morning—a robust concert of clucks, chortles and caws. “When I hear that, I know they are pretty healthy and happy,” Mitchell says. In the evenings when they’re preparing to roost, the chickens are much more mellow, cooing softly. When a hen lays an egg she celebrates with a series of staccato clucks, like drumbeats, culminating in a loud “buck-caw!” If chickens detect an aerial predator—say, by spotting the shadow of a hawk or eagle—they produce a short, high-pitched shriek. And they have a distinct warning for terrestrial threats: The repetitive clucking most people associate with chickens is in fact a ground predator alarm call. One morning many years ago Mitchell entered a chicken house and found it oddly calm and quiet. Instead of making the usual ruckus, the birds were murmuring and shuffling lethargically. He soon discovered that an automated lighting system had failed and the lights had not switched off the night before; the chickens were sleep-deprived. If he had only been able to eavesdrop on the flock, he might have known much sooner that something was amiss. Over the past five years, engineers and poultry scientists at The University of Georgia and Georgia Institute of Technology have been collaborating to help farmers like Mitchell make better use of the information latent in chicken chatter. © 2017 Scientific American

How baby bats develop their dialects

Rachael Lallensack It takes a village to teach a bat how to communicate. Baby Egyptian fruit bats learn calls from their mothers, but research now shows that they can learn new dialects, or the pitch of their vocalizations, from the colony members around them. Learning to communicate by repeating the noises that others make is something only a few mammal groups — including humans, whales and dolphins — are known to do. Researchers call this vocal learning, and it's something that they're starting to study in bats. Findings published on 31 October in PLOS Biology1 show that bats can also pick things up from the group around them, a process that the authors dub crowd vocal learning. Bats are becoming the best organism to use in studies of how mammals learn to vocalize, because they’re more easily manipulated in the lab than whales or dolphins. The latest research underscores their importance, says neuroscientist Michael Yartsev of the University of California, Berkeley, who was not involved with the work. Egyptian fruit bats (Rousettus aegyptiacus) are highly social and live in colonies with dozens to thousands of other bats. To see how the pups learn dialects, researchers caught 15 pregnant Egyptian fruit bats and took them into the lab. To control for potential genetic effects, they ensured that the mothers weren't closely related. The team then split the mothers into three groups of five and put each group into one of three chambers, where the mothers gave birth to their young. The scientists used recordings of wild Egyptian fruit bat colonies that were low in frequency, high or a mix of both frequencies, and then piped one pitch into each chamber. © 2017 Macmillan Publishers Limited,

The Click Effect

By SANDY SMOLAN I’ve long been interested in the capacity of storytelling and journalism to transport an audience. Shooting my first documentary in North Africa 35 years ago, I used multiple projectors and screens to create an immersive experience. The approach at the time was experimental and while I moved on to more traditional storytelling in features, television and documentaries, I always held on to the idea of using immersive environments to transport viewers and allow them to experience an expanded vision of the world. They surrounded the divers and started clicking — they seemed to be saying hello. Then last year I visited the virtual reality lab at Stanford, which is at the fore of contemporary immersive journalism. I realized that V.R. had the potential to become a powerful new form of storytelling, and the medium has been evolving faster than anyone had ever expected. After I read James Nestor’s book “Deep,” about free diving and the human connection to the ocean, I realized that the combination of stunning imagery and the way in which a team of researchers were studying the language of whales and dolphins by free diving with them would translate perfectly to V.R. I had never forgotten my first open water dive in the Caribbean with my father when I was 17 and the transcendent experience of being suspended 30 feet beneath the surface, midway between the boat above us and the white sand of the ocean floor below. Now my son has become a free diver and as I recently watched him dive silently, on a single breath, his body elongated with outsize fins, unencumbered by tanks, regulators and the noise of escaping bubbles, I saw what James so eloquently described in his book — a human being interacting with the ocean and marine life in a manner few people can ever experience. © 2017 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: 24032 - Posted: 09.04.2017

