Monday, February 27, 2012

Bird Brains Follow the Beat.

The budgerigar, Melopsittacus undulates, is one of several vocal-learning species of parrot, well known for its capacity to mimic human language. (Credit: Copyright : 2011 Yoshimasa Seki).
Source: Science Daily
ScienceDaily (Feb. 24, 2012) — By training birds to 'get rhythm', scientists uncover evidence that our capacity to move in time with music may be connected with our ability to learn speech.
Even though typical dance-floor activity might suggest otherwise, humans generally demonstrate a remarkable capacity to synchronize their body movements in response to auditory stimuli. But is this ability to move in time to musical rhythm a uniquely human trait?
Some animals are capable of vocal learning, changing the sounds they make in response to those they hear from other members of their species. Scientists have hypothesized that such behavior may be associated with the capacity for so-called 'rhythmic synchronization'. "Motor control of vocal organs is naturally important in vocal learning," says Yoshimasa Seki of the RIKEN Brain Science Institute in Wako. "Once auditory-motor coordination in the vocal control system has been established, a similar auditory-motor transformation system for other body parts might be derived from that."
Studies in vocal-learning species have largely focused on case studies of individual animals, but Seki and colleagues conducted larger-scale experiments and found that budgerigars (Fig. 1) may have an inherent capacity for rhythmic synchronization. The researchers tested their hypothesis by training eight budgerigars to peck a button in response to the rhythm of an external metronome, which could be adjusted to present the birds with audio-visual stimuli at varying intervals.
In all 46 experiments, the birds were able to consistently respond to rhythmic beats within a certain time-frame, demonstrating successful entrainment. However, the accuracy of their timing was dependent on the tempo. Only one out of seven birds was successfully able to match the onset of each beat when the stimuli were generated at 450 millisecond intervals, while all animals achieved this feat when that interval was lengthened to 1,500 or 1,800 milliseconds.
To confirm that actual synchronization was taking place, the researchers used computer simulations of other bird behavior scenarios, such as random pecking or responding directly to individual stimuli rather than the rhythm itself. However, none of these alternative models was sufficient to explain the observed activity. "Our results showed that budgerigars can show rhythmic movements synchronized with external stimuli, which means they potentially have this capability of auditory-motor entrainment as a species," says Seki.
As such, this species may offer a useful model for future investigations of the neurological mechanisms that potentially connect vocal learning with rhythmic synchronization in both birds and humans. "Such studies should contribute to discussions of specific characteristics of the human speech system and its similarity to the vocal learning systems found in other animal species," explains Seki.

Sunday, January 17, 2010

Wild Crows Reveal Tool Skills.

A new study using motion sensitive video cameras has revealed how New Caledonian crows use tools in the wild. (Credit: Copyright University of Oxford.
Source: ScienceDaily
ScienceDaily (Jan. 17, 2010) — A new study using motion sensitive video cameras has revealed how New Caledonian crows use tools in the wild.
Previous work has shown the sophisticated ways in which crows can use tools in the laboratory, but now a team of scientists from Oxford University and the University of Birmingham have investigated tool use in its full ecological context. The researchers recorded almost 1,800 hours of video footage for the study and published their findings in Proceedings of the Royal Society B.
In the wild, New Caledonian crows use tools for many purposes, including 'fishing out' large beetle larvae from holes in dead wood. In the new study, the team was able to show for the first time that more larvae were extracted by crows using tools than with their beaks.
They also discovered that adult crows appeared to be much more skilled at obtaining larvae than juvenile crows, suggesting that considerable learning -- possibly from copying more experienced 'larvae fishers' -- is required for crows to become competent at this task.
Aside from recording the video footage the team also collected a large sample of tools that crows had left inserted into larvae burrows. By comparing the length of the tools to the burrows, they found that, on average, longer tools are found in deeper burrows -- suggesting that wild crows, like their cousins in the laboratory, are able to match the 'right' tool to the task. The collection also showed that wild crows do not select tools randomly, from debris on the forest floor, but are more likely to choose leaf-stems than twigs, and are more likely to use tools of a certain size range.
The research team included Dr Lucas Bluff, Dr Christian Rutz, Dr Alex Weir and Professor Alex Kacelnik from Oxford University's Department of Zoology, and Jolyon Troscianko from the University of Birmingham.
The work was funded by the UK's Biotechnology and Biological Sciences Research Council (BBSRC).
Story Source:
Adapted from materials provided by
University of Oxford.
Journal Reference:
Bluff et al. Tool use by wild New Caledonian crows Corvus moneduloides at natural foraging sites. Proceedings of The Royal Society B Biological Sciences, 2010; DOI:

Polar Bear Droppings Advance Superbug Debate.

