by Anil Ananthaswamy THINK for a moment about a time before you were born. Where were you? Now think ahead to a time after your death. Where will you be? The brutal answer is: nowhere. Your life is a brief foray on Earth that started one day for no reason and will inevitably end. But what a foray. Like the whole universe, your consciousness popped into existence out of nothingness and has evolved into a rich and complex entity full of wonder and mystery. Contemplating this leads to a host of mind-boggling questions. What are the odds of my consciousness existing at all? How can such a thing emerge from nothingness? Is there any possibility of it surviving my death? And what is consciousness anyway? Answering these questions is incredibly difficult. Philosopher Thomas Nagel once asked, "What is it like to be a bat?" Your response might be to imagine flying around in the dark, seeing the world in the echoes of high-frequency sounds. But that isn't the answer Nagel was looking for. He wanted to emphasise that there is no way of knowing what it is like for a bat to feel like a bat. That, in essence, is the conundrum of consciousness. Neuroscientists and philosophers fall into two broad camps. One thinks that consciousness is an emergent property of the brain and that once we fully understand the intricate workings of neuronal activity, consciousness will be laid bare. The other doubts it will be that simple. They agree that consciousness emerges from the brain, but argue that Nagel's question will always remain unanswered: knowing every detail of a bat's brain cannot tell us what it is like to be a bat. This is often called the "hard problem" of consciousness, and seems scientifically intractable - for now. © Copyright Reed Business Information Ltd.

Keyword: Attention
Link ID: 15632 - Posted: 07.30.2011

by Cian O'Luanaigh Here's a piece of good news for people who have had a gastric bypass – not only will you eat less, you may also start to eat more healthily. The most common form of bariatric – anti-obesity – surgery is the "Roux-en-Y" gastric bypass, which involves stapling the stomach so a small pouch is made at the top, which is then connected directly to the small intestine. This bypasses most of the stomach and the duodenum so the patient feels full quicker. The vertical-banded gastroplasty is an alternative technique which reduces the volume of the stomach without bypassing any part of the intestine, restricting how much the patient can eat at any one time. After people undergo gastric bypass operations, it is not uncommon for them to report that their eating habits have changed. To investigate these claims, Carel le Roux and colleagues from Imperial College London asked 16 people who had undergone either type of bariatric surgery six years before to fill in a survey about their dietary preferences after the operation. People who had had a gastric bypass reported eating a lower proportion of fat after surgery than those with a vertical-banded gastroplasty. To find out why this was so, the team carried out either a gastric bypass or a sham operation on 26 rats. © Copyright Reed Business Information Ltd.

Keyword: Obesity; Hormones & Behavior
Link ID: 15631 - Posted: 07.30.2011

by Andy Coghlan A hereditary form of blindness has been delayed or reversed for the first time by a daily drug treatment. The drug is the first to benefit people with a disease of their mitochondria, the energy powerhouses of cells. There had been no way to halt the rapid onset of blindness in people with the most common mitochondrial disease, called Leber's hereditary optic neuropathy. It strikes men in their twenties, leading to total blindness within three to six months of the first symptoms appearing. But after receiving a drug called idebenone for six months, some people whose sight had begun to deteriorate reported drastic improvements in their vision that continued after the trial ended. In the trial, 55 people received idebenone and 30 were given a placebo. After six months, 11 people who received idebenone could read an extra two lines on a standard vision chart – and nine people who could not read any letters at the outset could by the end. "This is not a cure, but it's a significant effect," says team leader Patrick Chinnery of Newcastle University in the UK. It is also the first time that an inherited mitochondrial disease has been successfully treated. "This trial tells us there's hope for this and other mitochondrial diseases," says Chinnery. © Copyright Reed Business Information Ltd.

Keyword: Vision
Link ID: 15630 - Posted: 07.30.2011

By Rachael Rettner Amy Winehouse's family has reportedly said the singer may have died from alcohol withdrawal. The family believes withdrawal may have induced fatal seizures in the singer, according to Entertainment Weekly. But is it really possible to die from alcohol withdrawal? Yes, experts say — though it's not common. "Somebody who's been a drinker and consumed a lot of alcohol for a number of years probably could have severe seizures," said Dr. Robert Schwartz, chairman of family medicine at the University of Miami Miller School of Medicine. Such seizures may cause an individual to aspirate food (inhale it through the trachea) that comes up from their stomach, possibly leading to choking and death, Schwartz said. Hitting your head during a seizure can also be lethal. Common withdrawal symptoms from alcohol include difficulty sleeping, sweating and heart palpitations. Withdrawal can also cause delirium, hallucinations, rapid heart rate, high blood pressure and hyperventilation, Schwartz said. Alcohol is toxic to the body, causing changes to a person's metabolism and central nervous system, Schwartz said. But the body of an alcoholic has adapted to this new environment, Schwartz said. So abstaining from the drug completely can be dangerous. "Your body develops a homeostasis with alcohol," Schwartz said. "As soon as you take it away, you're upsetting that balance," Schwartz said. © 2011 msnbc.com

