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Ian Sample Science editor Tiny biological compasses made from clumps of protein may help scores of animals, and potentially even humans, to find their way around, researchers say. Scientists discovered the minuscule magnetic field sensors in fruit flies, but found that the same protein structures appeared in retinal cells in pigeons’ eyes. They can also form in butterfly, rat, whale and human cells. The rod-like compasses align themselves with Earth’s geomagnetic field lines, leading researchers to propose that when they move, they act on neighbouring cell structures that feed information into the nervous system to create a broader direction-sensing system. Professor Can Xie, who led the work at Peking University, said the compass might serve as a “universal mechanism for animal magnetoreception,” referring to the ability of a range of animals from butterflies and lobsters to bats and birds, to navigate with help from Earth’s magnetic field. Whether the compasses have any bearing on human navigation is unknown, but the Peking team is investigating the possibility. “Human sense of direction is complicated,” said Xie. “However, I believe that magnetic sense plays a key role in explaining why some people have a good sense of direction.” The idea that animals could sense Earth’s magnetic field was once widely dismissed, but the ability is now well established, at least among some species. The greatest mystery that remains is how the sensing is done. © 2015 Guardian News and Media Limited

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21638 - Posted: 11.17.2015

David Cyranoski A Chinese neuroscientist has been sacked after reporting he had used magnetic fields to control neurons and muscle cells in nematode worms (pictured), using a protein that senses magnetism. Tsinghua University in Beijing has sacked a neuroscientist embroiled in a dispute over work on a long-sought protein that can sense magnetic fields. The university has not given a specific reason for its dismissal, however, and the scientist involved, Zhang Sheng-jia, says that he will contest their action. In September, Zhang reported in the journal Science Bulletin1 that he could manipulate neurons in worms by applying a magnetic field — a process that uses a magnetic-sensing protein. But a biophysicist at neighbouring Peking University, Xie Can, who claims to have discovered the protein’s magnetic-sensing capacity and to have a paper detailing his research under review, complained that Zhang should not have published his paper before Xie’s own work appeared. Xie said that by publishing, Zhang violated an agreement that the pair had reached — although the two scientists tell different versions about the terms of their agreement, and have different explanations of how Zhang came to be working with the protein. © 2015 Nature Publishing Group

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21608 - Posted: 11.06.2015

By Christopher Intagliata If you're lost, you need a map and a compass. The map pinpoints where you are, and the compass orients you in the right direction. Migratory birds, on the other hand, can traverse entire hemispheres and end up just a couple miles from where they bred last year, using their senses alone. Their compass is the Sun, the stars and the Earth's magnetic field. But their map is a little more mysterious. One theory goes that they use olfactory cues—how a place smells. Another is that they rely on their sense of magnetism. Researchers in Russia investigated the map issue in a past study by capturing Eurasian reed warblers on the Baltic Sea as they flew northeast towards their breeding grounds near Saint Petersburg. They moved the birds 600 miles east, near Moscow. And the birds just reoriented themselves to the northwest—correctly determining their new position. Now the same scientists have repeated that experiment—only this time, they didn't move the birds at all. They just put them in cages that simulated the magnetic field of Moscow, while still allowing the birds to experience the sun, stars and smells of the Baltic. Once again, the birds re-oriented themselves to the northwest—suggesting that the magnetic field alone—regardless of smells or other cues, is enough to alter the birds' mental map. The study is in the journal Current Biology. [Dmitry Kishkinev et al, Eurasian reed warblers compensate for virtual magnetic displacement] And if you're envious of that sixth sense—keep in mind that since the Earth's magnetic field fluctuates, the researchers say magnetic route-finding is best for crude navigation. Meaning for door-to-door directions—you’re still better off with your GPS. © 2015 Scientific American,

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21508 - Posted: 10.14.2015

By Virginia Morell How homing pigeons find their way home has long mystified scientists. Experiments have shown they rely on smells to create a mental map of their route and on the sun or Earth’s magnetic fields to navigate. But they also use vision, memorizing roads, railway lines, and rivers. To understand just how important pigeons’ visual memories are for homing, scientists trained 12 birds to fly to their home lofts while wearing patches covering one eye (as in the photo above). Each bird wore a GPS logging device and made 18 flights with the left or right eye blocked, followed by another 18 trips with the opposite eye covered. Unlike mammals, birds lack a key neural structure—the corpus callosum—that allows both hemispheres of the brain to access what an animal sees. The experiments revealed that this missing neural structure affects the pigeons’ homing abilities, the scientists report in today’s the Proceedings of the Royal Society B. Pigeons that learned their way home with a blocked left eye couldn’t repeat the same journey when they wore a patch over their right eye, and vice versa. Instead, they flew slightly off course, following more of a curve than a straight line. The new work proves that vision, too, plays a key role in how pigeons find their way home. © 2015 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 21481 - Posted: 10.07.2015