Researchers found little sign of superbugs in the droppings of polar bears that have had limited or no contact with humans, suggesting that the spread of antibiotic resistance genes seen in other animals may be the result of human influence. (Credit: iStockphoto/David Yang)
Source: ScienceDaily
ScienceDaily (Jan. 15, 2010) — Scientists investigating the spread of antibiotic-resistant superbugs have gone the extra mile for their research -- all the way to the Arctic. Researchers writing in the open access journal BMC Microbiology found little sign of the microbes in the droppings of polar bears that have had limited or no contact with humans, suggesting that the spread of antibiotic resistance genes seen in other animals may be the result of human influence.
Trine Glad, from the University of Tromsø, Norway, led a study that examined feces samples from five polar bears and rectal swabs from another five polar bears between 2004 and 2006. She said, "The presence of antibiotic resistance genes has previously been described in bacteria taken from the feces of deer, foxes, pigs, dogs and cats. The Barents Sea population of polar bears is located in an area that is sparsely populated by humans. This enables us to study an ecosystem with little human impact and should allow us to determine whether these genes are naturally occurring or are caused by exposure to human antibiotics."
The researchers found that there was scant evidence of antibiotic resistance genes in the bacteria taken from these isolated bears. Overall, the bacterial diversity in the bears' feces was low. Speaking about these results, Glad said "Our analysis of polar bear feces showed a homogenous microbial flora dominated by Clostridia, most of them well characterized as they are also dominant in the human gut. These findings fit nicely with previous studies of the gut microbial ecology in mammals, indicating that bacterial diversity is lower in carnivores, such as polar bears that feed mostly on seals, than herbivores."
Story Source:
Adapted from materials provided by
BioMed Central, via EurekAlert!, a service of AAAS.
Journal Reference:
Trine Glad, Pal Bernhardsen, Kaare M Nielsen, Lorenzo Brusetti, Magnus Andersen, Jon Aars and Monica A Sundset. Bacterial diversity in faeces from polar bear (Ursus maritimus) in Arctic Svalbard. BMC Microbiology, (in press) [

Friday, January 15, 2010

New System Helps Explain Salmon Migration.

