Saturday, 6 August 2011
Picked Punks have been a part of every well stocked cabinet of curiosity and perhaps the most controversial of all sideshow exhibits. A ‘Pickled Punk’ is a sideshow term for a preserved human fetus, usually deformed and usually displayed as a specimen in a jar or other vessel.
The practice of preserving and displaying prodigious births is centuries old. In the 1600’s King Frederick III of Denmark has a personal collection of punks numbering in the thousands – a collection started in the 1500’s by Frederick II. and during that same timeframe Ulisse Aldrovandi, an Italian naturalist, had a collection consisting of eighteen thousand various specimens.
The deformities present in pickled punks are incredibly varied. As varied as the nature of human inflictions.
The earliest and most well documented pedigree for a deformed punk display dates back to 1582 when Mme Colombe Chatri died at the age of sixty-eight – and a twenty-eight year old fetus was removed from her womb. The Stone-Child of Sens should have been born in 1554, however labor came and went with no delivery and in the resulting decades the fetus was calcified and ossified within the womb – which actually formed a shell. Mme Chatri seemed to have lived a normal life, with the exception of regular abdominal pains. Following her death and the ‘delivery’ of the Stone-Child – naturalists clamored to claim the fetus and the right to display the tiny marvel. Jean d’Ailleboust wrote a detailed pamphlet in 1582 – complete with illustrations – about the case, which became an instant best seller. Pare featured the infant in his book Des monstres et prodiges and reveals that the child was sold to M. Prestesiegle, a wealthy merchant in the 1590’s. He sold it to a goldsmith named M. Carteron who in turn sold it in 1628 to M. Bodey, a jewel merchant complete with a sort of ‘certificate of authenticity’. In 1653, the Stone-Child came into the possession of King Frederick III as well as a handwritten copy of the d’Ailleboust paper. By this point, the child was heavily damaged, with both arms broken and the marble-like skin worn off in places.
The Stone-Child remained in the possession of the Royal Museum for decades, cataloged in 1696, 1710, 1737 and was transferred to the Danish Museum of Natural History in 1826. The Stone-Child went missing sometime in the late 1800’s – it is believed that is was literally scrapped by Professor Reinhardt when he was director of the museum as he believed it was not a ‘scientific display’.
Strangely enough, the Stone-Boy condition – known today as lithopedion – is not all that rare as some 290 cases exist in modern medical literature.
The classic pickled punk – floating in a jar of preserving fluid – became most popular during the golden age of sideshow and experienced a great resurgence in the 1950’s and 1960’s. During that era many punks were linked to drug abuse, at least in the banner lines outside. Several sideshows featured extensive punk displays – some authentic and others gaffed (faked). Following this era, laws began to restrict the display of punks. To complicate matters, laws differed from state to state – making traveling displays almost impossible. Furthermore, the question of whether punks qualify as ‘human remains’ further complicates the laws.
The great modern showman, Ward Hall, once had one of the largest punk shows in the United States. During one season he was fined due to the fact that the display of human remains was illegal in the state he had set up his show in. He replaced his punks with rubber replicas – called ‘bouncers’ – and continued his tour only to be fined again in another state for being a ‘conman’, displaying ‘fakes’ and ‘false advertising’.
While there are still a few stationary legitimate pickled punk shows in the sideshow tradition. Today the best place to find pickled punks is in research or university laboratories or medical museums – like the Mutter Museum in Philadelphia. The world’s largest collection of pickled punks, once owned by Peter the Great, is currently on display at the Kuntskammer Museum in St. Petersburg, Russia.
Friday, 5 August 2011
Scientists have identified the heat-sensitive facial nerves used by vampire bats to detect their next meal.The nerves allow bats to pinpoint where the blood flows closest to their prey's skin so they can feed more efficiently.
Vampire bats are among a handful of animals that use infrared sensors to locate their next meal, but are unique in the way they do it.
The findings are reported in the journal Nature.
- The Common Vampire Bat (Desmodus rotundus) is one of three species of vampire bat: The Hairy-legged Vampire Bat (Diphylla ecaudata), and the White-winged Vampire Bat (Diaemus youngi)
- All three live in the Central and South America
- D. rotundus feeds mainly on domestic animals, using its razor sharp teeth to make small (5mm) cuts in their prey - most often around the neck or vulva - and secretes an anticoagulant into the wound so it can draw enough blood to the surface
- D. rotundus drinks its body weight in blood each night, secreting blood plasma in its urine as it feeds to lighten the load
- Scientists have developed a anti-clotting drug from the saliva of vampire bats that could help stroke patients
Native to Central and South America, the Common Vampire Bat, Desmodus rotundus, needs to take a sanguineous slurp every night to survive.Researchers believe that the bats rely solely on detecting their next meal in the dark by listening out for their prey's breathing.
Having located a prey individual the bats crawls along the ground and onto the animal.
Once atop their prey, the bats are capable of using their heat-adapted nerves in their upper lip and nose to detect blood up to 20cm under their prey's flesh.
The new finding has pinpointed the molecule that is responsible - heat-sensitive TRPV1. TRPV1, a protein, usually helps animals detect dangerously high temperatures (those over 43 degrees C), but in the bats, some of the TRPV1 molecules have been mutated into a version that is sensitive to lower temperatures, those around 30 degrees C.
Lots of blood-sucking animals search out their next meal using heat-detecting molecules, but they all seem to do it in a different way, said bat biologist, Brock Fenton from the University of Western Ontario, who was not involved in the work.
He said that perceptual world of bats undoubtedly has many more intriguing secrets.
Thursday, 4 August 2011
"They look a bit like a sabre-toothed sausage," says Dr Chris Faulkes, as we enter the naked mole rat laboratory at Queen Mary, University of London.Scuttling around in a maze of tubes are dozens of small rodents. They appear to be hairless, covered with wrinkly, pink skin and they have beady, black eyes. But the thing that really catches your attention is their enormous, protruding teeth.
At first glance, it's clear that Dr Faulkes' description is spot on.
"It's a really, really bizarre looking animal," admits the scientist, who has spent the past 20 years studying naked mole rats.
These rodents, which belong to the African mole rat family, are found in parts of Kenya, Ethiopia and Somalia.
They live in huge underground burrows, which goes some way to explaining why these creatures look like they do - they use their giant teeth to help them dig.
Dr Faulkes says: "They are amazingly well adapted to living underground."
Busy as a bee But it isn't just their unusual appearance that attracts attention: their behaviour is about as strange as it gets in the mammalian world.
For a start, these little creatures live in huge groups. On average, you will find colonies made up of 80-100 individuals, but sometimes they can grow to a 300-strong group.
