3144. The Significance of Whale Songs

By Karen Weintraub, The New York Times, January 7, 2019


A juvenile male humpback whale in waters off Sri Lanka. The males may be singing certain tunes to attract mates, although scientists listening to the songs suspect there may also be other reasons for the music shared among these giants, even when they are miles and miles apart.CreditCreditTony Wu/Minden Pictures

Sometimes a whale just wants to change its tune.

That’s one of the things researchers have learned recently by eavesdropping on whales in several parts of the world and listening for changes in their pattern and pitch. Together, the new studies suggest that whales are not just whistling in the water, but constantly evolving a form of communication that we are only beginning to understand.

Most whales and dolphins vocalize, but dolphins and toothed whales mostly make clicking and whistling sounds. Humpbacks, and possiblybowheads, sing complex songs with repeated patterns, said Michael Noad, an associate professor in the Cetacean Ecology and Acoustics Laboratory at the University of Queensland in Australia.

Birds may broadcast their social hierarchy among song-sharing populations by allowing the dominant bird to pick the playlist and patterns. But how and why whales pass song fragments across hundreds of miles, and to thousands of animals, is far more mysterious.

The biggest question is why whales sing at all.

“The thing that always gets me out of bed in the morning is the function of the song,” Dr. Noad said. “I find humpback song fascinating from the point of view of how it’s evolved.”

The leading hypothesis is that male humpbacks — only the males sing — are trying to attract females. But they may also switch tunes when another male is nearby, apparently to assess a rival’s size and fitness, said Dr. Noad, who was the senior author of one of four new papers on whale songs.

Why the humpbacks’ musical patterns tend to be more complex than those of other whales is also a bit murky. Dr. Noad suggested that the development may be the result of so-called “runaway selection.”

Early humpbacks with complex songs were so much more successful at mating that they gained a substantial evolutionary advantage over their brethren with simpler vocalizations. This led to some very large, sometimes very noisy animals.

Julien Bonnel, an associate scientist at the Woods Hole Oceanographic Institution in Massachusetts, said the growing research also shows the importance of collecting data over many years, offering insights not only into whales but ocean conditions that affect other species.

Humpback whales feeding with a bubble net in waters off Alaska.CreditKevin Schafer/Minden Pictures

The technology for recording whales has gotten much cheaper over the last dozen years or so, making it more accessible to researchers. And computer programs that analyze huge data sets quickly have helped interpret years of these recordings.

Tagging whales without hurting them has produced more data, Dr. Noad noted, but the tags only remain on the whale for a few hours, limiting the information that can be collected.

In one of the new studies, led by scientists at the New York-based Wildlife Conservation Society, researchers tracked humpbacks singing along the east and west coasts of Africa, comparing songs sung by those off the coast of Gabon to those near Madagascar.

The study, published in the journal Royal Society Open Science, confirmed that the two populations interact, noting overlap in their vocalizations. The researchers recorded songs annually from 2001 to 2005 using hand-held hydrophones aboard boats.

“Male humpback whales within a population tend to sing the same song type, but it’s continuously changing and evolving over time,” said Melinda Rekdahl, the study’s first author and a marine conservation scientist with the wildlife society. “It’s thought to be one of the best examples of cultural evolution in the animal kingdom.”

Dr. Rekdahl wasn’t on the boat that collected the sound for her new study, but she knows firsthand that “it can be an amazing experience,” she said.

The sound of a nearby singer resonates through the hull of the boat. “If the singer is that close, you can hear the song getting fainter just before the whale surfaces nearby,” she recalled.

“If the singers aren’t that close,” she added, “you can often sit there for hours recording and hearing the song through your headphones but not see a whale anywhere.”

Dr. Rekdahl based her new study on data collected between 2001 and 2005, because she thought those recordings offered the best opportunity to compare song similarities between neighboring populations.

The idea of using songs to look at population mixing and connectivity is relatively new, she said, and has only been proven valuable in the last few years.

Some animals repeat sounds more than others, some sing “aberrant” tunes, and juveniles may hum jingles altogether different from the adults’. Humpbacks also alter their tunes over time.