DOE/Pacific Northwest National Laboratory researchers helped develop the Juvenile Salmon Acoustic Telemetry System to study the migration of juvenile salmon through fast-moving rivers. (Credit: Pacific Northwest National Laboratory)
Source: ScienceDaily
ScienceDaily (Jan. 15, 2010) — A new acoustic telemetry system tracks the migration of juvenile salmon using one-tenth as many fish as comparable methods, suggests a paper published in the January edition of the American Fisheries Society journal Fisheries. The paper also explains how the system is best suited for deep, fast-moving rivers and can detect fish movement in more places than other tracking methods.
The Juvenile Salmon Acoustic Telemetry System (JSATS) estimated the survival of young, ocean-bound salmon more precisely than the widely used Passive Integrated Transponder (PIT) tags during a 2008 study on the Columbia and Snake rivers, according to the results of a case study discussed in the paper. The paper also concludes that fish behavior is affected least by light-weight JSATS tags compared to larger acoustic tags.
"Fisheries managers and researchers have many technologies to choose from when they study fish migration and survival," said lead author Geoff McMichael of the Department of Energy's Pacific Northwest National Laboratory.
"JSATS was specifically designed to understand juvenile salmon passage and survival through the swift currents and noisy hydroelectric dams on the Columbia River," McMichael continued. "But other systems might work better in different circumstances. This paper demonstrates JSATS' strengths and helps researchers weigh the pros and cons of the different fish tracking methods available today."
Scientists at PNNL and the U.S. Army Corps of Engineers' Portland District co-authored the paper. PNNL and NOAA Fisheries began developing JSATS for the Corps in 2001.
JSATS is an acoustic telemetry system that includes the smallest available acoustic transmitting tag, which weighs 0.43 grams. Its battery-powered tags are surgically implanted into juvenile salmon and send a uniquely coded signal every few seconds. Receivers are strategically placed in waterways to record the signal and track when and where tagged fish travel. A computer system also calculates the precise 3-D position of tagged fish using data gathered by the receivers.
PIT tags are also implanted into juvenile salmon for migration and survival studies, but don't use batteries to actively transmit signals. Instead, PIT tags send signals when they become energized while passing by PIT transceiver antennas.
For the paper's case study, researchers implanted 4,140 juvenile Chinook salmon with both JSATS and PIT tags. They also placed just PIT tags inside another 48,433 juveniles. All of the case study's tagged fish were released downstream of Lower Granite Dam on the Snake River in April and May 2008.
A significantly greater percentage of JSATS tags were detected than PIT tags, the case study demonstrated. For example, about 98 percent of JSATS-tagged fish were detected at Ice Harbor Dam on the Snake River. About 13 percent of PIT-tagged fish were detected in the same stretch of river. As a result, studies using JSATS require using roughly one-tenth as many fish as those employing PIT tags, which helps further conserve the salmon population.
Survival estimates were similar between JSATS and PIT tags. Forty-eight percent of the JSATS-tagged fish were estimated to have survived migration between Lower Granite Dam and Bonneville Dam, which is the last dam on the Columbia before the Pacific Ocean. For PIT-tagged fish, 43 percent were estimated to have reached the same area.
Having flexibility in where receivers can be placed is advantageous, the authors reported. JSATS receivers can be located in both rivers and dams, while PIT antennas usually can only go inside fish bypasses at dams. Researchers can estimate fish survival for an entire river system when receivers are placed in more locations, the paper explains.
The team also compared JSATS' technical features with those of another acoustic telemetry system, the VEMCO system being used for the Pacific Ocean Shelf Tracking (POST) project along North America's West Coast. The VEMCO system is best suited for use in the slow-moving, open ocean when observing small numbers of large fish, the authors wrote. In contrast, JSATS was developed to study the migration of larger quantities of small juvenile fish in fast-moving rivers.
A key difference between the JSATS and VEMCO systems is dry tag weight. JSATS tags weigh 0.43 grams and are the smallest acoustic tags available. VEMCO tags that have been used in Columbia River juvenile salmon weighed 3.1 grams. Previous research shows fish can bear a tag that weighs up to 6.7 percent of their body weight without significant adverse survival effects. That means JSATS tags can be implanted into fish as light as 6.5 grams, while VEMCO tags should be used in fish that weigh no less than 46.3 grams.
Another advantage of JSATS is that it is non-proprietary and available for anyone to manufacture or use. Because several companies have been able to competitively bid for the opportunity to produce the system's components, its cost has dropped in recent years. JSATS tags, for example, have gone from $300 per tag in 2005 to $215 in 2008. And JSATS tags cost $40 to $135 less than other commercially available acoustic tags in 2008. Proprietary interests have hindered the development of acoustic telemetry equipment in certain areas, the team wrote.
"JSATS has helped us get a clearer, more complete picture of how salmon migrate and survive through the Columbia and Snake rivers to the Pacific Ocean," McMichael said. "But we're continuing to develop JSATS and hope others will find it useful in studies of other aquatic animals. There's an opportunity for all aquatic telemetry technologies to be improved."
Story Source:
Adapted from materials provided by
DOE/Pacific Northwest National Laboratory.
Journal Reference:
G.A. McMichael, M.B. Eppard, T.J. Carlson, J.A. Carter, B.D. Ebberts, R.S. Brown, M. Weiland, G.R. Ploskey, R.A. Harnish and Z.D. Deng. The Juvenile Salmon Acoustic Telemetry System: A New Tool. Fisheries, Vol. 35, No. 1, January 2010

'World's Least Known Bird' Discovered Breeding in Afghanistan.