Yes, We Can Communicate with Animals

By Denise D. Cummins Looking directly at the camera, NPR's Skunk Bear host Adam Cole laments, "It's pretty clear that I'll never be able to have a real human-style conversation with an ape.” In his short and very entertaining video, Cole summarizes decades of research aimed at teaching apes human language, all of which, we are to understand, came to naught. But what the video actually shows us is how little the average person (and many scientists) understands about language. At one point, Cole tells his dog to sit, and the dog sits. This, he tells us, is not evidence that the dog knows English. But actually, it is. The dog's behavior shows us that he is capable of understanding the simple concept of sitting, that he is capable of distinguishing the verbal signal "sit" from other verbal signals, and that he is capable of connecting the two. This isn't rocket science, it isn't magic, and it isn't anthropomorphizing. It is just the way word learning works. In studies conducted at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, a border collie named Rico was taught the meanings of 200 words. He could even use theprocess of elimination to figure out unfamiliar words: If he already knew the word "ball,” and his trainer showed him a ball and a stick and told him to get the "stick,” he would bring the stick. He could remember new words even after a month of not hearing them. © 2017 Scientific American,

These highly social birds can make ‘sentences,’ just like humans

By Giorgia Guglielmi Tits amazing are birds Japanese. If you didn’t get that, you wouldn’t be alone: Humans figure out the meaning of sentences like this using grammatical rules such as word order. It turns out that Japanese tits, social birds that live in Japan and the Russian Far East, do it too. These wild birds respond to calls they’ve never heard before only if the chirps are in the right order, researchers report today in Current Biology. When a predator threatens the flock, Japanese tits produce something called a “mobbing call,” with the sequence ABC-D. By itself, the ABC part of the call means “danger.” But the D part of the call—similar to the “recruitment call” of a close relative, the willow tit—attracts flock members when there’s something to share, such as food. When the two parts are produced together, Japanese tits flock together to mob the intruder. To find out if the order of the calls mattered, researchers created a song that Japanese tits had never heard before—an artificial sequence made up of the Japanese tit’s ABC alert, followed by the willow tit’s recruitment call, tӓӓ. (You can listen to them, above.) They then played it from a loudspeaker for a flock of nearby tits. When Japanese tits heard the ABC- tӓӓ call, they turned their heads, looking for a predator, as they approached the loudspeaker. But when the artificial sequence was reversed (tӓӓ-ABC), the birds didn’t react. © 2017 American Association for the Advancement of Science.

Can you tell whether this frog is excited just by listening to its voice?

By Virginia Morell Frogs, birds, monkeys, and humans make a variety of sounds expressing emotions. And because that ability is shared by every land-dwelling animal with a backbone, Charles Darwin argued that these cries have a common origin. Humans can recognize the emotions in the voices of other mammals, including cats and dogs. To find out whether we can also do this for nonmammals, scientists gathered recordings from nine species, including the hourglass tree frog (above), American alligator, common raven, Barbary macaque, and Tamil-speaking humans in two emotional states: highly and mildly aroused. They played the calls to 75 people—men and women who spoke English, German, or Mandarin—and asked them to judge whether the animal was very excited or subdued. You can try it yourself below: Participants easily passed the tests. Some 90% of listeners distinguished between the excited and calmer sounds of the tree frogs (which were calling for mates), and 87% scored the alligator calls correctly. Sixty-two percent were right about the ravens’ calls of alarm. © 2017 American Association for the Advancement of Science.