One reason might be novelty — for themselves or nearby females. “If I was swimming up with 15,000 whales and all the males were singing the same song, it would drive me crazy,” Dr. Rekdahl said. Maybe the “females are just, like, give me a new song!”

Two additional recent studies examined how the songs change, seasonally and across years.

In one paper, Jenny Allen, who was a doctoral student with Dr. Noad, found an unexpected pattern among humpbacks. Once their songs reach a certain level of complexity, humpbacks drop that tune entirely and pick up a new, simpler one. Her study, the first to quantify the complexity of the songs, was published in Proceedings of the Royal Society B: Biological Sciences.

“That clear oscillating pattern was something we didn’t really expect,” said Dr. Allen, now a postdoctoral researcher at the University of Queensland and a lecturer at Griffith University in Australia.

Assuming that the songs are meant to attract females, “it might be that a brand-new song is a bit sexier than continuing to sing the complicated version of the old song,” she said. But because it’s hard to memorize a whole new song, “they’re simplifying it to make it easy to learn so much new material all at once.”

Humpback songs have a lot of repeating patterns, which might make them easier to remember, just as rhymes at the end of poetry lines aid memorization, Dr. Allen said. She also found a lot of predictability in the patterns, and compared them to pop songs based on the same four chords.

In another new paper, researchers at the University of Brest in France found that the pitch of Antarctic blue whale, pygmy blue whale and fin whale vocalizations fell from 2007 to 2016 at various recording sites in the southern Indian Ocean.

Because of a whale’s anatomy, a louder call is higher in pitch and a quieter one is lower. Essentially, the whales have gotten slightly quieter, said Emmanuelle Leroy, now a research fellow at the University of New South Wales and an author of the new research.

“Blue whales are mostly solitary, so to communicate across large distance, they need to produce really low-frequency and high-intensity calls,” she said. “The calls are really loud and will propagate over a few hundreds of kilometers.”

Her team has two hypotheses to explain the drop in pitch across years. With the populations rebounding since the end of commercial whaling, perhaps the whales don’t need their calls to carry as far to be heard by others.

Or perhaps with oceans acidifying because of climate change, the calls are naturally carrying farther, allowing the whales to reduce their volume. The team does not believe the change in pitch is tied directly to human activity.

Their research, published in the Journal of Geophysical Research: Oceans, also showed that the call pitch of the Antarctic blue whales varies across seasons, with pitches increasing by .1 hertz during the spring and summer and dropping at other times.

That might be the whales’ response to the loud cleaving of icebergs in the spring and summer. These extremely loud sounds — like the cracking of ice in a glass — make it harder for the whales to hear one another, so they crank up the volume, Dr. Leroy said.

Dr. Noad thinks the overall drop in pitch could be a reflection of the aging of the population, with older whales making deeper sounds.

(Contrary to other scientists, he also believes that whales can hear human-made noises from quite a distance, in the same way that people in urban environments can hear the distant rumble of traffic even if there are no cars passing directly by.)

Humpback whales have made a “really nice comeback” since commercial whaling was largely stopped in the 1960s, Dr. Noad said. But for unknown reasons, blue and fin whales are still struggling; just a few thousand Antarctic blue whales remain.

In yet another new study related to whale song, researchers at Woods Hole found that short-finned pilot whales living off the coast of Hawaii have their own vocal dialects, suggesting that different groups are purposely avoiding one another.

Relatively little is known about this species’ behavior. The new research provides a better sense of the social ties between whale groups, which could promote understanding of their genetic diversity and evolution, as well as conservation, the researchers said.

3136. Macaques Vocal Exchanges Are Similar To Humans

By Katie Brown, Science News, December 31, 2018


Photo credit: Unknown

When polite people talk, they take turns speaking and adjust the timing of their responses on the fly. So do wild macaques, a team of Japanese ethologists reports.

Analysis of 20-minute vocal exchanges involving 15 adult female Japanese macaques (Macaca fuscata) revealed that the monkeys altered their conversational pauses depending on how quickly others answered, the researchers report in a study in an upcoming issue of Current Zoology.