Researchers from the Wildlife Conservation Society have discovered the only known breeding area for the large-billed reed warbler, once called "the world's least known bird species." (Credit: WCS-Afghanistan)
ScienceDaily (Jan. 15, 2010) — Researchers for the Wildlife Conservation Society have discovered for the first time the breeding area of the large-billed reed warbler -- dubbed in 2007 as "the world's least known bird species" -- in the remote and rugged Wakhan Corridor of the Pamir Mountains of north-eastern Afghanistan.
Using a combination of astute field observations, museum specimens, DNA sequencing, and the first known audio recording of the species, researchers verified the discovery by capturing and releasing almost 20 birds earlier this year, the largest number ever recorded.
A preliminary paper on the finding appears in the most recent edition of BirdingASIA. The authors include: Robert Timmins, Naqeebullah Mostafawi, Ali Madad Rajabi, Hafizullah Noori, Stephane Ostrowski and Colin Poole, of the Wildlife Conservation Society; Urban Olsson of Göteborg University, Sweden; and Lars Svensson.
The recent discovery of large-billed reed warblers in Afghanistan represents a watershed moment in the study of this bird, called in 2007 the world's least known bird species by BirdLife International. The first specimen was discovered in India in 1867, with more than a century elapsing before a second discovery of a single bird in Thailand in 2006.
"Practically nothing is known about this species, so this discovery of the breeding area represents a flood of new information on the large-billed reed warbler," said Colin Poole, Executive Director of WCS's Asia Program. "This new knowledge of the bird also indicates that the Wakhan Corridor still holds biological secrets and is critically important for future conservation efforts in Afghanistan."
The find serves as a case study in the detective work needed to confirm ornithological discoveries. The story begins in 2008, when Timmins was conducting a survey of bird communities along the Wakhan and Pamir Rivers. He immediately heard a distinctive song coming from a small, olive-brown bird with a long bill. Timmins taped the bird's song. He later heard and observed more birds of the same species.
Initially, Timmins assumed these birds to be Blyth's reed warblers, but a visit to a Natural History Museum in Tring, United Kingdom to examine bird skins resulted in a surprise: the observed birds were another species. Lars Svensson -- an expert on the family of reed warblers and familiar with their songs -- then realized that Timmins' tape was probably the first recording of the large-billed reed warbler.
The following summer (June 2009), WCS researchers returned to the site of Timmins' first survey, this time with mist nets used to catch birds for examination. The research team broadcast the recording of the song, a technique used to bring curious birds of the same species into view for observation and examination. The recording brought in large-billed reed warblers from all directions, allowing the team to catch almost 20 of them for examination and to collect feathers for DNA. Later lab work comparing museum specimens with measurements, field images, and DNA confirmed the exciting finding: the first-known breeding population of large-billed reed warblers.
WCS is currently the only organization conducting ongoing scientific conservation studies in Afghanistan -- the first such efforts in over 30 years -- and has contributed to a number of conservation initiatives and activities in partnership with the Afghanistan Government, with support from USAID (United States Agency for International Development). In 2009, the government of Afghanistan gazetted the country's first national park, Band-e-Amir, established with technical assistance from WCS's Afghanistan Program. WCS also worked with Afghanistan's National Environment Protection Agency (NEPA) in producing the country's first-ever list of protected species, an action that now bans the hunting of snow leopards, wolves, brown bears, and other species. In a related effort, WCS now works to limit illegal wildlife trade in the country through educational workshops for soldiers at Bagram Air Base and other military bases across Afghanistan.
Situated between the mountainous regions of the Pamirs in Tajikistan, Pakistan, and China, the Wakhan Corridor supports a surprisingly wide range of large mammal species, including Marco Polo sheep (or argali), ibex, lynx, wolf, and the elusive snow leopard.
Story Source:
Adapted from materials provided by
Wildlife Conservation Society, via EurekAlert!, a service of AAAS.

Alligators Breathe Like Birds, Study Finds.