Elephant seals recognize rivals by the tempo of their calls

by Laurel Hamers The tempo of a male elephant seal’s call broadcasts his identity to rival males, a new study finds. Every male elephant seal has a distinct vocalization that sounds something like a sputtering lawnmower — pulses of sound in a pattern and at a pace that stays the same over time. At a California state park where elephant seals breed each year, researchers played different variations of an alpha male’s threat call to subordinate males who knew him. The seals weren’t as responsive when the tempo of that call was modified substantially, suggesting they didn’t recognize it as a threat. Modifying the call’s timbre — the acoustic quality of the sound — had the same effect, researchers report August 7 in Current Biology. Unlike dolphins and songbirds, elephant seals don’t seem to vary pitch to communicate. Those vocal name tags serve a purpose. During breeding season, male elephant seals spend three months on land without food or water, competing with rivals for social status and mating rights. Fights between two blubbery car-sized animals can be brutal. “We’ve seen males lose their noses,” says Caroline Casey, a biologist at the University of California, Santa Cruz. For lower-ranking males, identifying an alpha male by his call and then backing off might prevent a beach brawl. |© Society for Science & the Public 2000 - 2017

Related chapters from BN: Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases; Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 23859 - Posted: 07.21.2017

Drumming Cockatoos and the Rhythms of Love

By STEPH YIN Whales and songbirds produce sounds resembling human music, and chimpanzees and crows use tools. But only one nonhuman animal is known to marry these two skills. Palm cockatoos from northern Australia modify sticks and pods and use them to drum regular rhythms, according to new research published in Science Advances on Wednesday. In most cases, males drop beats in the presence of females, suggesting they perform the skill to show off to mates. The birds even have their own signature cadences, not unlike human musicians. This example is “the closest we have so far to musical instrument use and rhythm in humans,” said Robert Heinsohn, a professor of evolutionary and conservation biology at the Australian National University and an author of the paper. A palm cockatoo drumming performance starts with instrument fashioning — an opportunity to show off beak strength and cleverness (the birds are incredibly intelligent). Often, as a female is watching, a male will ostentatiously break a hefty stick off a tree and trim it to about the length of a pencil. Holding the stick, or occasionally a hard seedpod, with his left foot (parrots are typically left-footed), the male taps a beat on his tree perch. Occasionally he mixes in a whistle or other sounds from an impressive repertoire of around 20 syllables. As he grows more aroused, the crest feathers on his head become erect. Spreading his wings, he pirouettes and bobs his head deeply, like an expressive pianist. He uncovers his red cheek patches — the only swaths of color on his otherwise black body — and they fill with blood, brightening like a blush. Over seven years, Dr. Heinsohn and his collaborators collected audio and video recordings of 18 male palm cockatoos exhibiting such behaviors in Australia’s Cape York Peninsula, where the birds are considered vulnerable because of aluminum ore mining. © 2017 The New York Times Company

Related chapters from BN: Chapter 9: Hearing, Balance, Taste, and Smell; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 8: Hormones and Sex
Link ID: 23790 - Posted: 06.29.2017

When Dogs Hear a Growl, They Know What to Do

By Julie Hecht I have been scaring dog lovers for nearly a decade, and Tamas Farago—lead researcher behind a new study on dog growls and cross-species communication—is mostly to blame. I met Farago in 2010 when visiting his research group—the Family Dog Project at Eotvos Lorand University—to conduct my Masters research. By then, Farago was already immersed in the study of dog vocalizations—particularly their barks and growls—so when my study concluded and it was time to leave Budapest, I departed with not only a deep appreciation for paprika and palinka, but also a few audio clips of dogs growling, courtesy of Farago. Since then, whenever I give a talk about canine science, audience members are sure to chuckle, their faces brightening, as recordings of a dog’s breathy, garbled, fast-paced, play growls take over the room. But when I play the low, elongated aggressive growls corresponding to a dog being approached by a threatening stranger or a dog guarding food, even my hair will often stand up. These growls mean business. If a dog happens to be attending the talk—not that I hold lectures for dogs, but if a human brought their dog—I take note before playing the growls. This is because a 2010 study by Farago and colleagues found that dogs not only listen to growls, but extract meaningful information from them. Here’s how they figured this out: In the study, dogs entered a room where they came across a bone. Fine. Normal so far. Just a bone sitting all alone. But unbeknownst to the dogs, a speaker was concealed in a covered crate sitting just behind the bone, and as the dogs approached, one of three growls was played from the speaker (food guarding, threatening stranger, or play). Excellent work sneaky researchers! © 2017 Scientific American