It’s unclear whether the monkeys were actually talking in any way analogous to how humans converse. While macaques have the vocal equipment to form humanlike words, their brains are unable to transform that vocal potential into human talk (SN Online: 12/19/16). The primates instead communicate in grunts, coos and other similar sounds.

But the length of pauses between those grunts and coos closely match the length of pauses in human chats, says coauthor Noriko Katsu of the University of Tokyo.

The researchers analyzed 64 vocal exchanges, called bouts, between at least two monkeys that were recorded between April and October 2012 at the Iwatayama Monkey Park in Kyoto, Japan. The team found that the median length of time between the end of one monkey’s calls and the beginning of another’s was 250 milliseconds — similar to the average 200 milliseconds in conversational pause time between humans. That makes the macaques’ gaps between turns in chattering one of the shortest call-and-response pauses yet measured in nonhuman primates.

The quick response time suggests the macaques are not calling out in habit, but are taking turns and coordinating their vocalizations, says Isaac David Schamberg, a primatologist at Harvard University who was not involved in the study.

“Monkey vocalizations are not static and automatic; they’re dynamic and conversational,” Schamberg says. Vocal pauses were also reported in marmosets in a 2013 study published in Current Biology, but with much longer gaps averaging three to five seconds.

The new study highlights an “area in which monkey vocalizations, studied in their social context, function in some ways like human speech,” says Robert Seyfarth, a primatologist at the University of Pennsylvania who wasn’t involved in the study. Understanding primates’ vocal patterns could help reveal “the conditions under which language might have evolved from the prelinguistic communication of our ancestors.”

3128. Humans Are Using Smells to Influence Nonhuman Animals

Elizabeth Anne Brown, National Geographic, December 12, 2018

The Villagers of Maharashtra state held their breath as the body count climbed.

Animal activists knew her as Avni. The Indian government called her T1. But no one knew quite what to do with the tiger, the mother of two cubs who was blamed for 13 mauling deaths in two years.

The Indian government deployed a small army to bring Avni in. Hundreds of foot soldiers, infrared drones, paragliders, snipers, and elephants combed the jungle fruitlessly for nearly two months. By October, with wiley Avni still at large, it was time to break out the big guns, the final line of defence, the Hail Mary. It was time for Obsession for Men. The cologne by Calvin Klein.

Musky colognes like Obsession tap into an invisible system of animal communication—the information superhighway of scent. Urine, musk, and other excreta can serve as a stinky form of “message in a bottle” to the next animal that comes sniffing, providing crucial information that they use to navigate the world.

Some humans hope to crack the code, and to start leaving our own smell-messages—like Obsession—to purposely influence the behaviour of animals fluent in the language of the nose. And that smells like trouble.

Nose-blind

Blindness and deafness are considered disabilities—but what’s the word for someone who can’t smell?

Humans give scent—arguably the most primal of the senses—short shrift. We outsource our sniffing jobs to canines and do everything we can to suppress our own bodily odours. But from scent alone, humans can identify individuals, assess the relatedness of potential mates, and detect illness.

Big cats wild for Calin Clin cologne? 

June 24, 2010—Wildlife Conservation Society researchers at the Bronx Zoo found that captive cheetahs were attracted to Calvin Klein's "Obsession for Men" fragrance. That and other scents were tested in the wild to see if big cats would approach camera traps used for behavioural studies.

On a conscious level, we’re overwhelmingly visual creatures, so it’s easy to overlook the olfactory landscape—a whole plane of sensory information. But for many animal species, scent is as important as sight and a primary means of communication.

Scent markings work as animal billboards—at the most basic level, they say, “I’m here.” Depending on the sender and the recipient, that can be read as “come find me” or “stay away.”

These messages can be left intentionally for members of the same species—tigers like Avni deposit scent markings to draw territorial boundaries for rivals nearby, while female pandas rub their butts against trees to leave a ‘come-hither’ smell for males when they’re sexually receptive.

Other scent marks are inevitable—everybody poos—and reveal information competitors can easily exploit. Carnivores track rodents by following a breadcrumb trail of feces pellets, and predators like Avni might as well send up a signal flare for prey animals whenever they urinate.