More bizarre still is their social structure.
Dr Faulkes points to a mole rat that looks almost twice as large as any nearby. And it is clearly pushing around some of its punier companions."That's the queen," he says. "Even in these really huge colonies, there is only a single female that breeds. And she mates with one or two, or sometimes three, breeding males.
"And then the rest of the colony, of both sexes, have their reproduction suppressed and never ever breed."
But the sex-free mole rats have another job, he explains.
"The small ones tend to act as workers, so they carry out colony maintenance activities," says Dr Faulkes.
The larger animals seem to adopt a more defensive role, he adds, keeping predators, such as snakes, at bay.
And if this kind of set up sounds rather familiar, that's because it is.
Dr Faulkes explains: "They behave like the mammalian equivalent of a social insect - they have many, many similarities with bees, ants, wasps and termites."
Throw in on top of this the fact that naked mole rats also live for an unfeasibly long time for a small rodent - 30 years in captivity - and that they also seem to be resistant to cancer, so it is easy to see why scientists are so interested in them.
"There are so many aspects of their biology that are extreme," says Dr Faulkes.
He, working with neuroscientist Professor Clive Coen, from King's College London, and zoologist Professor Nigel Bennett, from the University of Pretoria, has used this as the basis to find out what lies behind the naked mole rats' behaviour, and in turn, to start to look at how this might relate to other mammals - including humans.
And one way that they have been doing this is to compare naked mole rats with another member of the African mole rat family, the Cape mole rat.
Where the naked mole rat is a highly social animal and forms long-term social bonds, especially between the queen and her select suitors, the Cape mole rat is solitary and aggressive, and sexually, rather promiscuous.
Dr Faulkes says: "They represent both ends of the spectrum in sociability."
Earlier research carried out on voles had suggested that differences in the way that receptors for two hormones, oxytocin and vasopressin, were expressed in the brain could make a huge impact on social behaviour, including determining whether a species was likely to be monogamous or promiscuous.
So the team decided to look at whether these hormones could also be linked to the differences in behaviour between the two mole rat species.
Dr Faulkes explains: "We found that the naked mole rats and the Cape mole rats had substantially different patterns.
"The solitary, highly aggressive Cape mole rats had their oxytocin receptors distributed in a different part of the brain to the naked mole rats, while the naked mole rats' oxytocin receptors were found in the same region as monogamous voles."
He added: "This is really telling us that these kinds of systems of differing patterns of distribution for the oxytocin receptors are an important part of what underlies different kinds of social behaviour across mammals."
And while this research has focussed on mole rats, other research groups have been looking at the effects of these hormones on humans, including a recent study that suggested men who inhaled oxytocin became as empathetic as women.
Dr Faulkes says: "It seems even in humans that such changes can actually alter human reproductive behaviour, such as how stable relationships are.
"Some people have even linked mutations in the oxytocin receptor gene to certain types of autism."
But scientists are not just looking at social behaviour. They also think that naked mole rats could help us to sniff out answers to a whole host of questions linked to the human condition.
Some researchers are trying to find out whether the animals hold the key to longevity; others are looking at the clues they might give us in the fight against cancer; while some scientists want to see if they can help us to answer questions about reproduction and fertility.
Dr Faulkes says: "Although it might seem a bit of a stretch of the imagination to go from a naked mole rat to humans, the underlying biology is very, very similar.
"And they are just so unusual and there are so many aspects of their biology that are extreme that they could help us to extend our knowledge across so many species and disciplines."
Wednesday, 3 August 2011
Foot binding was initially a rather mild and harmless practice, performed by women attempting replicating the look of imperial concubine practices – who danced with their feet tightly wrapped in silk. But, by the Qing Dynasty (1636-1911), feet were forcibly bound so tightly and so early in life that crippling deformations resulted. Due to the fact that these women were deprived of autonomy and required constant assistance, foot binding became something of a status symbol.
Beginning as early as age five, the process was long and painful. Due to the tight binding four toes on each foot would break and become highly deformed within a year. Eventually a high arch was formed; the foot would become concave and resemble a ‘lotus blossom’. The ideal total foot length was to be no longer than 10 cm (4 in).
The Xiaohuayuan Shoe Factory in Shanghai still occasionally takes custom tiny shoe orders to accommodate the aged population affected by foot binding. Quite recently, a 90-year-old woman in Shanghai received a new pair of shoes. The shoes were a New Year’s gift from her son and daughter-in-law.
Tuesday, 2 August 2011
Smithsonian Magazine features a wonderful article on the ‘Tin Noses Shop’ of London. The London General Hospital’s Masks for Facial Disfigurement Department, founded by sculptor Francis Derwent Wood, created astounding prosthetic faces for the wounded soldiers of World War I.
The prosthetic masks were actually fashioned of galvanized and lightweight copper and weighed as little as four ounces. The facial features were originally painted on with oils until artist Anna Coleman Ladd, who went on to head a similar facility in Paris, developed an enamel technique that was washable and had a highly realistic finish. She painted the mask while the man himself was wearing it, so as to match as closely as possible his own coloring. All skin hues and details were painstakingly done by hand and Details such as eyebrows, eyelashes and mustaches were made from real hair. Each mask was a quite literally a masterpiece and changed lives. As one soldier wrote to Ladd:
‘Thanks to you, I will have a home. The woman I love no longer finds me repulsive, as she had a right to do.’
It is truly a shame that today the only images of these men in their masks come from black-and-white photographs.
Monday, 1 August 2011
Tapping into drivers' brain signals can cut braking distances and avoid car crashes, according to scientists.Researchers at the Berlin Institute for Technology attached electrodes to the scalps of volunteers inside a driving simulator.
The system detected the intention to brake, and cut more than 3m (10ft) off stopping distances, the team report in the Journal of Neural Engineering.
The team's next aim is to check the system in a series of road tests.
The 18 volunteers were asked to keep 20m (66ft) behind the simulated car in front, which braked sharply at random intervals.
Scientists used a technique called electroencephalograhy (EEG) to analyse the drivers' brain signals.
The system was able to pinpoint the intention to brake 13 hundredths of a second before the driver applied pressure to the brakes.
The team reported that at a speed of 100km/h (65m/h) the braking distance was reduced by 3.66 meters (12 feet).
Computer scientist Stefan Haufe told BBC News: "We know that any intention is generated in the brain. So it's no wonder that such things are visible in the brain.
"We were surprised it is so predictive. That is the thing!"
Lead investigator Benjamin Blankertz added: "It's quite easily explained by the fact that we can tap the driver's intention at the source of the build up of intention in the brain.
