LONDON - Young people who smoke cannabis or marijuana for six years or more are twice as likely to have psychotic episodes, hallucinations or delusions than people who have never used the drug, scientists said on Monday. The findings adds weight to previous research which linked psychosis with the drug — particularly in its most potent form as "skunk" — and will feed the debate about the level of controls over its use. Despite laws against it, up to 190 million people around the world use cannabis, according to United Nations estimates, equating to about 4 percent of the adult population. John McGrath of the Queensland Brain Institute in Australia studied more than 3,801 men and women born between 1981 and 1984 and followed them up after 21 years to ask about their cannabis use and assessed them for psychotic episodes. Around 18 percent reported using cannabis for three or fewer years, 16 percent for four to five years and 14 percent for six or more years. For most of the study, researchers didn't measure the frequency of cannabis use among subjects, but rather whether they used at all. "Compared with those who had never used cannabis, young adults who had six or more years since first use of cannabis were twice as likely to develop a non-affective psychosis (such as schizophrenia)," McGrath wrote in a study published in the Archives of General Psychiatry journal. Copyright 2010 Reuters.

Keyword: Drug Abuse; Schizophrenia
Link ID: 13826 - Posted: 06.24.2010

By JOYCE COHEN For football fans, the indelible image of last month’s Super Bowl might have been quarterback Drew Brees’s fourth-quarter touchdown pass that put the New Orleans Saints ahead for good. But for audiologists around the nation, the highlight came after the game — when Mr. Brees, in a shower of confetti, held aloft his 1-year-old son, Baylen. The boy was wearing what looked like the headphones worn by his father’s coaches on the sideline, but they were actually low-cost, low-tech earmuffs meant to protect his hearing from the stadium’s roar. Specialists say such safeguards are critical for young ears in a deafening world. Hearing loss from exposure to loud noises is cumulative and irreversible; if such exposure starts in infancy, children can live “half their lives with hearing loss,” said Brian Fligor, director of diagnostic audiology at Children’s Hospital Boston. “This message needs to be conveyed to parents over and over again,” Dr. Fligor said. “If a child attends only one loud sporting event, it isn’t a big deal. But for those kids who will be going to football games throughout their lives, as Drew Brees’s kids will, it’s a very big deal. A young, tender ear may not be able to withstand damage.” According to the National Institute for Occupational Safety and Health, more than 15 minutes of exposure to 100 decibels is unsafe. The noise in a football stadium can reach 100 to 130 decibels. Copyright 2010 The New York Times Company

Keyword: Hearing
Link ID: 13825 - Posted: 06.24.2010

By TARA PARKER-POPE The basic formula for gaining and losing weight is well known: a pound of fat equals 3,500 calories. That simple equation has fueled the widely accepted notion that weight loss does not require daunting lifestyle changes but “small changes that add up,” as the first lady, Michelle Obama, put it last month in announcing a national plan to counter childhood obesity. In this view, cutting out or burning just 100 extra calories a day — by replacing soda with water, say, or walking to school — can lead to significant weight loss over time: a pound every 35 days, or more than 10 pounds a year. While it’s certainly a hopeful message, it’s also misleading. Numerous scientific studies show that small caloric changes have almost no long-term effect on weight. When we skip a cookie or exercise a little more, the body’s biological and behavioral adaptations kick in, significantly reducing the caloric benefits of our effort. But can small changes in diet and exercise at least keep children from gaining weight? While some obesity experts think so, mathematical models suggest otherwise. The first lady, Michelle Obama, spoke last month at the White House about her “Let’s Move” initiative, which aims to change the way children eat and play. Copyright 2010 The New York Times Company

Keyword: Obesity
Link ID: 13824 - Posted: 06.24.2010

By Tina Hesman Saey In the heavyweight division, immune cells embedded in fat pack some extra disease-causing punches, a new study shows. Those punches involve potentially dangerous proteins linked to inflammation, heart disease and diabetes. Something in the adipose tissue, or fat, of overweight people primes immune cells called macrophages nestled within the tissue to release the proteins when the cells sense high levels of fat in the bloodstream, researchers report in the Feb. 24 Science Translational Medicine. The discovery may lead to treatments that could block disease formation in overweight or obese people. Blood levels of free fatty acids, such as triglycerides, rise after a high-fat meal and, in obese people, are often constantly elevated to levels two to three times higher than normal, says Preeti Kishore, an endocrinologist at the Albert Einstein College of Medicine in New York City. In the new study, Kishore and her colleagues show that these types of fat particles prod immune cells called macrophages to make PAI-1, a protein linked to heart disease. The protein, whose full name is plasminogen activator inhibitor-1, keeps blood clots, which can cause strokes or heart attacks, from breaking up. The fatty acids also triggered the release of inflammation-causing proteins called TNF-alpha and IL-6, the researchers found. Inflammation caused by those and other proteins is thought to play a role in type 2 diabetes in obese people. © Society for Science & the Public 2000 - 2010