Keyword: Drug Abuse
Link ID: 15629 - Posted: 07.30.2011

By Cari Nierenberg It's truly a sob story for those prone to waterworks displays: Shedding tears only improved mood in one-third of cryers who kept tabs of their bawling behaviors, finds recent research. Apparently weeping isn't the cathartic emotional release it's often cracked up to be, sniff, sniff. Please pass the tissues. Science has previously looked into boo-hooing with mixed results: After viewers in a lab setting watched a sad film clip, weeping was rarely found to boost mood -- but this might not be the best place to burst into heartfelt tears. Other studies have asked participants to recall past crying episodes. But retrospective surveys might not necessarily reflect actual behavior since memory can be selective, and people might not remember those times when wailing made them feel worse. This new study, currently published online in the Journal of Research in Personality, asked 97 women aged 18 to 48 in the Netherlands to keep a daily crying and mood diary over a two-to three-month period. Men were not included in this experiment because the data was originally collected as part of a larger trial exploring the link between crying and the menstrual cycle. Each night, participants logged their daily mood, their urge to cry, and whether they shed any tears. If they wept, they kept further details of each sob session, such as the reason for it, how long it lasted, how intensely they bawled, where it occurred, whether other people were around and how they felt afterward. © 2011 msnbc.com

Keyword: Emotions
Link ID: 15628 - Posted: 07.30.2011

NIH-funded scientists have developed a strain of mice with a built-in off switch that can selectively shut down the animals’ serotonin-producing cells, which make up a brain network controlling breathing, temperature regulation, and mood. The switch controls only the serotonin-producing cells, and does not affect any other cells in the animal’s brains or bodies. When the researchers powered down the animals’ serotonin cells, the animals failed to sufficiently step up their breathing to compensate for an increase of carbon dioxide in the air, and their body temperatures dropped to match the surrounding temperature. The finding has implications for understanding sudden infant death syndrome, or SIDS, which has been linked to low serotonin levels, and is thought to involve breathing abnormalities and problems with temperature control. The finding may also provide insight into depressive disorders, which also involve serotonin metabolism. The study results appear in the current issue of the journal Science. SIDS is the death of an infant before his or her first birthday that cannot be explained after a complete autopsy, an investigation of the scene and circumstances of the death, and a review of the medical history of the infant and of his or her family. According to the National Center for Health Statistics, SIDS is the third leading cause of infant death. To conduct the study, the researchers developed mice with a unique molecule, or receptor, on the surface of their serotonin-producing brain cells, or neurons. Typically, cells communicate via chemicals that bind to receptors on their surfaces, with the molecules binding to their receptors in much the same way a key fits into a lock.

Keyword: Sleep
Link ID: 15627 - Posted: 07.30.2011

When people recognize voices, part of what helps make voice recognition accurate is noticing how people pronounce words differently. But individuals with dyslexia don't experience this familiar language advantage, say researchers. The likely reason: "phonological impairment." Tyler Perrachione with the Massachusetts Institute of Technology explains, "Even though all people who speak a language use the same words, they say those words just a little bit differently from one another--what is called 'phonetics' in linguistics." Phonetics is concerned with the physical properties of speech. Listeners are sensitive to phonetic differences as part of what makes a person's voice unique. But individuals with dyslexia have trouble recognizing these phonetic differences, whether a person is speaking a familiar language or a foreign one, Perrachione says. As a Ph.D. candidate in Neuroscience at MIT, Perrachione recently examined the impacts of phonological impairment through experiments funded by the National Science Foundation's Directorate for Education and Human Resources. He and colleague Stephanie Del Tufo as well as Perrachione's MIT research advisor John Gabrieli hypothesized that if voice recognition by human listeners relies on phonological knowledge, then listeners with dyslexia would be impaired when identifying voices speaking their native language as compared to listeners without dyslexia. © 2011 U.S.News & World Report LP