Hijacked scents

As human populations increase exponentially and wild places shrink, animal-human conflict is on the rise—and with it the demand for products to control animal behaviour.

There’s a whole industry providing natural and synthetic animal smells—from bottled bobcat urine to “ground, aged and preserved otter glands, ”it can all be yours, and with free shipping to boot.

Some scent-messages are easy to hijack. Every deer hunter worth her salt knows a bottle of doe urine will bring bucks running to the stand, and since deer don’t have the most discerning palate, a homemade brew of urea, ammonia, and water is close enough to do the trick, according to hunting websites.

Parfumiers used to scrape a foul-smelling secretion straight from the anal glands of civets like this one (Viverricula indica) to give colognes their signature musky scent. Thankfully, there’s a synthetic dupe available now. PHOTOGRAPH BY JOEL SARTORE, NATIONAL GEOGRAPHIC PHOTO ARK

We know how to attract animals—baiting with food, like fresh meat or a salt lick, is a historical favorite—but animal deterrents are harder to come by. Products like Shake-Away DEER claim that powdered coyote urine can conjure the odour-ghost of a coyote to patrol your garden and discourage would-be nibblers—but experts like Michael Parsons, behavioural ecologist at Fordham University, say we shouldn’t bet the farm just yet. We haven’t decoded the whole message.

Forging a Van Goug

Michael H. Parsons must have really good laundry detergent. From Tasmanian devil urine to New York City rat tinkle, he’s spent decades studying animals scents and behaviour.

But after compiling the results of more than 170 studies for a smell state-of-the-union published in Biological Reviews, Parsons marvels at how ignorant we still are of how to read scents. “It’s almost embarrassing,” Parsons admits. “Exciting, but embarrassing. We’re just beginning to find out how many variables are involved.”

Parsons points to his own research experience in Australia, where kangaroos outnumber humans almost three to one and are considered a pest species, “like rats in New York.” Kangaroos don’t have many natural predators—“I mean, these animals are six feet tall and built like Schwarzenegger”—but Parsons observed that the majority react fearfully to scents from dingos, wild dogs that travel the country in packs.

Parsons’ colleague Ken Dods developed an artificial scent dingo scent, a time-release gel that scientists hoped could be used as a broad-scale deterrent for kangaroos. The result couldn’t have been farther from their intention. “The kangaroo bucks were responding angrily to it,” Parsons laughs. “They were trashing the area around it.”

The problem is that would-be Pied Pipers are looking for the short version of smell messages—the “come” or “go.” But it’s impossible to convey that information without getting the context right.

Scent markings are made up of dozens, if not hundreds, of volatile chemicals. Canid species like dogs, wolves, and dingos have between 90 and 180 of these in their urine, according to Parsons—all conspiring to create the smell that reaches the nose.

Each chemical doesn’t just add to the positive or negative valence of the overall smell—good or bad, come or go—they can also provide layers of information to the right sniffer. It’s a laundry list of variables: individual identity, sex, social ranking, clan or pack membership, relatedness, health, reproductive status, and even how hungry the animal is. Those are just the ones we know of so far, Parsons emphasises.

It’s easy to get that context wrong when mass-producing animal scents. Apart from ethical concerns, harvesting urine from animals in captivity is full of pitfalls. Take the example of a coyote—prey animals like elk find scent markings from dominant animals frightening, while scents from subordinates and females may not break their stride. Does that mean captive coyotes need to be housed in a group setting to get the mix right in their urine? And since diet is such a defining factor in the, uh, content of excreta, how close to “natural” does it have to be for the scent to work?

We understand the general shape of how these odour messages are supposed to look. But the lives of scent-dependent animals literally depend on having the trained nose of a urine sommelier. Fabricating artificial scent messages is like trying to forge a Van Gogh without even knowing which colours were used.

Even if you get all the animal-side variables aligned, chemistry does not work in your favour. As soon as the scent leaves the body, everything from differential evaporation to weather conditions begin to degrade the scent. That’s how rabbits can tell when the big bad wolf was in the area, which indicates just how concerned they should be. So that stale, long-bottled fox urine may not be enough to spook the chipmunks into the neighbour’s yard.