Keyword: Obesity; Neuroimmunology
Link ID: 13823 - Posted: 06.24.2010

by Richard L. Doty FOR more than 50 years, researchers - many of them prominent scientists - have assumed that single or small sets of innate biochemicals trigger behavioural and endocrine responses in mammals of the same species. These agents, never chemically identified, were labelled "pheromones". The term was borrowed from insect studies of the early 1930s, where it replaced "ectohormone" (external hormone) to describe the single biochemicals which trigger predictable responses in relatively simple organisms. It was not until the 1960s that the quest to find pheromones in mammals became a really big deal. In Science in 1962, endocrinologists Alan Parkes and Hilda Bruce wrote that "endocrinology has flowered magnificently in the last 40 years; exocrinology is now about to blossom". The father of sociobiology, E. O. Wilson, suggested the possibility that "pheromones are in a special sense the lineal ancestors of hormones" in a 1972 Scientific American article. Even Alex Comfort, author of the 1970s best-seller The Joy of Sex, argued in a Nature paper that pheromones were likely to exist in humans. Since then, a plethora of studies has implicated pheromones in many mammalian activities, including sex, maternal behaviour, fighting, nesting, and the recognition of members of one's own species. Pheromones have been said to accelerate the onset of puberty, block pregnancies and influence oestrous cycles and hormonal surges in a range of mammals, although no one has ever identified the agents involved. © Copyright Reed Business Information Ltd

Keyword: Chemical Senses (Smell & Taste)
Link ID: 13822 - Posted: 06.24.2010

By John Kelley Question: Are antidepressants effective or ineffective? Answer: Yes! In my view, both these statements are true: Antidepressants do work. And antidepressants don’t work. Not to put too fine a Clintonian point on it, but determining whether antidepressants work depends on the definition of the word “work.” A controversial article just published in the prestigious Journal of the American Medical Association concluded that antidepressants are no more effective than placebos for most depressed patients. Jay Fournier and his colleagues at the University of Pennsylvania aggregated individual patient data from six high-quality clinical trials and found that the superiority of antidepressants over placebo is clinically significant only for patients who are very severely depressed. For patients with mild, moderate, and even severe depression, placebos work nearly as well as antidepressants. There have been at least four other review articles published in the last eight years that have come to similar conclusions about the limited clinical efficacy of antidepressants, and one of the study authors, psychologist Irving Kirsch, has recently published a book on the topic, provocatively entitled The Emperor’s New Drugs: Exploding the Antidepressant Myth. The recent review articles questioning the clinical efficacy of antidepressants run counter to the received wisdom in the psychiatric community that antidepressants are highly effective. Indeed, it wasn’t so long ago that psychiatrist Peter Kramer wrote in his best-selling book Listening to Prozac that this miracle drug made patients “better than well.” Prozac was a Rock Star. Its extraordinary success even led to a photograph of the green and white capsule on the cover of Newsweek Magazine in 1990. © 2010 Scientific American,

Keyword: Depression
Link ID: 13821 - Posted: 06.24.2010

by Jennifer Couzin-Frankel In 1922, a Toronto teenager with diabetes became the first person to be saved by insulin treatment, and since then injections have sustained millions of diabetics, who don’t make their own hormone. But are there alternatives to a lifetime of insulin therapy? A new study suggests that an appetite-suppressing hormone called leptin is just as effective as insulin at controlling diabetes in mice. The discovery of insulin transformed type 1 diabetes from a fatal to a chronic disease. In this type of diabetes, the body destroys insulin-producing cells in the pancreas, resulting in high blood glucose levels. (The more common form of diabetes, type 2, occurs when the body doesn’t respond properly to its own insulin.) But insulin treatment isn’t perfect. Getting the dose of insulin just right is difficult, and despite their best efforts to manage their disease, many people with diabetes suffer severe complications, including kidney failure, blindness, and limb amputation. Diabetes researchers are considering various replacements for insulin injections: Transplanting new pancreatic islet cells that make insulin, coaxing the patient’s own islets to regenerate, or treating diabetics early in the disease with immune-suppressing therapies to prevent their body from destroying the rest of their pancreatic islets. Some studies have also considered leptin; like insulin, this hormone helps the body reduce glucose levels. Last year, researchers reported that mice with a form of diabetes recovered after receiving leptin gene therapy directly into the brain. © 2010 American Association for the Advancement of Science.