David Cyranoski A dispute has broken out at two of China’s most prestigious universities over a potentially groundbreaking discovery: the identification of a protein that may allow organisms to sense magnetic fields. On 14 September, Zhang Sheng-jia, a neuroscientist at Tsinghua University in Beijing, and his colleagues published a paper1 in Science Bulletin claiming to use magnetic fields to remotely control neurons and muscle cells in worms, by employing a particular magnetism-sensing protein. But Xie Can, a biophysicist at neighbouring Peking University, says that Zhang’s publication draws on a discovery made in his laboratory, currently under review for publication, and violates a collaboration agreement the two had reached. Administrators at Tsinghua and Peking universities, siding with Xie, have jointly requested that the journal retract Zhang’s paper, and Tsinghua has launched an investigation into Zhang’s actions. The dispute revolves around an answer to the mystery of how organisms as diverse as worms, butterflies, sea turtles and wolves are capable of sensing Earth’s magnetic field to help them navigate. Researchers have postulated that structures in biological cells must be responsible, and dubbed these structures magnetoreceptors. But they have never been found. In research starting in 2009, Xie says that he used a painstaking whole-genome screen to identify a protein containing iron and sulfur that seems, according to his experiments, to have the properties of a magnetoreceptor. He called it MagR, to note its purported properties, and has since been examining its function and structure to determine how it senses magnetic fields. © 2015 Nature Publishing Group,

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21431 - Posted: 09.22.2015

By Annick Laurent Can you tell a pygmy blue whale from an Antarctic blue whale? If not, you aren’t alone. Marine biologists have had trouble distinguishing these enormous mammals with mottled skin patterns ever since they began studying them—and that has complicated efforts to figure out where they breed and how to best protect them. Now, researchers have caught a break thanks to a pygmy whale named Isabela. Researchers first photographed the whale and collected her DNA in 1998 in the waters off the Galapagos Islands. Then, in 2006, another team photographed and collected samples from a similar looking whale off Chile (both photos above). Now, in a study published online before print in Marine Mammal Science, scientists compared those samples and photographs, and discovered that they both belonged to the same whale. That means Isabela (named after the lead author’s daughter to represent hope for future preservation efforts) migrated a minimum of 5200 km, the longest recorded latitudinal migration made by any Southern Hemisphere blue whale on record. The findings suggest Chile's and the Galapagos’ blue whale aggregations are connected, meaning those feeding in the Gulf of Corcovado off Chile may be breeding in the Tropical Eastern Pacific. Knowing where this species migrates—including its feeding and breeding grounds—can help conservationists and governments better establish marine protected areas, the team says. © 2015 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21213 - Posted: 07.25.2015

By JAMES GORMAN Call it the case of the homing lizards. It’s a small mystery. No one of any species is murdered. But the central question is one that has prompted plenty of scientific research: How do animals find their way home? The lizards in this case are anoles — abundant, mostly small reptiles that thrive in the Caribbean. The species is Anolis gundlachi. The lead detective is Manuel Leal, a biologist at the University of Missouri. He has been studying the behavior of anoles for more than 20 years. For about three years, Dr. Leal has been trying to understand how the anole finds its way back to its own territory after being carried into the rain forest. And as he told an audience in June at the annual meeting of the Animal Behavior Society in Anchorage, the case is far from closed. First, a bit of background. Anoles are particularly abundant in the dense vegetation of the rain forests in Puerto Rico, where Dr. Leal studies them. Each species is tied to a very specific environment. For instance, many live on tree trunks, but only a particular part of the trunk. Trunk-ground anoles live only in the space from the ground up to six feet or so. Trunk-crown anoles live above them, up to the crown of the tree. Twig anoles live way up high. Several years ago, Dr. Leal was studying competition between two species. If he removed all of the trunk-ground anoles, he wondered, would the trunk-crown lizards extend their territory farther down the tree? He ran into a problem, however. He would take the trunk-ground lizards far from their home territory to make room for their upstairs neighbors, and then release them. But in a reptilian version of the children’s song, “The Cat Came Back,” the lizards wouldn’t stay away. “Lizards kept showing up in the territory that had just been scoured for lizards,” he said. Dr. Leal wondered whether new anoles were appearing in empty territory or the old ones were returning. But how could a lizard that had never left home find its way back through 25 yards or so of dense rain forest? © 2015 The New York Times Company