"It's a longer process, from the very first upcoming cognitive processes and intention building, until finally the muscles start the movement."
The volunteers also had the muscle tension in their lower legs analysed to detect the first signs of leg motion before they released the accelerator and pushed the brake pedal.
This data enabled the scientists to analyse the EEG information to determine which parts of the brain are key to braking. They improved the detection system accordingly.
'Point of no return' The Institute of Physics says this is the first time that EEG has been used to assist in braking.
The technique is, however, already used to help paralysed people control computers, prosthetic limbs and wheelchairs.
The researchers are planning to conduct road trials of their system to test its viability out of the lab.
But Benjamin Blankertz stressed that he suspects there may be some way to go before EEG can be used as a safety aid in real driving situations, not least because it requires the driver to wear a plastic cap with 64 electrodes covered in conductive gel.
This is uncomfortable, takes up to half an hour to fit, and the wearers have to wash the gel out of their hair afterwards. Smaller, more lightweight versions are in development.
The paper also mentions that wearers of EEG caps have to keep fairly still which is not always possible while driving, particularly when executing an emergency stop.
Dr Blankertz also said more work needs to be done on avoiding false alarms - to avoid the possibility that the machine could misread a drivers' brain signals and brake unnecessarily.
He said: "We need to investigate intention-building and decision-taking and self-initiated movement.
"Some recent research suggests that the outcome of free choices can be predicted from brain activity before the experimental subject is consciously aware of their intention.
"A technology that would make possible real time prediction of future decisions could be used to investigate how this relates to the so-called point of no return.
The team ultimately hopes to work with the automotive industry to combine their EEG technique with radar and laser systems that are used in some commercially available crash-avoidance systems, which detect obstacles such as walls, traffic signals and other vehicles.
Saturday, 30 July 2011
Noise "degrades" bat habitat for 50-60m either side of a busy highway
Traffic noise reduces bats' ability to locate their prey, say scientists.Researchers in Germany found that road noise affected the bats' ability to listen for the "rustling sound" of the beetles and spiders they feed on.
This is the first study to examine the impact of traffic on predators that listen for their prey.
The researchers report in the Royal Society journal Proceedings B that the same effect could be true for other "acoustic predators", including owls.
With their remarkably sensitive hearing, the bats detect and track down their prey by listening for the faint rustling sounds they produce when walking.
The bats are protected under the European Habitats directive, so the scientists' aim was to measure how any planned highways might affect their habitat.
To do this, they set up a flight test.
"We attempted to simulate the bats' foraging behaviour in our flight room," explained lead researcher Bjorn Siemers from the Max Planck Institute for Ornithology in Seewiesen.
In the wild, the bats fly about one metre above ground listening for rustling sounds.
"We had an array of 64 plates [on the floor of the flight room] each containing a speaker through which we could play this rustling sound," explained Dr Siemers.
When a bat landed on the right plate - the one from which the sound was being played - there would be a food reward waiting for it.
"On average it took five seconds for the bats to find the right plate," said Dr Siemers.
But when the team introduced traffic noise - via more loud speakers - into the flight room, the bats' performance declined.
Under the "strongest noise profiles" - which mimicked the sound of a busy highway just a few metres away - the bats took an average of 25 seconds to locate their treat.
"But even with the sound of a busy highway seven and a half metres away, they could still forage," said Dr Siemers.
"We were astonished by how well they coped with the noise, but their efficiency was greatly reduced."
Noise levels mimicking traffic up to 50m away affected the bats' ability to locate a meal.
This means, the researchers say, that each highway "degrades" an area of 50-60m of foraging habitat either side.
"It might not sound like much," Dr Siemers said, "but when you look at the thousands of kilometres of highway in a country like Germany, it adds up to quite a lot.
Friday, 29 July 2011
A young emperor penguin found washed up on a New Zealand beach is recovering well and could swim home next month.Staff at Wellington zoo said results of an X-ray and blood test showed "Happy Feet", as it has been named, is fine after endoscopic surgery.
The penguin was found on Peka Peka beach, about 60km (37 miles) north of Wellington - some 3,000km from its home in Antarctica.
Experts had been reluctant to intervene as the bird appeared to be healthy.
However, it later grew lethargic and was operated on to remove sand from its stomach.
A Zoo spokeswoman, Kate Baker, said the penguin has gained about 4kg (9lb).
It was given a first swim at the zoo earlier this week, in salt water that was cooled to below 0C (32F).
Crowds have been flocking to the zoo to see the bird - the first such arrival of an Emperor penguin in New Zealand in at least 44 years.
The bird's plight has attracted worldwide attention.
Hundreds of people had gathered to watch a leading gastroenterologist from Wellington Hospital perform the endoscopy on the bird at the zoo in late June.
To help it feel more at home, the penguin is being kept in a room chilled to about 8C. There is a bed of ice for it to sleep on.
Zoo staff said the bird would probably be released offshore from the south end of the country early next month.
Thursday, 28 July 2011
Humans living at high latitude have bigger eyes and bigger brains to cope with poor light during long winters and cloudy days, UK scientists have said.The Oxford University team said bigger brains did not make people smarter.
Larger vision processing areas fill the extra capacity, they write in the Royal Society's Biology Letters journal.
The scientists measured the eye sockets and brain volumes of 55 skulls from 12 populations across the world, and plotted the results against latitude.
Lead author Eiluned Pearce told BBC News: "We found a positive relationship between absolute latitude and both eye socket size and cranial capacity."
The team, from the Institute of Cognitive and Evolutionary Anthropology, used skulls dating from the 1800s kept at museums in Oxford and Cambridge.
The skulls were from indigenous populations ranging from Scandinavia to Australia, Micronesia and North America.
Largest brain cavities The largest brain cavities came from Scandinavia, while the smallest were from Micronesia.
Eiluned Pearce said: "Both the amount of light hitting the Earth's surface and winter day-lengths get shorter as you go further north or south from the equator.
"We found that as light levels decrease, humans are getting bigger eye sockets, which suggests that their eyeballs are getting bigger.
"They are also getting bigger brains, because we found this increase in cranial capacity as well.
"In the paper, we argue that having bigger brains doesn't mean that high-latitude humans are necessarily smarter. It's just they need bigger eyes and brains to be able to see well where they live."
The work indicates that humans are subject to the same evolutionary trends that give relatively large eyes to birds that sing first during the dawn chorus, or species such as owls that forage at night.
Co author Prof Robin Dunbar said: "Humans have only lived at high latitudes in Europe and Asia for a few tens of thousands of years, yet they seem to have adapted their visual systems surprisingly rapidly to the cloudy skies, dull weather and long winters we experience at these latitudes."