Keyword: Obesity; Hormones & Behavior
Link ID: 13820 - Posted: 06.24.2010

By PAULINE W. CHEN, M.D. The patient was already on the operating room table when the other transplant surgeons and I arrived to begin the surgery that would remove his liver, kidneys, pancreas, lungs and heart. He was tall, with legs that extended to the very end of the table, a chest barely wider than his 16-year-old hips, and a chin covered with pimples and peach fuzz. He looked like any one of the boys I knew in high school. Those of us in the room that night knew his organs would be perfect — he had been a healthy teenager before death — but the fact that he had not died in a terrible, mutilating automobile or motorcycle crash made us all that much more certain. The boy had hanged himself and had been discovered early, though not early enough to have survived. While I had operated on more than a few suicide victims, I had never come across someone so young who had chosen to die in this way. I asked one of the nurses who had spent time with the family about the circumstances of his death. Was he depressed? Had anyone ever suspected? Who found him? “He was playing the choking game,” she said quietly. I stopped what I was doing and, not believing I had heard correctly, turned to look straight at her. “You know that game where kids try to get high,” she explained. “They strangle themselves until just before they lose consciousness.” She put her hand on the boy’s arm then continued: “Problem was that this poor kid couldn’t wiggle out of the noose he had made for himself. His parents found him hanging by his belt on his bedroom doorknob.” Copyright 2010 The New York Times Company

Keyword: Drug Abuse
Link ID: 13819 - Posted: 06.24.2010

by Carla K. Johnson, Associated Press One in four U.S. parents believes some vaccines cause autism in healthy children, but even many of those worried about vaccine risks think their children should be vaccinated. Most parents continue to follow the advice of their children's doctors, according to a study based on a survey of 1,552 parents. Extensive research has found no connection between autism and vaccines. "Nine out of 10 parents believe that vaccination is a good way to prevent diseases for their children," said lead author Dr. Gary Freed of the University of Michigan. "Luckily their concerns don't outweigh their decision to get vaccines so their children can be protected from life-threatening illnesses." In 2008, unvaccinated school-age children contributed to measles outbreaks in California, Illinois, Washington, Arizona and New York, said Dr. Melinda Wharton of the U.S. Centers for Disease Control and Prevention. Thirteen percent of the 140 who got sick that year were hospitalized. "It's fortunate that everybody recovered," Wharton said, noting that measles can be deadly. "If we don't vaccinate, these diseases will come back." Fear of a vaccine-autism connection stems from a flawed and speculative 1998 study that recently was retracted by a British medical journal. The retraction came after a council that regulates Britain's doctors ruled the study's author acted dishonestly and unethically. © 2010 Discovery Communications, LLC.

Keyword: Autism
Link ID: 13818 - Posted: 06.24.2010

By Stephanie Pappas Sleep is supposed to be a time of peace and relaxation. Most of us drift from our waking lives into predictable cycles of deep, non-rapid-eye-movement sleep, followed by dream-filled rapid-eye-movement (REM) sleep. But when the boundaries of these three phases of arousal get fuzzy, sleep can be downright scary. In fact, some sleep disorders seem more at home in horror films than in your bedroom. Whether it's running from axe-wielding murderers or showing up naked in the school cafeteria, most of us have been jolted awake by a nightmare at some point. When nightmares move beyond occasional annoyance to near-nightly terror, however, you might have nightmare disorder. People with nightmare disorder often wake in a cold sweat with vivid memories of horrible dreams. Their waking life suffers. They may dread sleep. Stress and sleep deprivation are major nightmare triggers, as are some medications, according to the American Sleep Association (ASA). In severe cases, counseling or sedative drugs might be necessary to soothe the anxiety underlying the bad dreams. For most of us, though, banishing the nighttime axe-murderer is as easy as taking a relaxing bath and going to bed on time. Up to 15 percent of adults occasionally get up and amble around the house in their sleep. In children, the number is even higher. No one knows what makes some sleepers wander, but stress and disturbed sleep are often factors. So is genetics: Close relatives of sleepwalkers are 10 times more likely to sleepwalk than the general population. © 2010 LiveScience.com.