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 21141 - Posted: 07.07.2015

By Will Dunham WASHINGTON (Reuters) - You might want to be careful about who you call a birdbrain. Some of our feathered friends exhibit powers of perception that put humans to shame. Scientists said on Thursday that little songbirds known as golden-winged warblers fled their nesting grounds in Tennessee up to two days before the arrival of a fierce storm system that unleashed 84 tornadoes in southern U.S. states in April. The researchers said the birds were apparently alerted to the danger by sounds at frequencies below the range of human hearing. The storm killed 35 people, wrecked many homes, toppled trees and tossed vehicles around like toys, but the warblers were already long gone, flying up to 930 miles (1,500 km) to avoid the storm and reaching points as far away as Florida and Cuba, the researchers said. Local weather conditions were normal when the birds took flight from their breeding ground in the Cumberland Mountains of eastern Tennessee, with no significant changes in factors like barometric pressure, temperature or wind speeds. And the storm, already spawning tornadoes, was still hundreds of miles away. "This suggests that these birds can detect severe weather at great distances," said wildlife biologist David Andersen of the U.S. Geological Survey and the University of Minnesota, one of the researchers in the study published in the journal Current Biology. "We hypothesize that the birds were detecting infrasound from tornadoes that were already occurring when the storm was still quite distant from our study site," Andersen added.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20433 - Posted: 12.20.2014

By Smitha Mundasad Health reporter, BBC News The precise part of the brain that gives people a sense of direction has been pinpointed by scientists. People with stronger nerve signals in their "internal compass" tended to be better navigators. The study, published in the journal Current Biology, suggested people get lost when their compass cannot keep up. The researchers in London hope the discovery will help explain why direction sense can deteriorate in conditions such as Alzheimer's disease. Scientists have long believed that such a signal existed within the brain, but until now it had been pure speculation. Volunteers were asked to navigate through a virtual environment Volunteers were asked to navigate towards certain objects placed in four corners of the virtual room They were then asked to navigate the area, from memory alone, while their brains were being scanned by an MRI machine. The scans revealed a part of the brain - known as the entorhinal region - fired up consistently during the tasks. The stronger the signal in the region, the better the volunteers were at finding their way around correctly. Dr Hugo Spiers, who led the study, said: "Studies on London cab drivers have shown that the first thing they do when they work out a route is calculate which direction they need to head in. "We now know the entorhinal cortex is responsible for such calculations and the quality of the signals from this region seem to determine how good someone's navigational skills will be." Dr Martin Chadwick, who was also involved in the study, explained: "Our results provide evidence to support the idea that your internal compass readjusts as you move through the environment. BBC © 2014

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 20431 - Posted: 12.20.2014

|By Tanya Lewis and LiveScience Dolphins can now add magnetic sense to their already impressive resume of abilities, new research suggests. When researchers presented the brainy cetaceans with magnetized or unmagnetized objects, the dolphins swam more quickly toward the magnets, the new study found. The animals may use their magnetic sense to navigate based on the Earth's magnetic field, the researchers said. A number of different animals are thought to possess this magnetic sense, called "magnetoreception," including turtles, pigeons, rodents, insects, bats and even deer (which are related to dolphins), said Dorothee Kremers, an animal behavior expert at the University of Rennes, in France, and co-author of the study published today (Sept. 29) in the journal Naturwissenschaften. "Inside the ocean, the magnetic field would be a very good cue to navigate," Kremers told Live Science. "It seems quite plausible for dolphins to have a magnetic sense." Some evidence suggests both dolphin and whale migration routes and offshore live strandings may be related to the Earth's magnetic field, but very little research has investigated whether these animals have a magnetic sense. Kremers and her colleagues found just one study that looked at how dolphins reacted to magnetic fields in a pool; that study found dolphins didn't show any response to the magnetic field. But the animals in that study weren't free to move around, and were trained to give certain responses. © 2014 Scientific American