The team took into account the overall body size of each individual by measuring the foramen magnum - the hole in the base of the skull that attaches to the spinal column.
They also controlled for the possibility that the larger eye sockets were needed for extra fat around the eyeball to insulate them from freezing temperatures.
The team intends to do more work on establishing a firm link between eyeball size and enhanced visual processing areas in the brain, and to replicate the link found in the 55 original skulls with further study on specimens from other museums.
Wednesday, 27 July 2011
People with fewer qualifications are prone to age more quickly, a study which looked at 400 men and women says.DNA evidence suggests cellular ageing is more advanced in adults with no qualifications compared with those who have a university degree.
Experts think education might help people lead more healthy lives.
The British Heart Foundation said the London-based study, in journal Brain, Behaviour and Immunity, reinforced the need to tackle social inequalities.
The connection between health and socioeconomic status is well established.
Those from poor backgrounds are more likely to smoke more, take less exercise and have less access to good quality healthcare, compared with more wealthy people.
But the new study suggests that education might be a more precise determinant of a person's long term health rather than their current income and social status.
The researchers suggest that education may enable people to make better decisions that affect their long term health.
Professor Jeremy Pearson Associate Medical Director at the British Heart FoundationIt's not acceptable that where you live or how much you earn - or lesser academic attainment - should put you at greater risk of ill health”
They also speculate that well qualified people might be under less long-term stress, or be better able to deal with stress.Professor Andrew Steptoe, from University College London, who led the study, said: "Education is a marker of social class that people acquire early in life, and our research suggests that it is long-term exposure to the conditions of lower status that promotes accelerated cellular ageing."
Professor Steptoe's team took blood from more than 400 men and women aged between 53 and 75.
They then measured the length of sections of DNA found at the ends of chromosomes.
These sections - called "telomeres" - cap chromosomes, protecting them from damage. Shorter telomeres are thought to be an indicator of faster ageing.
The results showed that people with lower educational attainment had shorter telomeres, indicating that they may age faster.
They also indicated that telomere length was not affected by a person's social and economic status later in life, as was previously thought.
Social factors Professor Stephen Holgate, chairman of the Medical Research Council's Population and Systems Medicine Board, said the key implication of the study backs up the main message from long-term studies funded by the Medical Research Council for over half a century.
"Your experiences early in life can have important influences on your health," he explained.
"Whilst - as with all observational research - it is difficult to establish the root causes of the findings, this study does provide evidence that being educated to a higher level can benefit you more than in the job market alone."
Professor Jeremy Pearson, associate medical director at the British Heart Foundation, said the research reinforces the need to tackle social inequalities to combat ill-health.
He said: "It's not acceptable that where you live or how much you earn - or lesser academic attainment - should put you at greater risk of ill health."
The researchers were based primarily at University College London, but also collaborated with experts at the University of Wales Institute, Cardiff and the University of California, San Francisco.
Monday, 25 July 2011
A 'molecular scalpel' shows promise in patients with a deadly muscle wasting condition, according to researchers.The gene for the protein dystrophin is damaged in people with Duchenne muscular dystrophy.
A drug trial on 19 children, published in the Lancet, used the 'scalpel' to removed the damage and restore dystrophin production.
The charity Muscular Dystrophy Campaign said there was "real hope for the future".
Duchenne muscular dystrophy affects one in every 3,500 newborn boys.
Throughout life the muscle wastes away and children can need a wheelchair by the age of 10. The condition can become life-threatening before the age of 30, when it affects the muscles needed to breathe and pump blood around the body.
New approach The instructions for making a protein are in the genetic code, but this can be disrupted by mutations or deletions in the code.
Stem cell and gene therapy research has tried to find ways of introducing a functional dystrophin gene.
This study tried to do the best it could with the damaged code.
- Muscular dystrophies are a group of more than 20 different genetic neuromuscular disorders
- The most common, Duchenne muscular dystrophy (DMD), affects about one in 3,500 boys
- About 100 boys are born with the condition in the UK each year.
- Duchenne muscular dystrophy is caused by problems in a gene on the X chromosome that makes a protein called dystrophin, found in muscle fibres
- Muscle fibres break down and are gradually lost
- Another form - Becker muscular dystrophy - has similar but milder symptoms
The researchers at the Institute of Child Health at University College London injected tailored pieces of antisense RNA - the scalpel.This removed a piece of the genetic code allowing it to be matched up either side of the mutation.
The result is a shorter, but still functional, dystrophin.
In the trial, seven out of the 19 children had some degree of dystrophin production restored - all of them were receiving the highest doses.
Professor Francesco Muntoni, lead researcher, told the BBC: "The best result was 20% of normal dystrophin levels. That is quite remarkable considering the study was for 12 weeks.
"I've worked with patients with Duchenne muscular dystrophy for many years and this is the first time we can say with confidence that we've made a significant breakthrough towards finding a targeted treatment."
However, he said that as the scalpel was tailored to a specific mutation it could not benefit everyone, in this case around 13% of patients.
"The second most common mutation affects 11% - which needs another scalpel."
Dr Marita Pohlschmidt, director of the Muscular Dystrophy Campaign, said the study was "quite a big deal".
"If we can change severe symptoms in Duchenne into something milder, that would be fantastic.
"We have fought to find a treatment for this devastating condition for the past 50 years. Today we can say with real confidence that we're going to win that battle. Parents of these boys can have real hope for the future."
Sunday, 24 July 2011
A 120-million-year-old fossil is the oldest pregnant lizard ever discovered, according to scientists.The fossil, found in China, is a very complete 30cm (12in) lizard with more than a dozen embryos in its body.
Researchers from University College London, who studied the fossil, say it was just days from giving birth when it died and was buried during the Cretaceous period.
The team reports the findings in the journal Naturwissenschaften.
Prof Susan Evans University College LondonWhen I examined it under the microscope, I could see all these little babies”
The fossil is especially interesting to scientists because it is a reptile that produced live young rather than laying eggs.Only 20% of living lizards and snakes produce live young, and this shows it is an ancient, if unusual, trait.
"I didn't think much of the fossil when I first saw it," said Prof Susan Evans, joint lead author of the paper, from University College London.
But when her colleague, Yuan Wang, from the Chinese Academy of Sciences, examined the fossil he spotted the tiny remains of at least 15 almost fully developed embryos inside it.
"Sure enough, when I examined it under the microscope, I could see all these little babies," Prof Evans recalled.
The fossil is so well preserved that the minuscule teeth of the developing young are visible on very close inspection.
"This specimen is the oldest pregnant lizard we have seen," said Prof Evans.