Computerized tomographic (CT) X-ray images of side and top views of a 24-pound American alligator, with 3-D renderings of the bones and of airways or bronchi within the lungs. The windpipe and first-tier of bronchi are not shown. A University of Utah study found that air flows in one direction through a gator's lungs. It flows from the first-tier bronchi through second-tier bronchi (blue), then through tube-like third-tier parabronchi (not shown) and then back through other second-tier bronchi (forest green). (Credit: C.G. Farmer and Kent Sanders, University of Utah.)
Source: ScienceDaily
ScienceDaily (Jan. 15, 2010) — University of Utah scientists discovered that air flows in one direction as it loops through the lungs of alligators, just as it does in birds. The study suggests this breathing method may have helped the dinosaurs' ancestors dominate Earth after the planet's worst mass extinction 251 million years ago.
Before and until about 20 million years after the extinction -- called "the Great Dying" or the Permian-Triassic extinction -- mammal-like reptiles known as synapsids were the largest land animals on Earth.
The extinction killed 70 percent of land life and 96 percent of sea life. As the planet recovered during the next 20 million years, archosaurs (Greek for "ruling lizards") became Earth's dominant land animals. They evolved into two major branches on the tree of life: crocodilians, or ancestors of crocodiles and alligators, and a branch that produced flying pterosaurs, dinosaurs and eventually birds, which technically are archosaurs.
By demonstrating one-way or "unidirectional" airflow within the lungs of alligators, the new study -- published in the Jan. 15 issue of the journal Science -- means that such a breathing pattern likely evolved before 246 million years ago, when crocodilians split from the branch of the archosaur family tree that led to pterosaurs, dinosaurs and birds.
That, in turn, means one-way airflow evolved in archosaurs earlier than once thought, and may explain why those animals came to dominance in the Early Triassic Period, after the extinction and when the recovering ecosystem was warm and dry, with oxygen levels perhaps as low as 12 percent of the air compared with 21 percent today.
"The real importance of this air-flow discovery in gators is it may explain the turnover in fauna between the Permian and the Triassic, with the synapsids losing their dominance and being supplanted by these archosaurs," says C.G. Farmer, the study's principal author and an assistant professor of biology at the University of Utah. "That's the major reason this is important scientifically."
Even with much less oxygen in the atmosphere, "many archosaurs, such as pterosaurs, apparently were capable of sustaining vigorous exercise," she adds. "Lung design may have played a key role in this capacity because the lung is the first step in the cascade of oxygen from the atmosphere to the animal's tissues, where it is used to burn fuel for energy."
Farmer emphasized the discovery does not explain why dinosaurs, which first arose roughly 230 million years ago, eventually outcompeted other archosaurs.
Farmer conducted the study -- funded by the National Science Foundation -- with Kent Sanders, an associate professor of radiology at the University of Utah School of Medicine. They performed CT scans of a 4-foot-long, 24-pound alligator.

'The Great Dying' -- Decline of the Synapsids, Rise of the Archosaurs:
The synapsids -- which technically include modern mammals -- occupied ecological niches for large animals before the Permian-Triassic extinction.
"Some got up to be bear-sized," says Farmer. Some were meat-eaters, others ate plants. They were four-footed and had features suggesting they were endurance runners. Their limbs were directly under their body instead of sprawling outward like a lizard's legs. There is evidence they cared for their young.
The cause of the mass extinction 251 million years ago is unknown; theories include massive volcanism, an asteroid hitting Earth and upwelling of methane gas that had been frozen in seafloor ice.
"A few of the synapsids survived the mass extinction to re-establish their dominance in the early Triassic, and the lineage eventually gave rise to mammals in the Late Triassic," says Farmer. "However, the recovery of life in the aftermath of the extinction involved a gradual turnover of the dominant terrestrial vertebrate lineage, with the archosaurs supplanting the synapsids by the Late Triassic."
From then until the dinosaurs died out 65 million years ago, any land animal longer than about 3 feet was an archosaur, says Farmer, while mammal-like synapsid survivors "were teeny little things hiding in cracks. It was not until the die-off of the large dinosaurs 65 million years ago that mammals made a comeback and started occupying body sizes larger than an opossum."
No one knows much about the archosaur that was the common ancestor of crocodilians and of pterosaurs, dinosaurs and birds, Farmer says.
It probably was "a small, relatively agile, insect-eating animal," Farmer says. Illustrations of early archosaurs look like large lizards.
"Our data provide evidence that unidirectional flow [of air in the lungs] predates the origin of pterosaurs, dinosaurs and birds, and evolved in the common ancestor of the crocodilian and bird [and pterosaur and dinosaur] lineages," Farmer says.