“If you find a scent that works, you have to freeze-frame it on the spot,” Parsons explains. “By the time you store it in the lab, it may degrade and be very different.” In fact, the very act of freezing a pheromone for transportation or storage has been demonstrated to alter behavioural responses.

Of course, none of the above matters if you’re trying to pull the wool over the nose of a particularly clever animal. Like Avni.

Obsession

Slinking through the undergrowth of African and Asian forests is the civet, a small-bodied mammal that looks like the illicit lovechild of a racoon and a housecat. Its anal glands secrete a foul-smelling goo that most would associate with tomcat spray—and that Calvin Klein, evidently, associates with attractive men.

Civets love organic smells

With their sense of scent, you might call civets the perfume purveyors of the natural world.

In the early days of Obsession for Men, the cologne by Calvin Klein, its signature musky odour was scraped directly from the butts of captive civets. Thankfully for the civets—and better for Calvin Klein’s PR department—there’s a synthetic mimic manufactured from palm oil available now. Calvin Klein hoped to tap into the primal desires of women—but it turns out his cologne resonated with a much larger demographic.

John Goodrich, chief scientist at big cat conservation NGO Panthera and director of the Tiger Forever program, remembers the first time he saw a cat catch a whiff of Obsession, on a tour of the Omaha Zoo more than a decade ago.

“They’d go crazy, they’d be rubbing up against it,” Goodrich recalls. “They would come up to the bars wanting it sprayed in their face.”

Conservation researchers at the Bronx Zoo identified Obsession as a promising candidate for luring cats to cameras for wildlife surveys. “These big cats would wrap their arms around a tree and just vigorously rub up and down,” Pat Thomas, then the Bronx Zoo’s general curator, explained to National Geographic in 2010. “Sometimes they would start drooling, their eyes would half-close—almost like they were going into a trance.”

Goodrich was eager to bring Obsession to the rocky Sikhote-Alin mountain range of Russia, where he hoped to gather more data in his study of Siberian tigers. “I thought, wow! This is just what we need,” Goodrich remembers. “We’re going to catch tons of tigers now.”

But the words of one particularly strange Obsession commercial from 1985—“Was it me? Did I somehow drive her away?”—would prove prophetic. “We were just better off putting the camera traps in places where tigers normally went and were scent-marking themselves,” Goodrich explains. “The tigers in Russia either avoided it or just didn’t care.”

Some field researchers swear by Obsession. Miguel Ordeñana, a biologist at the Natural History Museum of Los Angeles, credits the cologne with increasing traffic around camera traps for jaguars in Nicaragua. He suspects the cats interpret the scent as a territorial marking from rivals—so why weren’t the Russian tigers intrigued?

Scientists speculate that cats react differently to Obsession and other musky colognes based on prior experience. Naïve cats like captive-born leopards and tigers are nearly always interested in novel stimuli—enrichment treats from zoo keepers tend not to be dangerous—whereas wild cats may interpret a mysterious new smell as a red flag to be avoided.

What’s more, a cat’s response may also depend on how closely civetone (the chemical dupe in Obsession) resembles the chemical structure of their own scent markings, which vary considerably across species.

A CLEVER CAT

Coyote urine is often marketed as a natural pest deterrent. Some users swear that a quick sprinkle around the garden is enough to discourage would-be nibblers.PHOTOGRAPH BY TOM MURPHY, NAT GEO IMAGE COLLECTION

The plan was to tranquillise Avni and her two cubs for assessment by a vet and possible relocation to a rehabilitation centre or release into a more sparsely populated area. That was best-case scenario. But after much debate, India’s Supreme Court had also given wildlife managers carte blanche to “shoot to kill” if the situation turned violent.

If the team could distract Avni for long enough with Obsession—the zoo record was 11.1 minutes—the tranquillisers might have time to kick in, and Avni’s life could be saved.