"It implies physiological adaptations, like adequate blood supply to the embryos and very thin shells - or no shells at all - to allow oxygen supply, evolved very early on."
Up until now the fossil records only contained examples of marine lizards giving birth to live young.
Scientists thought that, in extinct reptiles, live birth was restricted to aquatic species, such as marine ichthyosaurs. These creatures would have been able to move through water with relative ease, even when heavily pregnant.
Prof Evans said: "We do know that this lizard lived near to water and we think it likely that they could swim even though they primarily lived on land.
"This would make sense as a pregnant lizard would be less constrained by carrying offspring - she'd be able to escape into water if a hungry dinosaur came along."
The fossil comes from world famous rocks of the Jehol Group in north-eastern China, where the fine limestone there has been worn away to gradually reveal hundreds of exquisite specimens of dinosaurs, but also fish, amphibians, reptiles, birds and mammals, plants and invertebrates.
The mother lizard has been identified as a specimen of Yabeinosaurus, a large, slow-growing and relatively primitive lizard.
Saturday, 23 July 2011
Previous studies estimated that chimps used about 30 different gestures
Wild chimpanzees use at least 66 distinct gestures to communicate with each other, according to scientists.A team of researchers from the University of St Andrews in Scotland filmed a group of the animals in order to decipher this "gestural repertoire".
The team then studied 120 hours of footage of the chimps interacting, looking for signs that the animals were intentionally signalling to each other.
The findings are published in the journal Animal Cognition.
Previous studies on captive chimps have suggested the animals have about 30 different gestures.
"So this [result] shows quite a large repertoire," lead researcher Dr Catherine Hobaiter told BBC News.
"We think people previously were only seeing fractions of this, because when you study the animals in captivity you don't see all their behaviour.
"You wouldn't see them hunting for monkeys, taking females away on 'courtships', or encountering neighbouring groups of chimpanzees."
Dr Hobaiter spent 266 days observing and filming a group of chimpanzees in Budongo Conservation Field Station, Uganda.
she said. "I follow them through the forest and they just ignore me completely and get on with their daily lives."
She and her colleague, Professor Richard Byrne, scrutinised the footage and categorised each distinct gesture.
They looked for clear signs that the animals were making deliberate movements that were intended to generate a response from another animal.
"We looked to see if the gesturer was looking at their audience," explained Professor Byrne.
"And we looked for persistence; if their action did not produce a result, they would repeat it."
The team is still studying the footage for the next stage of their project - to figure out what each gesture means.
For some of these gestures, the meaning seems obvious to us, perhaps because - as great apes- we make similar movements. A chimp will often beckon to another group member, or a youngster will hand shake at another juvenile to entice it to play.
In one piece of footage captured by Dr Hobaiter, a mother reaches with her left arm towards her daughter.
"The mother wants to move away and is gesturing to request that her daughter 'climbs on' her," Dr Hobaiter explained.
"She could just grab her daughter, but she doesn't. She reaches and holds the gesture while waiting for a response."
When the youngster starts to approach, the mother repeats the gesture and adds a facial expression - a "bare-teeth grin", at which point the daughter climbs on and they move away.
"But actions often have effects that their maker did not intend," said Professor Byrne.
"So to understand the intended meaning, it's no good just discovering a gesture's typical effect. We have to look for what effect makes the signaller stop gesturing and appear satisfied and content with the outcome, to be sure that that was what they intended."
The results have provided clues about the origins of chimps' gestures, suggesting that they are a common system of communication across the species, rather than each movement being a learned custom or ritual within one social group.
In fact, by comparing these observations with those of gestures made by gorillas and orangutans, the researchers showed there was significant overlap in the signals used throughout the family of great apes.
Dr Hobaiter said: This supports our belief that the gestures that apes use (and maybe some human gestures too) are derived from ancient shared ancestry of all the great ape species alive today."
Friday, 22 July 2011
Stick insects have lived for one million years without sex, genetic research has revealed.Scientists in Canada investigated the DNA of Timema stick insects, which live in shrubland around the west coast of the US.
They traced the ancient lineages of two species to reveal the insects' lengthy history of asexual reproduction.
The discovery could help researchers understand how life without sex is possible.
Scientists from Simon Fraser University, Canada, published their results in the journal Current Biology.Certain species of Timema stick insects were known to reproduce asexually, with females producing young in "virgin births" without the need for egg fertilisation by males.
The insects instead produce genetic clones of themselves.
Dr Tanja Schwander and her team set out to test how old these species were, and therefore to find out how long they had reproduced in this way.
By analysing the DNA of the insects, scientists were able to trace back their lineages to identify when they became a distinct species.
The team discovered that five of the asexual stick insects were "ancient", dating back more than 500,000 years. Two of them were even older.
"All the evidence points to Timema tahoe and Timema genevievae having persisted for over one million years without sex," Dr Schwander told BBC Nature.
"Our research adds to the growing amount of evidence that asexuality does not always result in the rapid extinction of a lineage," she said.
In the past, asexual reproduction has been associated with "evolutionary dead ends" because the lineages of organisms studied were often short-lived.
In more recent studies, tiny invertebrates called bdelloid rotifers and darwinulid ostracods were described as long-established asexuals by scientists investigating fossil records.
But there has been ongoing controversy surrounding these ancient asexuals. Further study suggested that asexuality was, in some cases, likely to have been a recent adaptation.
Asexual survival Dr Schwander and her team's genetic analysis confirmed that their stick insects have a long female-only history.
"Timema are indeed the oldest insects for which there is good evidence that they have been asexual for long periods of time," said Dr Schwander.
Comparing sexual and asexual species of stick insect could teach scientists more about how organisms survive without sex.
Asexuality does bring certain benefits, including rapid population growth. But the repeated cloning of genes through generations is thought to have significant negative consequences too.
This replication means that species are less able to adapt to new environments through "shuffling and tweaking" of genes.
Dr Schwander said: "Why Timema asexuals have been able to persist for so long despite all the predicted negative consequences of asexuality is the focus of ongoing studies."
Thursday, 21 July 2011
The grave containing the remains of Hitler's deputy Rudolf Hess has been destroyed to end it being used as a pilgrimage site by neo-Nazis.Hess's bones were exhumed at the graveyard in the small town of Wunsiedel, southern Germany, in the early hours of Wednesday morning.
The remains will be cremated and then scattered at sea.
Hess was captured in 1941 and sentenced to life in prison. He killed himself in jail in 1987 at the age of 93.
As he requested in his will, he was buried in the Bavarian town of Wunsiedel, where his family had a holiday home and where his parents were already interred.