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 20140 - Posted: 10.01.2014

By Jennifer Balmer Each summer, leatherback sea turtles (Dermochelys coriacea) migrate thousands of kilometers from their tropical breeding grounds to feed in cooler waters. Yet how the animals know when to begin their long journey back south at the end of the season has mostly remained a mystery. New findings, to be published in an upcoming issue of the Journal of Experimental Marine Biology and Ecology, suggest that leatherback sea turtles may be able to sense seasonal changes in sunlight by means of an unpigmented spot on the crown of their head—known as the pink spot (pictured). Researchers conducted an examination of the anatomical structures beneath the pink spot and found that the layers of bone and cartilage were remarkably thinner than in other areas of the skull. This thin region of the skull allows the passage of light through to an area of the brain, called the pineal gland, that acts as biological clock, regulating night-day cycles and seasonal patterns of behavior. The authors suggest that the lack of pigment in the crowning pink spot and thin skull region underlying it act as a “skylight,” allowing the turtles to sense the subtle changes in sunlight that accompany changing seasons, signaling them to return south when autumn approaches. © 2014 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 5: Hormones and the Brain; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 8: Hormones and Sex; Chapter 10: Biological Rhythms and Sleep
Link ID: 20069 - Posted: 09.13.2014

James Gorman All moving animals do their best to avoid running into things. And most living things follow a tried and true strategy — Watch where you’re going! Flying and swimming animals both have to cope with some complications that walkers, jumpers and gallopers don’t confront. Not only do they have to navigate in three dimensions, but they also cope with varying air and water flow. Beyond that, they often do so without the same references points and landmarks we have on the ground. Christine Scholtyssek of Lund University in Sweden, and colleagues decided to compare how two species in different mediums, air and water, which pose similar problems, reacted to apparent obstacles as they were moving. What they found, and reported in Biology Letters in May, was that the two species they examined — bumblebees and zebra fish — have very different strategies. It was known that the bees’ navigation depended on optic flow, which is something like the sensation of watching telephone poles speed past from a seat on a moving train. They tend to fly away from apparent obstacles as they approach them. The question was whether fish would do something similar. So, in order to give both animals the same test, Dr. Scholtyssek and her colleagues devised an apparatus that could contain air or water. When one wall had vertical stripes and the other horizontal, the bees, not surprisingly, flew away from the vertical stripes, which would have appeared as one emerging obstacle after another as the bees flew past. Horizontal stripes don’t change as a creature moves past, so they provide no reference for speed or progress. The fish, however, swam closer to the vertical stripes, which wasn’t expected. “It is surprising that although fish and bees have the same challenge, moving with or against streams, they do not use the same mechanisms,” Dr. Scholtyssek said. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 19778 - Posted: 07.01.2014

Jessica Morrison Bees, like birds and butterflies, use the Sun as a compass for navigation, whereas mammals typically find their way by remembering familiar landmarks on a continuous mental map. However, the latest research suggests that bees also use this type of map, despite their much smaller brain size. The work adds a new dimension to complex bee-navigation abilities that have long captivated researchers. “The surprise comes for many people that such a tiny little brain is able to form such a rich memory described as a cognitive map,” says co-author Randolf Menzel, a neurobiologist at the Free University of Berlin. The research by Menzel and his team, published today in the Proceedings of the National Academy of Sciences1, demonstrates that bees can find their way back to their hives without relying solely on the Sun. Instead, they seem to use a 'cognitive map' that is made up of memorized landscape snapshots that direct them home. The cognitive map used by mammals is thought to originate in the brain’s hippocampus. Humans employ such maps on a daily basis; for example, even in a windowless office, many people can point towards their home, orienting themselves in space based on knowledge of their location relative to the outside world. “They can point to their home generally even though they can’t see it, even along a path through a wall that they haven’t travelled,” explains Fred Dyer, a behavioural biologist at Michigan State University in East Lansing, who was not involved in the research. The study authors argue that bees can do something similar, albeit on a much more rudimentary level. © 2014 Nature Publishing Group

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 13: Memory, Learning, and Development
Link ID: 19684 - Posted: 06.03.2014