But it was not to be—Avni didn’t take the bait. “She was too clever for the cologne,” said Asgar Ali Khan, a business management graduate controversially tapped to lead the hunt. “We were dealing with an extraordinarily smart tiger.”

Nawab Shafat Ali Khan, a renowned tiger hunter and Asgar Ali Khan’s father, explained to the New York Times that he was convinced Avni would never be taken alive. “She has learned from all these botched capture operations. We’ve made her very smart. Brilliant, actually.”

Just days later, on Friday November 2, Asgar Ali Khan would shoot and kill Avni in what he described as self-defense—though autopsy reports counter that narrative. Animal rights group across India have decried the killing as a flagrant violation of the law.

The tiger’s case is a high-profile example of how scent is creeping into the mainstream in wildlife management. Though cologne couldn’t save Avni, scientists like Parsons remain optimistic that artificial scent messages will one day help resolve conflict peacefully when animals and humans clash—though replacing fences with feces may be a hard sell at first.

1637. Why Some Mammal Species Kill Their Infants?

By Carl Zimmer, The New York Times, November 13, 2014

In the early 1970s, Sarah Blaffer Hrdy, then a graduate student at Harvard, traveled to India to study Hanuman langurs, monkeys that live in troops, each made up of several females and a male.

From time to time, Dr. Hrdy observed a male invade a troop, driving off the patriarch. And sometimes the new male performed a particularly disturbing act of violence. He attacked the troop’s infants.

There had been earlier reports of infanticide by adult male mammals, but scientists mostly dismissed the behavior as an unimportant pathology. But in 1974, Dr. Hrdy made a provocative counter proposal: infanticide, she said, is the product of mammalian evolution. By killing off babies of other fathers, a male improves his chances of having more of his own offspring.

Dr. Hrdy went on to become a professor at the University of California, Davis, and over the years she broadened her analysis, arguing that infanticide might well be a common feature of mammalian life. She spurred generations of scientists to document the behavior in hundreds of species.

“She’s the goddess of all this stuff,” said Kit Opie, a primatologist at University College London.

Forty years after Dr. Hrdy’s initial proposal, two evolutionary biologists at the University of Cambridge have surveyed the evolution of infanticide across all mammals. In a paper published Thursday in Science, the scientists concluded that only certain conditions favor the evolution of infanticide — the conditions that Dr. Hrdy had originally proposed.

“My main comment is, ‘Well done,'” said Dr. Hrdy. She said the study was particularly noteworthy for its scope, ranging from opossum to lions.

The authors of the new study, Dieter Lukas and Elise Huchard, started by plowing through the scientific literature, looking for evidence of infanticide in a variety of mammalian species. The researchers ended up with data on 260 species, and in 119 of them — over 45 percent — males had been observed killing unrelated young animals.

Dr. Lukas and Dr. Huchard then looked at how infanticide might have evolved over the past 160 million years of mammal evolution. “When we started, we weren’t sure if infanticide was present in some ancestral mammal and is just more pronounced in some species and is lost in other species,” said Dr. Lukas. “Or maybe it just evolved in those species where the conditions were right.”

Their research supports the second scenario. The common ancestor of living mammals did not practice infanticide: The behavior evolved later and independently in a number of separate animal lineages.

Dr. Lukas and Dr. Huchard found that the species that evolved infanticide had a few things in common. For instance, the females tended to give birth year-round, rather than at just one time of the year. Another key factor was that males and females lived in groups where females greatly outnumber males.

The scientists concluded that conditions such as these fostered the evolution of infanticide. If only a few males get to mate with females, there will be a lot of other males facing the prospect of dying childless. Natural selection will favor males that can take over groups of females.

But these males are pressed for time. It won’t be too long before another male threatens them with exile. Meanwhile, many females will be busy nursing infants. Killing the offspring of other males can free up females for reproduction and widen the window of opportunity for new males, leading to more offspring for them.

The researchers also noted that infanticide generally did not evolve in species where females only give birth once a year. “There’s no sense for a male to kill the offspring in the previous year, because he has to wait anyway,” said Dr. Lukas.