Keyword: Sleep
Link ID: 13817 - Posted: 06.24.2010

Andrew Bennett Hellman The body's internal clock helps to regulate a water-storing hormone so that nightly dehydration or trips to the toilet are not the norm, research suggests. In an article published in Nature Neuroscience today, neurophysiologists Eric Trudel and Charles Bourque at the Research Institute of the McGill University Health Centre in Montreal, Canada, propose a mechanism by which the body's circadian system, or internal clock, controls water regulation1. By allowing cells that sense water levels to activate cells that release vasopressin, a hormone that instructs the body to store water, the circadian system keeps the body hydrated during sleep. "We've known for years that there's a rhythm of vasopressin that gets high when you're sleeping. But no one knew how that occurred. And this group identified a very concrete physiological mechanism of how it occurs," says Christopher Colwell, a neuroscientist who studies sleep and circadian rhythms at the David Geffen School of Medicine at the University of California, Los Angeles. The body regulates its water content mainly by balancing water intake through thirst with water loss through urine production. People don't drink during sleep, so the body has to minimize water loss to remain sufficiently hydrated. Scientists knew that low water levels excite a group of cells called osmosensory neurons, which direct another set of neurons to release vasopressin into the bloodstream. Vasopressin levels increase during sleep; clock neurons, meanwhile, get quieter. © 2010 Nature Publishing Group,

Keyword: Biological Rhythms; Hormones & Behavior
Link ID: 13816 - Posted: 06.24.2010

By Karen Weintraub Ana can sit on the couch for only about five minutes before it’s time to move. First she rides her bright blue unicycle a few times around the dining room table. Then she gets on a swing hung from the doorway and pumps until her feet can touch the ceiling. A few minutes later she’s doing laps around the table on her RipStik - a skateboard-like balance board. Then she runs outside and climbs the back fence (more fun than going through the gate), to jump on a trampoline. After mastering a flip, she manages to climb back into the house through an open window. Life with Ana, who turns 11 this month, is action-packed. The fifth-grader has sensory processing disorder - her brain doesn’t process information from her five senses in a typical way - leaving her unable to sit still (her muscles just have to move), wear socks (they’re too irritating), concentrate in a busy classroom (so much to look at and hear), or be in the same room with a hot pizza (the aroma is overpowering). “You know when you wake up in the morning, if you don’t have your coffee and your car doesn’t work and you get to the office and someone’s given you a new project that’s due today instead of tomorrow - that’s what it’s like for these kids every day,’’ her mother, Pauline Pimlott, said. Getting help for such kids can be tough. Insurance often won’t pick up the tab, because sensory processing disorder isn’t officially recognized by the American Psychiatric Association, which writes the definitive manual on disabilities such as autism, dyslexia, and attention-deficit hyperactivity disorder. Ana has received specialized occupational therapy on and off for years, but at $175 an hour, it’s too expensive to do often, her mother says. © 2010 NY Times Co.

Keyword: Pain & Touch; Development of the Brain
Link ID: 13815 - Posted: 06.24.2010

By Manfred Dworschak Neurologists are employing brain electrodes to try to establish contact with people in vegetative and minimally conscious states. This could be the last hope for Belgian Rom Houben, who has been trapped in his own body for 23 years. Attempts to let him communicate by means of a keyboard have failed. Day after day, Marie-Aurélie Bruno attaches caps wired with embedded electrodes to her patients' shaved heads. The neuropsychologist at the University of Liège in Belgium is looking for signals in the quivering readouts of the brain's electrical activity, where there might be a hidden message. Bruno's patients are in a condition marked by both a "vegetative state" (VS) and a "minimally conscious state" (MCS). Most of the time, they seem completely withdrawn from the world, though their eyes remain open. Only occasionally does a blink of the eye or a squeeze of the hand reveal that some of these patients retain a small amount of consciousness. Listening in on their brains directly could allow better access to them. "In some individual cases, we might even be able to establish a channel of communication," says Steven Laureys, director of the research group in Liège. The technique the group is using has its origins in the laboratory of Niels Birbaumer, a neurologist at the University of Tübingen in southwestern Germany. "It has worked out pretty well for us," he says of the treatment he uses on patients with "locked-in syndrome" -- that is, ones who are verifiably fully conscious but paralyzed from head to foot. With the help of electrodes, some patients are able to communicate via a computer. A variety of letters appear on the screen in quick succession. By briefly concentrating on the word "yes," the test subjects can indicate the desired letter. Sometimes they manage this within a few seconds; sometimes it takes a full minute. © DER SPIEGEL 7/2010