Keyword: Dyslexia; Language
Link ID: 15626 - Posted: 07.30.2011

by Michael Balter "This town ain't big enough for the both of us," says ranch foreman Nick Grindell to lawman Tim Barrett in the 1932 film The Western Code. Biologists know the principle well: Two animal species can rarely occupy the same niche. The same, it seems, goes for human populations. A new study of Neandertal and modern human sites in the south of France concludes that the moderns so greatly outnumbered their evolutionary cousins that Neandertals had little choice but to go extinct. For more than 100,000 years, Neandertals had Europe all to themselves. Then, beginning roughly 40,000 years ago, modern humans—Homo sapiens—began migrating into the continent from Africa. Although researchers debate how long the Neandertals hung around, these ancient humans probably did not survive much longer than 5000 years. Just why they disappeared is also a matter of contention, but most experts agree that H. sapiens was able to outgun its rival in either direct or indirect competition for food and other resources. Some genetic studies, based on both modern and ancient DNA sequences, have suggested that modern human population growth quickly outstripped that of Neandertals, but estimating population levels from these kinds of data is very difficult and inexact. So Paul Mellars and Jennifer French, archaeologists at the University of Cambridge in the United Kingdom, decided to look directly at the archaeological evidence for the presence of both groups in the region where the most excavations have taken place: southwestern France, including the lush Dordogne region, as well known for its prehistoric sites as for its wine and foie gras. © 2010 American Association for the Advancement of Science

Keyword: Evolution
Link ID: 15625 - Posted: 07.30.2011

By John Matson After an echolocating bat locks on to an insect with its sonar beam, it can keep track of its prey despite receiving a slew of echoes from other objects—leaves, vines and so on. How does it separate echoes bouncing off its target from echoes bouncing off the surrounding clutter, especially when the echoes reach the bat at the same time? The key, according to a new study of echolocation in the big brown bat (Eptesicus fuscus), is that objects in a bat's sonar beam produce echoes of a different character depending on where they fall within the beam. The bat can focus on the echoes from the center of the beam, where their target lies, and discount those from clutter on the periphery. The study appears in the July 29 issue of Science. The distinction is enabled by the fact that the bats' sonar pulses have two distinct components, or harmonics, at different frequency levels. The higher-frequency harmonic forms a narrower beam than the widespread low harmonic, so central targets receive and reflect both harmonics in roughly equal measure. Off-target objects, on the other hand, fall outside the narrower beam of the high harmonic and thus reflect proportionally more of the low-frequency sounds. The harmonic structure also assists in isolating insect targets from background reflections—higher-frequency sounds diminish more quickly in air, so the high harmonic returns to the bat more weakly when reflected off of distant objects. © 2011 Scientific American

Keyword: Hearing
Link ID: 15624 - Posted: 07.30.2011

by Carl Zimmer In 1758 the Swedish taxonomist Carolus Linnaeus dubbed our species Homo sapiens, Latin for “wise man.” It’s a matter of open debate whether we actually live up to that moniker. If Linnaeus had wanted to stand on more solid ground, he could have instead called us Homo megalencephalus: “man with a giant brain.” Regardless of how wisely we may use our brains, there’s no disputing that they are extraordinarily big. The average human brain weighs in at about three pounds, or 1,350 grams. Our closest living relatives, the chimpanzees, have less than one-third as much brain—just 384 grams. And if you compare the relative size of brains to bodies, our brains are even more impressive. As a general rule, mammal species with big bodies tend to have big brains. If you know the weight of a mammal’s body, you can make a fairly good guess about how large its brain will be. As far as scientists can tell, this rule derives from the fact that the more body there is, the more neurons needed to control it. But this body-to-brain rule isn’t perfect. Some species deviate a little from it. A few deviate a lot. We humans are particularly spectacular rule breakers. If we were an ordinary mammal species, our brains would be about one-sixth their actual size. Competing theories seek to explain the value of a big brain. One idea, championed by psychologist Robin Dunbar of the University of Oxford, is that complicated social lives require big brains (pdf). A relatively large-brained baboon can make a dozen alliances while holding grudges against several rivals. Humans maintain far more, and more complicated, relationships. © 2011, Kalmbach Publishing Co.