Barking up the right tree: study shows we can understand dog growls

Nicola Davis Humans can determine a dog’s mood by the sound of its growl, scientists have found, with women showing greater ability than men. While previous studies have found that humans can unpick the context of barks, the latest study investigated whether the same was true of canine grumbles, with some previous research suggesting humans struggle to differentiate between playful and aggressive vocalisations. “It is an important thing that humans are capable [of recognising] the emotional state of another species just based on the vocal characteristics,” said Tamás Faragó, first author of the study from Eötvös Loránd University in Hungary. To tackle the conundrum, Faragó and colleagues used previously captured recordings of 18 dogs growling in three contexts: guarding food from other dogs, playing tug-of-war with humans, and being threatened by the approach of a stranger. The researchers monitored several features, including the length of each growl and its frequency. Two sets of the recordings, which included two growls from each context, were played to 40 adults. Each participant was asked to record their impression of the first set of growls on a sliding scale, rating their perception of the dog for five emotions: fear, aggression, despair, happiness and playfulness. © 2017 Guardian News and Media Limited

Humpback calves ‘whisper’ to avoid being heard by killer whales

By Virginia Morell Humpback whales are known for their operatic songs that carry across the seas. Their calves, however, whisper, uttering soft squeaks and grunts to their mothers (which you can hear above). Now, a new study suggests that loud calf voices can also attract some unwanted visitors: male humpbacks, who might separate the pair by trying to mate with the mother, and killer whales, who dine on young humpbacks. To record their sounds, scientists placed temporary tagging devices on eight humpback whale mothers and calves in the Exmouth Gulf off Western Australia, where the young whales spend months suckling to gain enough weight for their annual migrations to the Antarctic or Arctic. After listening to the recordings, scientists say the calves’ careful whispers are not cries for food, as previously thought. Instead, they may help them stay in close contact with their mothers when swimming. And, say researchers, writing today in Functional Ecology, the low decibel sounds help keep would-be predators away from the “nursery.” © 2017 American Association for the Advancement of Science

Birds May Make Music, But They Lack Rhythm

By Jenny Rood To human ears, the trilling of birdsong ranks among nature’s most musical sounds. That similarity to human music is now inspiring researchers to apply music theory to avian vocalizations. For example, zebra finch neurobiologist Ofer Tchernichovski of the City University of New York, together with musician and musicologist Hollis Taylor, recently analyzed the song of the Australian pied butcherbird (Cracticus nigrogularis) and found an inverse relationship between motif complexity and repetition that paralleled patterns found in human music (R Soc Open Sci, 3:160357, 2016). Tchernichovski’s work also suggests that birds can perceive rhythm and change their calls in response. Last year, he and colleague Eitan Globerson, a symphony conductor at the Jerusalem Academy of Music and Dance as well as a neurobiologist at Bar Ilan University in Israel, demonstrated that zebra finches, a vocal learning species, adapt their innate calls—as opposed to learned song—to avoid overlapping with unusual rhythmic patterns produced by a vocal robot (Curr Biol, 26:309-18, 2016). The researchers also found that both males and females use the brain’s song system to do this, although females do not learn song. But these complexities of birdsong might be more comparable to human speech than to human music, says Henkjan Honing, a music cognition scientist at the University of Amsterdam. Honing’s research suggests that some birds don’t discern rhythm well. Zebra finches, for example, seem to pay attention to pauses between notes on short time scales but have trouble recognizing overarching rhythmic patterns—one of the key skills thought necessary for musical perception (Front Psychol, doi:10.3389/fpsyg.2016.00730, 2016). © 1986-2017 The Scientist

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