Keyword: Attention; Language
Link ID: 13814 - Posted: 06.24.2010

By JONAH LEHRER The Victorians had many names for depression, and Charles Darwin used them all. There were his “fits” brought on by “excitements,” “flurries” leading to an “uncomfortable palpitation of the heart” and “air fatigues” that triggered his “head symptoms.” In one particularly pitiful letter, written to a specialist in “psychological medicine,” he confessed to “extreme spasmodic daily and nightly flatulence” and “hysterical crying” whenever Emma, his devoted wife, left him alone. While there has been endless speculation about Darwin’s mysterious ailment — his symptoms have been attributed to everything from lactose intolerance to Chagas disease — Darwin himself was most troubled by his recurring mental problems. His depression left him “not able to do anything one day out of three,” choking on his “bitter mortification.” He despaired of the weakness of mind that ran in his family. “The ‘race is for the strong,’ ” Darwin wrote. “I shall probably do little more but be content to admire the strides others made in Science.” Darwin, of course, was wrong; his recurring fits didn’t prevent him from succeeding in science. Instead, the pain may actually have accelerated the pace of his research, allowing him to withdraw from the world and concentrate entirely on his work. His letters are filled with references to the salvation of study, which allowed him to temporarily escape his gloomy moods. “Work is the only thing which makes life endurable to me,” Darwin wrote and later remarked that it was his “sole enjoyment in life.” Copyright 2010 The New York Times Company

Keyword: Depression; Evolution
Link ID: 13813 - Posted: 06.24.2010

By RONI CARYN RABIN Surgery on blocked neck arteries has long been considered the best procedure for preventing a stroke. Now a large North American study has found that a less invasive approach may be just as safe and effective, but other researchers are not so sure. The findings, released Friday at a medical meeting in San Antonio, have the potential to make the less invasive procedure — inserting a small tube called a stent in the carotid artery — a more appealing option for many patients. Yet just a day earlier, European investigators reported dismal results from another international trial involving carotid stents, published online Thursday by the British medical journal The Lancet. In that study, patients treated with stents suffered almost double the rate of complications as those treated surgically, leading the British researchers to conclude that surgical treatment of carotid blockages, called endarterectomy, remains the treatment of choice. The disparate findings — which could help determine whether Medicare expands coverage to cover the stent procedure — left scientists trying to explain why two fairly similar clinical trials came to such starkly different conclusions. Copyright 2010 The New York Times Company

Keyword: Stroke
Link ID: 13812 - Posted: 06.24.2010

DYING ear cells have been revived with a shot of gene therapy. Ear cells have a hair-like structure that enables them to pick up sound vibrations. They are vital for hearing in mammals but are easily damaged by loud noise, which can lead to deafness. A gene called Math1 has already been used to generate new hair cells in guinea pigs, from the supporting cells that surround them. Now David He at Creighton University in Omaha, Nebraska, and colleagues have shown that the same gene can repair guinea pigs' existing, damaged hair cells - as long as you get to them in time. He's team exposed guinea pigs to the audio equivalent of 200 rounds of gunfire. After this, the animals couldn't hear anything quieter than a chainsaw. When the researchers injected the animals with a Math1-loaded virus in one ear, hearing recovered almost completely. The team tested the guinea pigs' hearing by monitoring the electrical activity in their brainstems in response to various noises. Then they viewed the newly grown cells in samples under a microscope. The hair cells also expressed a green protein, showing they had taken up the gene. Although the gene is only temporarily expressed, this is enough to make proteins that repair the cells for life, he says. However, cells could only be saved if they were treated within 10 days of being damaged. He presented the work at the Association for Research in Otolaryngology meeting in Anaheim, California. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Regeneration
Link ID: 13811 - Posted: 06.24.2010

Athletes who wear red could have a subtle advantage, say Canadian researchers, who have found that the eye perceives red as moving faster than other colours. Mazyar Fallah, a professor of kinesiology and health science at York University, says wearing red might confer a slight advantage in sports such as figure-skating and gymnastics, where judging is involved. Fallah points to International Skating Union rules, which include a base score for each element. "These are based on criteria, which include speed on the ice," Fallah told CBC Radio's Quirks & Quarks. "So, if you're wearing red instead of blue doing exactly the same routine, then [the judges'] eyes move a little faster. "And maybe that subconscious effect … will actually cause them to bump you up one point more than they would if you were wearing blue." Fallah said the experiment, conducted with Illia Tchernikov at York's Centre for Vision Research, doesn't show that red skating costumes result in higher scores, only that the eye moves faster when tracking red objects. "We don't know for certain that this is actually happening … but if it were me, I'd wear red every time," he said. In the experiment, published this week in the journal PLoS One, five participants took part in thousands of tests where they watched coloured dots moving on a computer screen. © CBC 2010