Cul-de-sacs or Loops for Airflow:
In the lungs of humans and other mammals, airflow is like the tides. When we inhale, the air moves through numerous tiers of progressively smaller, branching airways, or bronchi, until dead-ending in the smallest chambers, cul-de-sacs named alveoli, where oxygen enters the blood and carbon dioxide moves from the blood into the lungs.
It long has been known that airflow in birds is unidirectional, and some scientists suggest it also was that way in dinosaurs.
In modern birds, the lungs' gas exchange units are not alveoli, but tubes known as "parabronchi," through which air flows in one direction before exiting the lung. Farmer says this lung design helps birds fly at altitudes that would "render mammals comatose."
Some researchers have argued that unidirectional airflow evolved after crocodilians split from the archosaur family tree, arising among pterosaurs and theropod dinosaurs, the primarily meat-eating group that included Tyrannosaurus rex. Others have argued it arose only among coelurosaurs, a group of dinosaurs that also includes T. rex and feathered dinosaurs.
Unidirectional air flow in birds long has been attributed to air sacs in the lungs. But Farmer disagrees, since gators don't have air sacs, and says it's due to aerodynamic "valves" within the lungs. She believes air sacs help birds redistribute weight to control their pitch and roll during flight. Farmer says many scientists simply assume air sacs are needed for unidirectional airflow, and have pooh-poohed assertions to the contrary.
"They cannot argue with this data," she says. "I have three lines of evidence. If they don't believe it, they need to get an alligator and make their own measurements."

Assessing Airflow in Alligators:
Farmer did three experiments to demonstrate one-way airflow in alligators' lungs:
She performed surgery on six anesthetized alligators and inserted flow meters called thermistors into the lungs to measure airflow speed and direction.
-Farmer pumped air in and out of lungs removed from four dead alligators sent to her by a wildlife refuge in Louisiana. The flow was monitored, showing the air kept going the same direction to loop through various tiers of bronchi and back to the trachea.
-Using lungs from another dead gator, she pushed and pulled water with tiny fluorescent beads through the lungs, making movies showing the unidirectional flow.
Farmer says the fact gator lungs still had unidirectional flow after being removed shows unidirectional airflow is caused by aerodynamic valves within the lungs, and not by some other factor, like air sacs or the liver, which acts like a piston to aid breathing.
How does air loop through an alligator's multichambered lungs?
Inhaled air enters the trachea, or windpipe, and then flows into two primary bronchi, or airways. Each of those primary bronchi enters a lung.
From those primary airways, the bronchi then branch into a second tier of narrower airways. Inflowing air jets past or bypasses the first branch in each lung because the branch makes a hairpin turn away from the direction of airflow, creating an aerodynamic valve. Instead, the air flows into other second-tier bronchi and then into numerous, tiny, third-tier airways named parabronchi, where oxygen enters the blood and carbon dioxide leaves it.
The air, still moving in one direction, then flows from the parabronchi into the bypassed second-tier bronchi and back to the first-tier bronchi, completing a one-way loop through the lungs before being exhaled through the windpipe.
Story Source:
Adapted from materials provided by
University of Utah.

Thursday, January 14, 2010

Unlocking the mystery of the duck-billed platypus' venom.

Despite its cuddly look, the male duck-billed platypus has stingers on its hind limbs that can deliver a painful venom. Scientists are unraveling its chemical composition. Credit: Wikimedia Commons.
Abandon any notion that the duck-billed platypus is a soft and cuddly creature -- maybe like Perry the Platypus in the Phineas and Ferb cartoon.
This platypus, renowned as one of the few mammals that lay eggs, also is one of only a few venomous mammals. The males can deliver a mega-sting that causes immediate, excruciating pain, like hundreds of hornet stings, leaving victims incapacitated for weeks. Now scientists are reporting an advance toward deciphering the of the , with the first identification of a dozen protein building blocks. Their study is in the .
Masaki Kita, Daisuke Uemura, and colleagues note that spurs in the hind limb of the male platypus can deliver the venom, a cocktail of substances that cause excruciating pain. The scientists previously showed that the venom triggers certain chemical changes in cultured human nerve cells that can lead to the sensation of pain. Until now, however, scientists did not know the exact components of the venom responsible for this effect.
To unlock its secrets, the scientists collected samples of
venom and used high-tech analytical instruments to separate and characterize its components. They identified 11 new , or protein subunits, in the venom. Studies using nerve cells suggest that one of these substances, called Heptapeptide 1, is the main agent responsible for triggering pain. The substance appears to work by interacting with certain receptors in the nerve cells, they suggest.
More information: "Duck-Billed Platypus Venom Peptides Induce Ca2+ Influx in Neuroblastoma Cells",
Provided by American Chemical Society.