Dr. Hrdy and other early infanticide researchers not only investigated how infanticide might have evolved. They also suggested that mothers and fathers had evolved defenses against infanticidal males.

Dr. Lukas and Dr. Huchard found support for this idea, too. In species in which infanticide appeared, females gradually mate with more and more males. This behavior may protect infants by introducing uncertainty: Males might be more reluctant to kill infants if one of them could be his own.

“In effect, whenever promiscuity is high enough, it does not pay for males to commit infanticide,” said Carel P. Van Schaik, a primatologist at the University of Zurich. “This new study beautifully confirms the major role of sexual behavior.”

Despite its sweep, , the new study doesn’t settle every debate over infanticide. Dr. Van Schaik, for example, suspects that the true number of infanticidal species is higher. In some of them, defenses against the practice have become so effective that infanticide has become rare, and therefore hard for scientists to observe.

The new study also clashes with earlier work finding that infanticide altered the social structure of some species. Last year, for example, Dr. Opie and his colleagues reported that monogamy — in which one male and one female lived together — has evolved in primates as a defense against infanticide.

In their new study, Dr. Lukas and Dr. Huchard found no such pattern. Dr. Opie believes that is partly because they didn’t take into account the full diversity of how mammals mate.

“What we’re saying is that infanticide is driving monogamy, and we don’t think anything they’ve shown in this paper contradicts that,” said Dr. Opie.

Among the mammal species that Dr. Lukas and Dr. Huchard didn’t include in their study was our own. Dr. Lukas said the cultural diversity of humans means it is hard to make blanket statements about them. “For many social behaviors, it’s very difficult to define a human universal,” said Dr. Lukas.

That’s not to say that adults never harm — or even kill — children. But Dr. Hrdy argued that the infanticide she documented in langurs — in which males stalked babies for days —was fundamentally different from what happens in our own species.

“A male would have to pull out a butcher knife and stab the baby, but that’s not what you’re seeing,” said Dr. Hrdy. “I don’t think langur infanticide tells us much. I think it’s a very different phenomenon.”

1614. Chimpanzees Plan Ahead for a Good Breakfast (Do You?)

By Science Daily, October 28, 2014

This young male chimp climbing a fig tree risked travel in the dark when predators were active to obtain the more desired, less abundant figs for breakfast. Photo: Karline R. L. Janmaat/Max Planck Institute

New research by the University of California, Davis, shows that chimpanzees plan ahead, and sometimes take dangerous risks, to get to the best breakfast buffet early.

The study co-authored by Leo Polansky, an associate researcher in the UC Davis anthropology department, reveals that chimpanzees will find a place to sleep en route to breakfast sites and risk travel in the dark when predators are active to obtain more desired, less abundant fruits such as figs. The study is being published in the Proceedings of the National Academy of Sciences.

"As humans we are familiar with the race against birds for our cherries, or against squirrels for our walnuts and pecans," Polansky said, "but this race is carried out amongst competitors of all kinds of species in locations all over the world.”

The study provides evidence that chimpanzees flexibly plan their breakfast time, type and location after weighing multiple disparate pieces of information.

"Being able to reveal the role of environmental complexity in shaping cognitive-based behavior is especially exciting," Polansky said. "Long-term, detailed information from the field can reveal the value of high levels of cognition and behavioral flexibility for efficiently obtaining critical food resources in complex environments.”

Researchers recorded when and where five adult female chimpanzees spent the night and acquired food for 275 days during three fruit-scarce periods. The research took place in the Taï National Park in Côte d'Ivoire, led by researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where Polansky was a postdoctoral researcher. His research interests are in both animal behavior and plant phenology.

Story Source:
The above story is based on materials provided by University of California - Davis. Note: Materials may be edited for content and length.
end story_source

Journal Reference:

1 K. R. L. Janmaat, L. Polansky, S. D. Ban, C. Boesch. Wild chimpanzees plan their breakfast time, type, and location. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1407524111

1582. Birds: Caw vs. Croak: Inside the Calls of Crows and Ravens

By The Cornell Lab of Ornithology, September 15, 2014 




What if they are silent?  

There are some visual guidelines.  