Keyword: Evolution
Link ID: 15623 - Posted: 07.28.2011

By GRETCHEN REYNOLDS For those of us hoping to keep our brains fit and healthy well into middle age and beyond, the latest science offers some reassurance. Activity appears to be critical, though scientists have yet to prove that exercise can ward off serious problems like Alzheimer’s disease. But what about the more mundane, creeping memory loss that begins about the time our 30s recede, when car keys and people’s names evaporate? It’s not Alzheimer’s, but it’s worrying. Can activity ameliorate its slow advance — and maintain vocabulary retrieval skills, so that the word “ameliorate” leaps to mind when needed? Obligingly, a number of important new studies have just been published that address those very questions. In perhaps the most encouraging of these, Canadian researchers measured the energy expenditure and cognitive functioning of a large group of elderly adults over the course of two to five years. Most of the volunteers did not exercise, per se, and almost none worked out vigorously. Their activities generally consisted of “walking around the block, cooking, gardening, cleaning and that sort of thing,” said Laura Middleton, an associate professor at the University of Waterloo in Ontario and lead author of the study, which was published last week in Archives of Internal Medicine. But even so, the effects of this modest activity on the brain were remarkable, Dr. Middleton said. While the wholly sedentary volunteers, and there were many of these, scored significantly worse over the years on tests of cognitive function, the most active group showed little decline. About 90 percent of those with the greatest daily energy expenditure could think and remember just about as well, year after year. © 2011 The New York Times Company

Keyword: Alzheimers
Link ID: 15622 - Posted: 07.28.2011

Post traumatic stress disorder (PTSD) is a risk factor for premature birth, research suggests. A study of more than 800 women in the US also found a link with having a smaller baby. Babies of women with the anxiety disorder, triggered by a harrowing event, weighed about half a pound less than usual. Researchers at the University of Michigan, US, say PTSD needs to be taken into account in maternity care. Nearly half of the women in the study were African American. Lead researcher Julia Seng, Professor of Nursing at the University of Michigan, said: "An African American infant in Michigan is 70% more likely to be born prematurely than an infant of any other race. "Therefore PTSD, which is treatable and affects African Americans more widely, may be an additional explanation for adverse perinatal outcomes. "It is essential that outcomes are improved in this high-risk group of women. Maternity care needs to take traumatic stress into account with awareness being raised amongst health workers." BBC © 2011

Keyword: Stress; Development of the Brain
Link ID: 15621 - Posted: 07.28.2011

by Rebecca Coffey 1 Think about money, work, economic outlook, family, and relationships. Feeling anxious? In a 2010 American Psychological Association survey [pdf], those five factors were the most often cited sources of stress for Americans. 2 Stress is strongly tied to cardiac disease, hypertension, inflammatory diseases, and compromised immune systems, and possibly to cancer. 3 And stress can literally break your heart. Takotsubo cardiomyopathy, or “broken heart syndrome,” occurs when the bottom of the heart balloons into the shape of a pot (a tako-tsubo) used in Japan to trap octopus. It’s caused when grief or another extreme stressor makes stress hormones flood the heart. advertisement | article continues below 4 The hormone cortisol is responsible for a lot of these ill effects. Elevated cortisol gives us a short-term boost but also suppresses the immune system, elevates blood sugar, and impedes bone formation. 5 Even the next generation pays a price: Researchers at the University of California, San Francisco, find an association between high cortisol in mothers during late pregnancy and lower IQs in their children at age 7. 6 Stress during pregnancy has also been linked to offspring with autism. 7 But enough stressing! One way to relax: a career of mild obsolescence. Surveying 200 professions, the site CareerCast.com rated bookbinder the least stressful job of 2011. (Most stressful: firefighter and airline pilot.) © 2011, Kalmbach Publishing Co.

Keyword: Stress
Link ID: 15620 - Posted: 07.28.2011

By Judith Burns Science reporter, BBC News Humans living at high latitude have bigger eyes and bigger brains to cope with poor light during long winters and cloudy days, UK scientists have said. The Oxford University team said bigger brains did not make people smarter. Larger vision processing areas fill the extra capacity, they write in the Royal Society's Biology Letters journal. The scientists measured the eye sockets and brain volumes of 55 skulls from 12 populations across the world, and plotted the results against latitude. Lead author Eiluned Pearce told BBC News: "We found a positive relationship between absolute latitude and both eye socket size and cranial capacity." The team, from the Institute of Cognitive and Evolutionary Anthropology, used skulls dating from the 1800s kept at museums in Oxford and Cambridge. The skulls were from indigenous populations ranging from Scandinavia to Australia, Micronesia and North America. Largest brain cavities The largest brain cavities came from Scandinavia, while the smallest were from Micronesia. BBC © 2011