Jessica Morrison Interference from electronics and AM radio signals can disrupt the internal magnetic compasses of migratory birds, researchers report today in Nature1. The work raises the possibility that cities have significant effects on bird migration patterns. Decades of experiments have shown that migratory birds can orient themselves on migration paths using internal compasses guided by Earth's magnetic field. But until now, there has been little evidence that electromagnetic radiation created by humans affects the process. Like most biologists studying magnetoreception, report co-author Henrik Mouritsen used to work at rural field sites far from cities teeming with electromagnetic noise. But in 2002, he moved to the University of Oldenburg, in a German city of around 160,000 people. As part of work to identify the part of the brain in which compass information is processed, he kept migratory European robins (Erithacus rubecula) inside wooden huts — a standard procedure that allows researchers to investigate magnetic navigation while being sure that the birds are not getting cues from the Sun or stars. But he found that on the city campus, the birds could not orient themselves in their proper migratory direction. “I tried all kinds of stuff to make it work, and I couldn’t make it work,” Mouritsen says, “until one day we screened the wooden hut with aluminium.” Mouritsen and his colleagues covered the huts with aluminium plates and electrically grounded them to cut out electromagnetic noise in frequencies ranging from 50 kilohertz to 5 megahertz — which includes the range used for AM radio transmissions. The shielding reduced the intensity of the noise by about two orders of magnitude. Under those conditions, the birds were able to orient themselves. © 2014 Nature Publishing Group,

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 19590 - Posted: 05.08.2014

by Andy Coghlan Burmese pythons can find their way home even if they are taken dozens of kilometres away. It is the first demonstration that big snakes can navigate at all, and far exceeds the distances known to have been travelled by any other snake. At over 3 metres long, Burmese pythons (Python molurus bivitattus) are among the world's largest snakes. For the last two decades they have been eating their way through native species of Florida's Everglades National Park, having been abandoned to the wild by former owners. "Adult Burmese pythons were able to navigate back to their capture locations after having been displaced by between 21 and 36 kilometres," says Shannon Pittman of Davidson College in North Carolina. Pittman and her colleagues caught 12 pythons and fitted them with radiofrequency tags (see video). She released half of them where they were caught, as controls, and transported the other six to distant locations before releasing them. Five pythons made it back to within 5 kilometres of their capture location, and the sixth at least moved in the right direction. The displaced snakes made progress towards their destination most days and seldom strayed more than 22 degrees from the correct path. They kept this up for 94 to 296 days. By contrast, the control snakes moved randomly. On average, displaced snakes travelled 300 metres each day, while control snakes averaged just 100 metres per day. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 19380 - Posted: 03.19.2014

By Veronique Greenwood Young animals are capable of some pretty astounding feats of navigation. To a species like ours, whose native sense of direction isn’t much to speak of—have you ever seen a human baby crawl five thousand miles home?—the intercontinental odysseys some critters make seem incomprehensible. Arctic tern chicks take part in the longest migration on Earth—more than ten thousand miles (16,000 km)—almost as soon as they fledge. Soon after hatching, young sea turtles take to the waves and confidently paddle many thousands of miles to feeding grounds. Young Chinook salmon likewise make their way from freshwater hatching grounds to specific feeding areas in the open ocean. Biologists know that these species are able to sense things that humans can’t, from the Earth’s magnetic field to extremely faint scents, that could help with navigation. But they may also be inheriting some specific knowledge of the paths they have to follow. A paper in this week’s Current Biology reports that young salmon appear to possess an inborn map of the geomagnetic field that can help them get where they need to go. The researchers, who are primarily based at Oregon State University, performed a series of experiments with Chinook salmon less than a year old that were born and raised in a hatchery and had not yet taken part in a migration. They placed the salmon in pools surrounded by magnetic coils that they could tune to mimic the Earth’s magnetic field at various points in and around the salmons’ feeding grounds. (Kenneth Lohmann at University of North Carolina, Chapel Hill, who has done similar studies that established that baby sea turtles have inborn maps, is also an author of the paper.) © 2014 Time Inc.

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 19220 - Posted: 02.08.2014

Associated Press It's the ape equivalent of Google Maps and Facebook. The night before a big trip, Arno the orangutan plots his journey and lets others know where he is going with a long, whooping call. What he and his orangutan buddies do in the forests of Sumatra tells scientists that advance trip planning and social networking aren't just human traits. A new study of 15 wild male orangutans finds that they routinely plot out their next-day treks and share their plans in long calls, so females can come by or track them, and competitive males can steer clear. The researchers closely followed the males as they traveled on 320 days during the 1990s. The results were published Wednesday in the journal PLoS One. Typically, an orangutan would turn and face in the direction of his route and let out a whoop, sometimes for as long as four minutes. Then he'd go to sleep and 12 hours later set on the heralded path, said study author Carel van Schaik, director of the Anthropological Institute at the University of Zurich. "This guy basically thinks ahead," van Schaik said. "They're continuously updating their Google Maps, so to speak. Based on that, they're planning what to do next." The apes didn't just call once - they kept at it, calling more than 1,100 times over the 320 days. © 2013 The Hearst Corporation