The local Lutheran church which supervises the cemetery gave its permission for the burial at the time, ruling that the wishes of the deceased could not be ignored, the Suddeutsche Zeitung reports.
But they and local people have since become concerned by the number of far-right groups visiting the grave. Each year on the anniversary of his death, neo-Nazis have attempted to staged a march to the cemetery, saluting the grave, with its epitaph "I dared" and laying floral wreaths.
A 2005 court order banning such gatherings had little effect so the church decided to terminate the family's lease on the grave as of October 2011.
A granddaughter of Hess objected to the decision, the paper reports. She filed a lawsuit in an attempt to prevent it going ahead, but was eventually persuaded by the parish council to drop the case and allow the exhumation to go ahead.
Hess was one of Hitler's closest aides, but in 1941 he parachuted into Scotland in an apparently authorised solo peace mission, which was later denounced by the fuhrer.
He was imprisoned by the British for the duration of the war, and jailed for life at the Nuremberg trials in 1946. He spent 40 years in Spandau Prison in Berlin before being found hanged in his cell.
Wednesday, 20 July 2011
A mother's stress can spread to her baby in the womb and may cause a lasting effect, German researchers propose.They have seen that a receptor for stress hormones appears to undergo a biological change in the unborn child if the mother is highly stressed, for example, because of a violent partner.
And this change may leave the child less able to handle stress themselves.
It has already been linked to mental illness and behavioural problems.
The findings, published in the journal Translational Psychiatry, are based on a small study of 25 women and their children, now aged between 10 and 19.
And the researchers point out that the women involved in the study had exceptional home circumstances and that most pregnant women would not be exposed to such levels of stress day in and day out.
Furthermore, the researchers say the findings are not conclusive - many other factors, including the child's social environment while growing up, might be involved.
But they suspect it is the child's earliest environment, the womb, that is key.For their study, they looked at the genes of the mums and the adolescents to find any unusual patterns.
Some of the teens had changes to one particular gene - the glucocorticoid receptor (GR) - that helps regulate the body's hormonal response to stress.
Such genetic alterations typically happen while the baby is still developing in the womb.
And the scientists believe they are triggered by the mum-to-be's poor state of emotional wellbeing at the time of the pregnancy.
Sensitive window In the study, these mums had been living with the constant threat of violence from their husband or partner. And it would appear this continued stress took its toll on the pregnancy.
When the babies were followed up one to two decades later as adolescents, they had changes in the genetics of their GR that other teenagers did not.
This "methylation" of GR appears to make the individual more tuned in or sensitised to stress, meaning that they will react to it quicker both mentally and hormonally.
As people, they tend to be more impulsive and may struggle with their emotions, explain the researchers, who carried out detailed interviews with the adolescents.
Professor Thomas Elbert, one of the lead researchers at the University of Konstanz, said: "It would appear that babies who get signals from their mum that they are being born into a dangerous world are faster responders. They have a lower threshold for stress and seem to be more sensitive to it."
The investigators now plan to carry out more detailed investigations following larger numbers of mothers and children to see if they can confirm their suspicions.
Dr Carmine Pariante, an expert in the psychology of stress at the Institute of Psychiatry, King's College London, said: "This paper confirms that the early foundation years start at minus nine months."
He added: "Pregnancy is uniquely sensitive to a challenging maternal psychosocial environment - much more than, for example, after the baby is born. As we and others have been advocating, addressing maternal stress and depression in pregnancy is a clinically and socially, important strategy."
Tuesday, 19 July 2011
A love letter to a US college student from the girlfriend who was to become his wife is finally on its way to him - 53 years after it was written in 1958.The letter surfaced in a Pennsylvanian university mailroom earlier this month.
It was addressed to Clark C Moore, who has since changed his name to Muhammad Siddeeq, making it hard to trace him.
But a friend saw a TV report about it and contacted the sorting office. Mr Siddeeq, 74, says he is still eager to read it, despite now being divorced.
'Shocked' The letter mysteriously arrived at the California University of Pennsylvania, in the north-eastern state of Pennsylvania, 10 days ago.
Written to Mr Moore, the two-page letter was postmarked 20 February 1958 and signed "love forever Vonnie".Mr Siddeeq, a retired teacher who is now living in the mid-western city of Indianapolis, said he was shocked when he was contacted by the university.
"We have a system here in America where if something is for you and if they find it, it gets to you, that's beautiful," he told US TV station WTAE.
He and his girlfriend wrote to each other when he was studying science, he said.
They did eventually marry and have four children.
Romance was different then - with no computers, letter writing was the only way to stay in touch and remains more romantic than emails, he said.
He admitted to having mixed emotions about the letter as he and Vonnie are now divorced.
But he told Washington's Observer-Reporter paper that he was keen to read it as it was "a testament of the sincerity, interest and innocence of that time".
University officials said the letter was now on its way to him along with a T-shirt from the university.
"He said if he didn't get that package within the next 53 years, he would call to complain," university spokeswoman Christine Kindl told Reuters news agency.
Monday, 18 July 2011
Heavier seeds had a better chance of germinating in urban areas
Crepis sancta growing in urban areas produces heavy seeds that fall to the ground rather than lighter seeds that are dispersed by the wind.
Wind-blown seeds are less likely to germinate because most end up on concrete surfaces, scientists say.
The findings appear in Proceedings of the National Academy of Sciences.
Researchers from the Centre d'Ecologie Fonctionelle et Evolutive (CEFE), based in Montpellier, estimate that the change in the way the plant disperses its seeds has taken place in as little as five to 12 generations (five to 12 years).
Co-author Pierre-Oliver Cheptou said the team was surprised by the speed of the change.
"Logic would assume that this sort of evolutionary trait would develop more slowly, which is probably the case in less fragmented situations," he told BBC News.
"However, at the same time, it is consistent with the estimation we had for the trait in a fragmented urban situation."
The team collected seed samples from the weed, which grows on wasteland or next to roadside trees, from various locations around the French city.
In fragmented situations, the evolution towards lower dispersal leads to more isolated populations; increasing the risk of extinction
Dr Pierre-Olivier Cheptou,
They then grew them in a greenhouse to see what fraction of the resulting plants' seeds were of the light, wind-dispersible variety.
Compared with specimens taken from the countryside, the urban samples produced far fewer of these seeds.
The researchers said "dispersing" seeds had a 55% lower chance of germinating because the majority ended up on concrete surfaces.
The heavier seeds were at an evolutionary advantage because they would fall down into the patch of soil that had supported the previous generation of the plant.
They added that their findings supported "cost of dispersal" theories.
"When dispersal is passive (wind or water transport) and habitat choice is random, the probability of settling in a suitable site is positively dependent upon the frequency of suitable sites in the landscape," they wrote.