Keyword: Vision
Link ID: 13810 - Posted: 06.24.2010

By Nathan Seppa SAN ANTONIO — As many as four in 10 people referred to a clinic with signs of a “ministroke” may have subtle cognitive damage that standard tests miss, a new study shows. The findings, reported by Canadian researchers February 24 at the International Stroke Conference in San Antonio, Texas, suggest that after suffering the ministrokes many patients lose some ability to process abstract thoughts, reason things out and make quick calculations — what doctors call “executive function.” While full-blown strokes cause a clear loss of cognitive function, most often due to a blood vessel blockage in the brain that shows up on an MRI or CT scan, ministrokes are caused by smaller obstructions. They result in more subtle deficits that are less likely to be detected by brain scans or even by patients themselves. Some scientists consider the term ministroke a misnomer, preferring the technical term transient ischemic attack, while others use the terms interchangeably. The symptoms of a ministroke or a full-blown one might start out the same, with numbness in the face or extremities, confusion, vision problems, dizziness or headache. But in a ministroke, these symptoms wane after minutes or hours. In the new study, researchers tested 140 such patients in whom symptoms subsided within 24 hours, indicating they had ministrokes instead of full-blown ones. They gave the subjects a test of cognitive acuity that is routinely given to patients who show up at a clinic or hospital with signs of a stroke. Known as the Mini-Mental Status Exam, the test quickly gauges 30 cognitive functions including short-term recall, attention span, spatial recognition and executive function. © Society for Science & the Public 2000 - 2010

Keyword: Stroke
Link ID: 13809 - Posted: 06.24.2010

By Katie Moisse The same technology that has people swinging imaginary rackets and bowling virtual balls for entertainment at home might help people recovering from strokes, according to research presented February 25 at the American Stroke Association's International Stroke Conference. The pilot study, carried out at the Toronto Rehabilitation Institute at the University of Toronto, suggests that video games for the Nintendo Wii could help stroke victims regain lost motor function. "This is the first randomized clinical study showing that virtual reality using Wii gaming technology is feasible and safe and is potentially effective in enhancing motor function following a stroke,” said the study’s lead investigator, Gustavo Saposnik, in a prepared statement. “But our study results need to be confirmed in a major clinical trial.” The study examined the Wii’s potential for helping patients recover fine motor function (such as finger dexterity) and gross motor function (such as arm movements) two months after a stroke. Twenty patients were randomly assigned to two groups: one played recreational games (such as cards or the block-stacking game Jenga); the other played virtual games such as Wii tennis and Wii Cooking Mama—a simulation game that has players cutting potatoes, peeling onions and shredding cheese. Both groups played for about six hours over the course of the two-week study. © 2010 Scientific American, a division of Nature America

Keyword: Stroke
Link ID: 13808 - Posted: 06.24.2010

By Jennifer Viegas Experts say that a fatal killer whale attack at SeaWorld in Orlando may have been tied to the isolation and breeding of the male marine mammal. Tilikum, the male killer whale that fatally injured trainer Dawn Brancheau in front of a stunned audience at SeaWorld in Orlando on Wednesday, was a breeding "stud" often housed in isolation. Experts believe he did not kill for food, but may have been acting out due to stress and raging hormones. While some reports have been portraying Tilikum as a particularly aggressive orca, a nearly identical incident involving another killer whale male named Ky occurred in July 2004 at the San Antonio SeaWorld. Trainer Steve Aibel, like Brancheau, was pulled underwater by the whale, which also attempted to bite, but Aibel walked away uninjured. He later blamed Ky's "adolescent hormones" for the episode. Marine biologist Nancy Blake told Discovery News that Tilikum could have acted out for similar reasons. "He was used a lot [by SeaWorld] for mating, and could have even been enacting a mating behavior during the incident," explained Blake, a leading expert on killer whales who runs California's Monterey Bay Whale Watch. © 2010 Discovery Communications, LLC.

Keyword: Aggression; Sexual Behavior
Link ID: 13807 - Posted: 06.24.2010