Keyword: Evolution
Link ID: 15619 - Posted: 07.28.2011

By Nadia Drake Fleeing fish beware: The Guiana dolphin has a super Spidey sense. But instead of danger, the dolphin detects faint electrical fields generated by such things as contracting muscles, a beating heart and pumping gills — telltale signs of potential prey. The dolphin is the first true mammal with these super sensory powers, scientists report. It detects electrical fields using organs on its snout that were once considered simple remnants of long-lost whiskers. Electroreception — the ability to sense these bioelectric fields — has already been described in sharks, amphibians, fish and some egg-laying mammals. “We were really surprised to find this in the dolphin. Nobody had expected it,” says sensory biologist Wolf Hanke of the University of Rostock in Germany. Hanke and his team first suspected the Guiana dolphin (Sotalia guianensis) had electropowers based on the size of organs called vibrissal crypts on its snout. Earlier work suggested the crypts, shaped like pits, have a rich blood supply. “We thought they must have some function — they were pretty big — and otherwise would have disappeared during evolution,” Hanke says of the crypts. When the team considered the dolphins’ lifestyle, the idea became even more plausible. Scientists think the dolphins, which live off the eastern edge of Central and South America, are benthic feeders, gulping fish from the seafloor. The resulting plumes of sediment can limit visibility and echolocation, meaning a different way of detecting prey would be especially helpful. © Society for Science & the Public 2000 - 2011

Keyword: Pain & Touch; Evolution
Link ID: 15618 - Posted: 07.28.2011

By Sander van der Linden For centuries people have pondered the meaning of dreams. Early civilizations thought of dreams as a medium between our earthly world and that of the gods. In fact, the Greeks and Romans were convinced that dreams had certain prophetic powers. While there has always been a great interest in the interpretation of human dreams, it wasn’t until the end of the nineteenth century that Sigmund Freud and Carl Jung​ put forth some of the most widely-known modern theories of dreaming. Freud’s theory centred around the notion of repressed longing -- the idea that dreaming allows us to sort through unresolved, repressed wishes. Carl Jung (who studied under Freud) also believed that dreams had psychological importance, but proposed different theories about their meaning. Since then, technological advancements have allowed for the development of other theories. One prominent neurobiological theory of dreaming is the “activation-synthesis hypothesis,” which states that dreams don’t actually mean anything: they are merely electrical brain impulses that pull random thoughts and imagery from our memories. Humans, the theory goes, construct dream stories after they wake up, in a natural attempt to make sense of it all. Yet, given the vast documentation of realistic aspects to human dreaming as well as indirect experimental evidence that other mammals such as cats also dream, evolutionary psychologists have theorized that dreaming really does serve a purpose. In particular, the “threat simulation theory” suggests that dreaming should be seen as an ancient biological defence mechanism that provided an evolutionary advantage because of its capacity to repeatedly simulate potential threatening events – enhancing the neuro-cognitive mechanisms required for efficient threat perception and avoidance. © 2011 Scientific American,

Keyword: Sleep
Link ID: 15617 - Posted: 07.28.2011

By David Biello A drink of alcohol, any kind; "rails" of white powder; a pill prescribed by a pediatrician to assist with attention deficit disorder. Whatever the poison, addiction can take a powerful toll. Nor is it limited to drugs—food, sex and even death-defying stunts can exert the same pull. But it seems to be a particular breed of person who succumbs to addiction, most recently exemplified by the late singer Amy Winehouse​. She joins the "27 Club" of rock stars who died, via addictive behavior, too young—Kurt Cobain, Jimi Hendrix, Janis Joplin and Jim Morrison. Nor is it limited to the rock-and-roll lifestyle—Thomas de Quincey invented the modern addiction memoir with his Confessions of an English Opium-Eater in 1821. In fact, the list of addicts often overlaps with the giants of culture. So is there a link between creativity and addiction? To find out, Scientific American spoke with neuroscientist David Linden of Johns Hopkins University School of Medicine and author of The Compass of Pleasure: How Our Brains Make Fatty Foods, Orgasm, Exercise, Marijuana, Generosity, Vodka, Learning and Gambling Feel So Good. Is there a link between creativity and addiction? No. I think the link is not between creativity and addiction per se. There is a link between addiction and things which are a prerequisite for creativity…. We know that 40 percent of a predisposition to addiction is genetically determined, via studies on heritability in families and twins. There's no single addiction gene. We don't even know all the genes involved in conferring addiction risk. But the ones we do know have to do with the signaling of the neurotransmitter dopamine for pleasure and reward. © 2011 Scientific American