"Many empirical studies have reported a reduction in dispersal structures in organisms that live on islands, such as plants or insects."
Dr Cheptou said that their study showed the same also applied to plants in urban areas, where suitable soil was widely fragmented by buildings, pavements and roads.
He explained that such a strategy, while increasing the odds of survival for the next generation, could have drawbacks.
"We can hypothesise that in fragmented situations, the evolution towards lower dispersal leads to more isolated populations, increasing the risk of extinction."
Sunday, 17 July 2011
Innovative beehive fences have helped a community in Kenya to successfully protect crops from elephants, according to research.Scientists found the hives to be a very effective barrier; elephants turned away from them in 97% of their attempted raids.
Conservationists suggest that elephants' natural fear of bees could settle ongoing conflicts.
The hives' honey also produced additional profits for farmers.
Over the past 20 years, elephant numbers in Kenya have grown to around 7,500 and the population boost is widely heralded as a conservation success story.
However, conflict between elephants and humans, especially farmers, is an ongoing problem.
Elephants frequently "raid" farms searching for food such as ripe tomatoes, potatoes and maize.
To protect their livelihoods, some farmers have resorted to extreme measures including poisoning and shooting elephants.
Previous research into natural deterrents showed that elephants avoided African honey bees.In 2009, experts from the University of Oxford, UK, and the charity Save the Elephants set up a trial project to test whether beehives could prevent conflict on farmland boundaries.
After two years of observations, the full results of the trial have now been published in the African Journal of Ecology.
"Finding a way to use live beehives was the next logical step in finding a socially and ecologically sensitive way of taking advantage of elephants' natural avoidance behaviour to bees to protect farmers' crops," said Dr Lucy King, the University of Oxford biologist who led the study.
"It was very exciting to see that our theoretical work has been converted into a practical application," she said.
AFRICAN BEE FACTS
- Bees cannot sting through elephant hide, but they can and do sting around elephants' eyes and inside trunks
- The bees in Kenya (Apis mellifera scutellata) are small with short tongues and swarm frequently
- African honey bees were crossed with European honey bees in South America and are known as "killer bees" because of their increased aggression
In 32 attempted raids over three crop seasons, only one bull elephant managed to penetrate the novel defences.The beehives were suspended on wires between posts with a flat thatched roof above to protect from the sun in the traditional Kenyan style.
The team created a boundaries for 17 farms, incorporating 170 beehives into 1,700m of fencing.
"The interlinked beehive fences not only stopped elephants from raiding our study farms but the farmers profited from selling honey to supplement their low incomes," Dr King explained.
"The honey production and consequent income has really incentivised the farmers to maintain the fences."
Conservationists now hope to roll out the scheme to other farming communities.
Saturday, 16 July 2011
The International Whaling Commission's (IWC) annual meeting has closed after a tense final day when relations between opposing blocs came close to collapse.Latin American nations attempted to force a vote on a proposal to create a whale sanctuary in the South Atlantic.
Pro-whaling countries walked out, but eventually it was decided to shelve any vote until next year's meeting.
Environment groups said the delays and wrangling meant important issues for whale conservation were neglected.
But a number of nations pledged new funding for research on small cetaceans, some of which are severely threatened.
Earlier in the meeting, governments agreed new regulations designed to prevent "cash for votes" scandals that have plagued the IWC in the past, and passed a resolution censuring the Sea Shepherd Conservation Society for putting safety at risk during its annual missions to counter Japanese whalers in the Southern Ocean.
But the sanctuary issue threatened to derail the entire session.
"Whale species and populations from the Southern Atlantic oceanic basin were amongst the ones that suffered the most due to commercial whaling on a large scale," Roxana Schteinbarg, from the Argentina-based Institute for the Conservation of Whales, told delegates.
"Fifty-four species live in the waters where the sanctuary is proposed - it is therefore appropriate that the protection of these species in the Southern Ocean Sanctuary be extended and complemented in the reproduction areas in the Atlantic Southern basin."The 14-strong Buenos Aires bloc of nations knew it did not command the three-quarters majority needed to win, but remained determined to put it to the test.
"We didn't come here to win the sanctuary on the vote, but we wanted to put it to a vote - we believe our conservation agenda cannot be put forward, be stressed, be highlighted, be defended in some issues without a vote," said Brazil's commissioner Marcus Henrique Paranagua.
"Why not vote on things that are controversial?"
Voting with feet
The pro-whaling bloc said this could herald a return to the fractious days of the past, and walked out in an attempt to bring the meeting below the quorum needed for votes to count.
"We fear that the fact of voting will probably damage the very good atmosphere we have established, and might trigger a landslide of many votes for next year which might disrupt the progress we have made," said Japan's alternate (or deputy) commissioner Joji Morishita.
"This was not a hostile move to the Latin American countries - our effort is to try to save this organisation, and it turned out ok."
The good atmosphere, he added, had survived a "very difficult day".
Critics, however, said the pro-whaling countries had tried to hold the commission to ransom by their walkout.
Explosive meeting The compromise eventually hammered out, after private discussions lasting nearly nine hours, asks countries to strive to reach consensus during the coming year.
If that proves impossible, next year's meeting will start with a vote on the South Atlantic Sanctuary.
That could prove a particular concern for the US, which will be aiming at that meeting, in Panama, to secure renewed quotas for its indigenous hunters.
US commissioner Monica Medina agreed the potential vote "put a hand-grenade" under next year's meeting.
"I'm more than a little concerned - we've made good progress on improving the IWC's governance and that's a good thing," she said.
"But as long as we choose to continue fighting, all of the IWC's members will lose; and the world's whales deserve better."
The US played a leading role in the two-year "peace process" that attempted to build a major compromise deal between the various parties, and which collapsed at last year's meeting.
Missing in action Huge delays during the four days of talks meant that many items on the agenda pertinent to the health of whales and other cetaceans did not get discussed.
How to prevent whales from being killed by collisions with ships, how to reduce floating debris and how to tackle the growth of noise in the oceans were among the issues that received no discussion."Acrimony is often the enemy of conservation - in this case, it meant that a critical meeting on whales failed to address the greatest threats they face," said Wendy Elliott, head of environment group WWF's delegation.
"Several whale and dolphin species are in crisis - teetering on the brink of extinction - and conservation must be front and foremost at next year's IWC meeting, for the sake of the whales and the commission."
The research programmes of the cash-strapped commission received something of a boost with France, Italy and several non-governmental groups pledging a total of about £80,000 ($130,000) for small cetaceans, which include the critically endangered Mexican vaquita.