1581. Killer Whales Learn to Communicate Like Dolphins

By Science Daily, October 7, 2014

Killer whales are known to attack and kill dolphins, their evolutionary cousins

From barks to gobbles, the sounds that most animals use to communicate are innate, not learned. However, a few species, including humans, can imitate new sounds and use them in appropriate social contexts. This ability, known as vocal learning, is one of the underpinnings of language.

Vocal learning has also been observed in bats, some birds, and cetaceans, a group that includes whales and dolphins. But while avian researchers have characterized vocal learning in songbirds down to specific neural pathways, studying the trait in large marine animals has presented more of a challenge.

Now, University of San Diego graduate student Whitney Musser and Hubbs-SeaWorld Research Institute senior research scientist Dr. Ann Bowles have found that killer whales (Orcinus orca) can engage in cross-species vocal learning: when socialized with bottlenose dolphins, they shifted the types of sounds they made to more closely match their social partners. The results, published in The Journal of the Acoustical Society of America, suggest that vocal imitation may facilitate social interactions in cetaceans.

Killer whales have complex vocal repertoires made up of clicks, whistles and pulsed calls -- repeated brief bursts of sound punctuated with silence. The acoustic features of these vocalizations, such as their duration, pitch and pulse pattern, vary across social groups. Whales that are closely related or live together produce similar pulsed calls that carry vocal characteristics distinct to the group, known as a dialect.

"There's been an idea for a long time that killer whales learn their dialect, but it isn't enough to say they all have different dialects so therefore they learn. There needs to be some experimental proof so you can say how well they learn and what context promotes learning," said Bowles.

Testing vocal learning ability in social mammals usually requires observing the animal in a novel social situation, one that might stimulate them to communicate in new ways. Bottlenose dolphins provide a useful comparison species in this respect: they make generally similar sounds but produce them in different proportions, relying more on clicks and whistles than the pulsed calls that dominate killer whale communication.

"We had a perfect opportunity because historically, some killer whales have been held with bottlenose dolphins," said Bowles. By comparing old recordings of vocalization patterns from the cross-socialized subjects with recordings of killer whales and bottlenose dolphins housed in same-species groups, Bowles and her team were able to evaluate the degree to which killer whales learned vocalization patterns from their cross-species social partners.

All three killer whales that had been housed with dolphins for several years shifted the proportions of different call types in their repertoire to more closely match the distribution found in dolphins -- they produced more clicks and whistles and fewer pulsed calls. The researchers also found evidence that killer whales can learn completely new sounds: one killer whale that was living with dolphins at the time of the experiment learned to produce a chirp sequence that human caretakers had taught to her dolphin pool-mates before she was introduced to them.

Vocal learning skills alone don't necessarily mean that killer whales have language in the same way that humans do. However, they do indicate a high level of neural plasticity, the ability to change circuits in the brain to incorporate new information. "Killer whales seem to be really motivated to match the features of their social partners," said Bowles, though the adaptive significance of the behavior is not yet known.

There are immediate reasons to study the vocal patterns of cetaceans: these marine mammals are threatened by human activities through competition for fishery resources, entanglement in fishing gear, collisions with vessels, exposure to pollutants and oil spills and, ultimately, shrinking habitats due to anthropogenic climate change. If their social bonds are closely linked to their vocalizations, killer whales' ability to survive amidst shifting territories and social groups may be tied to their ability to adapt their communication strategies.

"It's important to understand how they acquire [their vocalization patterns], and lifelong, to what degree they can change it, because there are a number of different [cetacean] populations on the decline right now," said Bowles. "And where killer whales go, we can expect other small whale species to go -- it's a broader question.”

Story Source:

The above story is based on materials provided by Acoustical Society of America (ASA). Note: Materials may be edited for content and length.

Journal Reference:

1. Whitney B. Musser, Ann E. Bowles, Dawn M. Grebner, and Jessica L. Crance. Differences in acoustic features of vocalizations produced by killer whales cross-socialized with bottlenose dolphins. The Journal of the Acoustical Society of America, 2014 DOI: 10.1121/1.4893906