Keyword: Drug Abuse
Link ID: 15616 - Posted: 07.28.2011

By Christof Koch Recently developed powerful, yet also delicate and refined, genetic tools can inva­sively probe nervous systems of animals, far surpassing the safer but much cruder techniques that psychologists and cognitive neuroscientists use to observe the human brain. Now in a remarkable series of experiments, researchers have located a trigger for aggression in mice—providing us with fresh insights into the workings of our human consciousness. You might object that mice and men are not the same and that studying the murine mind is different from studying the human mind. This fact is obviously true. Yet both Mus musculus and Homo sapiens are nature’s children, sharing much perceptual, cognitive and affective processing. The same process of relentless evolutionary selection has shaped both species—our last common ancestor was a mere 75 million years ago. The structure of their brains, and of their genomes, reflects this similarity. Indeed, only a neuroanatomist can tell a rice grain–size piece of mouse cortex from the same chunk of human cortex. If you think of a mouse as a mere automaton, Google “world’s smartest mouse.” The top hit will be a YouTube video of Brain Storm, a cute brown mouse running a complicated obstacle course—crossing an abyss on a rope; jumping through hoops; going up and down a seesaw, over a pencil, up a steep incline and down a ladder; and navigating around obstacles. It hesitates on occasion, sniffs the air but, once started, speedily completes the circuit. The amazing finesse and utility of contemporary molecular biology techniques are illustrated in recent experiments dealing with sex and power—the twin themes around which much of popular culture, psychoanalysis and art is centered. © 2011 Scientific American

Keyword: Aggression
Link ID: 15615 - Posted: 07.28.2011

by Sara Reardon The "singing" in this video may not be your idea of a pop masterpiece—indeed it may make you want to throw your speakers through the window—but to female mice the sounds are as sweet as the deep crooning of Frank Sinatra. In a new study, researchers captured approximately 100 singing mice, also known as Alston's Brown Mice (Scotinomys teguina) from Costa Rica, and implanted some of the males with extra male hormones while castrating the others. The hormonally enhanced males sang more rapidly and with a wider range of frequencies than the castrati—and females noticed the difference. When the researchers played the recordings for a female mouse through speakers on either end of her cage, she walked over to the speaker piping out the tunes of the pumped-up male and sat down in front of it, like a groupie at a concert. The female probably assumes that this male would make a better mate and father, the researchers report in the August issue of Animal Behavior, though you never know with pop stars. © 2010 American Association for the Advancement of Science

Keyword: Sexual Behavior; Animal Communication
Link ID: 15614 - Posted: 07.28.2011

by Virginia Morell Asian elephants have long been considered somewhat antisocial. Instead of living in large, tightly knit herds, as do female elephants on the African savanna, those in Asia were thought to have only small groups of friends and few outside connections. But a new study shows that many female Asian elephants are more like social butterflies, with numerous pals. And they're able to maintain strong friendships even with those they have not seen in a year or more. The study adds Asian elephants to a short list of other species, including dolphins, that are able to maintain complex social relationships despite not having daily contact, an ability regarded as being cognitively demanding. "People thought they knew what Asian elephants were doing [socially] based on what they saw them doing in captivity," says Shermin de Silva, a behavioral ecologist with the Elephant, Forest and Environment Conservation Trust in Colombo, Sri Lanka, and the lead author of the new study. Asian elephants are also extremely difficult to study in the wild, she adds. They inhabit dense forests, so researchers are usually able to observe the animals only by climbing tall trees or watching them when they gather at water holes. But 30 years ago, one population of Asian elephants on Sri Lanka became observable because it lost its forest home. People logged the trees, converted the land into teak plantations, and subsequently dammed the region's main river, creating the large Uda Walawe reservoir. In 1972, 308 square kilometers around the reservoir were made into the Udawalawe National Park. Some 800 to 1200 former forest elephants now live here on grass- and scrublands that resemble an East African savanna, de Silva says. © 2010 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 15613 - Posted: 07.28.2011