Related chapters from BP7e: Chapter 19: Language and Hemispheric Asymmetry; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 15: Language and Our Divided Brain
Link ID: 18638 - Posted: 09.12.2013

By Susan Milius Here’s a lesson on road trips from whooping cranes: For efficient migration, what matters is the age of the oldest crane in the group. These more experienced fliers nudge youngsters away from going off course on long flights. “The older birds get, the closer they stick to the straight line,” says ecologist Thomas Mueller of the University of Maryland in College Park, who crunched data from 73 Grus americana migrating between Wisconsin and Florida. One-year-olds traveling with other birds of the same age, the analysis says, tend to deviate about 76 kilometers from a direct route. But if they fly in a group with an 8-year-old crane, they stray 38 percent less, or about 47 kilometers, Mueller and his colleagues report in the August 30 Science. Eight years of data on these endangered cranes summering in Wisconsin’s Necedah National Wildlife Refuge offered a rare chance to parse how birds find their way. Conservationists have been rebuilding this eastern migratory population of the once widespread birds. Researchers release captive-bred cranes in Wisconsin and lead each class of newbies, just once, with an ultralight aircraft to Florida’s Chassahowitzka National Wildlife Refuge for the winter. Cranes navigate back to Wisconsin on their own. © Society for Science & the Public 2000 - 2013

Related chapters from BP7e: Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 18591 - Posted: 08.31.2013

By Ella Davies Reporter, BBC Nature An unusual caterpillar uses the sun to navigate as it jumps to safety, according to scientists. The larva of Calindoea trifascialis, a species of moth native to Vietnam, wraps itself in a leaf before dropping to the forest floor. It then spends three days searching for a suitable place to pupate, despite not being able to see out of its shelter. Experts found the insect used a piston-like motion to jump away from strong sunlight. "We believe the object of the jumping is to find shade - to avoid overheating and desiccation," explained Mr Kim Humphreys from the Royal Ontario Museum, Canada who conducted the research alongside Dr Christopher Darling. Their findings are published in the Royal Society journal Biology Letters. Although Mr Humphreys described the caterpillar as "non-descript" in appearance, he said its behaviour makes it unique in a number of ways. "Caterpillars or larvae that jump are rare in themselves," he said. "[This] caterpillar is remarkable for its jumping, which no other insect does in this way. It also makes its own vehicle [or] shelter to jump in." "It is also the only one I know of that jumps in an oriented way." BBC © 2013

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 7: Vision: From Eye to Brain; Chapter 5: The Sensorimotor System
Link ID: 18539 - Posted: 08.21.2013

by Katia Moskvitch In the days before GPS, we needed both a compass and a map to navigate. Migrating birds are no different. Studies have suggested that the animals rely on an internal map and compass to traverse large distances, though just where these senses reside is unclear. Now, scientists say they have the strongest evidence yet that map sense is associated with the beak. Researchers have long suspected that migrating birds navigate by sensing Earth's magnetic field. The idea was that their beaks, which contain a lot of iron, worked like real magnets, with the metal aligning itself relative to the field. Supposedly, the so-called trigeminal nerve transmitted this information to the brain. But in 2009, a team led by Henrik Mouritsen of the University of Oldenburg in Germany cut the trigeminal nerve in several European robins and found that the animals still oriented perfectly. In lab-based experiments, the birds were able to locate the natural and artificial magnetic north. It seemed that the beak played no role in the compass sense. The finding gave support to another hypothesis, one that suggested that the inner compass was instead a magnetism-sensing chemical reaction in the birds' eyes. But Mouritsen's team was still convinced that the beak had to be involved in the magnetosense in some way, and it decided to do another test. In 2010 and 2011, the scientists captured 57 Eurasian reed warblers near Kaliningrad, Russia. Every spring, these birds migrate northeast to their breeding grounds in southern Scandinavia, up to 1000 kilometers away. Once again, the scientists snapped the trigeminal nerve, in half of the birds. But then they also moved all 57 birds 1000 kilometers to the east, where the magnetic field differs from their home site, and released them. © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 5: The Sensorimotor System
Link ID: 18327 - Posted: 06.29.2013