Friday, 15 July 2011
Westerners could be genetically programmed to consume fatty foods and alcohol more than those from the east, researchers have claimed.Scientists at the University of Aberdeen say a genetic switch - DNA which turns genes on or off within cells - regulates appetite and thirst.
The study suggests it is also linked to depression.
Dr Alasdair MacKenzie conceded it would not stop those moving to the west adapting to its lifestyle.
Obesity levels have risen sharply in many Western countries since the 1970s.
Dr MacKenzie, who lead the study team, told BBC Scotland they found Europeans were more inclined to consume fatty foods and alcohol - but that people from the East could end up with the same problems if adapting to a new culture.
Facts on calories
- In terms of nutrition, values are often given for the number of kilocalories in a food but referred to simply as calories
- The recommended daily calorie intake is 2,000 for women, and 2,500 for men (NHS Choices)
- Factors that influence energy intake include portion size, energy density and the number of meals, snacks and drinks consumed each day
Scientists at the university's Kosterlitz Centre said the switch controls the galanin gene.Dr MacKenzie said: "The switch controls the areas of the brain which allows us to select which foods we would like to eat and if it is turned on too strongly we are more likely to crave fatty foods and alcohol.
"The fact that the weaker switch is found more frequently in Asians compared to Europeans suggests they are less inclined to select such options.
"These results give us a glimpse into early European life where brewing and dairy produce were important sources of calories during the winter months.
"Thus, a preference for food with a higher fat and alcohol content would have been important for survival.
"The negative effects of fat and alcohol we see today would not have mattered so much then as life expectancies were between 30 to 40 years."
'Emotional state' He explained: "It is possible that during the winter individuals with the weaker switch may not have survived as well in Europe as those with the stronger switch and as a result those in the west have evolved to favour a high fat and alcohol rich diet."
Dr MacKenzie added: "Galanin is also produced in an area of the brain called the amygdala where it controls fear and anxiety.
"Thus, changing levels of galanin in the amygdala will have an effect on an individual's emotional state. Intriguingly, the switch was also active in the amygdala."
The study is being published in the Journal of Neuropsychopharmocology.
Wednesday, 13 July 2011
The catalogue that lists the most violent neighbourhoods in the Universe has been updated.The Fermi space telescope captures gamma rays - the highest-energy light in nature, which hints at the cosmos' most extreme conditions and processes.
The second Fermi catalogue represents a full two years of data, improving on the first edition's 11 months.
It lists 1,873 gamma-ray sources; some 589 remain unidentified and could represent entirely new cosmic objects.
Dave Thompson, a Nasa astrophysicist who co-led the catalogue's production, told BBC News that the effort was more than just an expanded list.
"The new catalogue is a new data set," he said. "We've reanalysed all the data, reduced our background, developed new methods of analysis. We're convinced that not only is this quantitatively a better catalogue - it's qualitatively a better catalogue."
It is also a snapshot from a slowly unfolding film of the Universe's most extreme environments.
"It's very important to understand that the gamma-ray sky is not static, it's changing all the time," explained Steven Ritz, deputy principal investigator for the Fermi mission's Large-Area Telescope.
"Our great advantage with this facility is that we're able to see the whole sky all the time; every three hours we've covered the whole sky, so there are interesting differences between the first year catalogue and the second and that speaks to the variability of the sky," he told BBC News.
Cosmic mysteries The greatest proportion of the sources - 1,095 of the 1,873 - is made up of what are known as active galactic nuclei, which are thought to be supermassive black holes at the centres of galaxies.
While they are known more for drawing material in, black holes can also help generate a jet of material and light; this jet, when pointed straight at the Earth, is known as a blazar.But the second-most common category that Fermi has spotted, comprising some 572 gamma-ray sources, is "unidentified".
That is, researchers have compared the objects' locations with those of other known sources of light, and found nothing that should be a gamma-ray emitter.
They are hundreds of cosmic mysteries waiting to be solved.
"My guess is that it's not just one class of sources, but there are many sources of types we already know about that we just haven't identified yet at other wavelengths," Dr Ritz said.
"And quite possibly new types of sources, which is what the whole thing is all about."
The Fermi team will continue to collect and refine their data, but the second catalogue represents the most comprehensive list that science has obtained of the Universe's most violent neighbourhoods - yet it remains to find out exactly what is going on in them.
"Our knowledge of the gamma-ray sky is very poor, so our knowledge of how gamma-ray sources tick - what makes them, how particles behave in them - is still fairly new," said Fermi project scientist Julie McEnery.
"It's part of the reason that the gamma-ray astronomy field is so exciting - because it's so fresh. We've been looking at the 'optical' sky since the Babylonians but the gamma-ray sky is definitely a 20th and 21st Century experience."
Tuesday, 12 July 2011
Snails are able to survive intact after being eaten by birds, according to scientists.Japanese white-eyes on the island of Hahajima, Japan feast on tiny land snails.
Researchers found that 15% of the snails eaten survived digestion and were found alive in the birds' droppings.
This evidence suggests that bird predation could be a key factor in how snail populations spread.
It is well known that plant seeds are dispersed by birds that eat fruit.
But in findings published in the Journal of Biogeography, researchers from Tohoku University, Japan investigated whether invertebrates could also spread in this way.
Previous research has shown that pond snails can survive being eaten by fish but the same was not known for land snails.
Studies of the diets of birds on the island of Hahajima identified the Japanese white-eye's preference for the tiny land snail Tornatellides boeningi.
In the lab scientists fed the birds with the snails to find out whether any survived the digestive process.
"We were surprised that a high rate, about 15 percent, of snails were still alive after passing through the gut of [the] birds," explained researcher Shinichiro Wada.
They also studied the genetic differences of T. boeningi populations found across the island and discovered considerable variation.Rather than only mating with nearby snails, these results suggested that different populations made contact despite their geographical isolation.
"Biogeography of wingless terrestrial invertebrates, in particular snails, is often faced with mysterious long distance dispersal patterns that can only be explained by hand waving arguments involving birds' feet or guts or cyclones," said Mr Wada.
"This is the first study showing that birds can indeed transport a substantial [number of] micro land snails in their gut alive."
One snail in particular helped researchers identify how numerous snails could travel over distances via bird droppings.
"One of the snails fed to the bird gave birth to juveniles just after passing through the gut," Mr Wada told the BBC.
The main factor allowing the snails to survive being eaten is their small size, according to the scientists.
At an average of 2.5mm the micro snails fared much better than larger species in previous studies whose shells were severely damaged when eaten by birds.
Mr Wada and his colleagues said further study is required to find out whether the tiny snails have other adaptations that allow them to survive.
Hahajima lies 1000km south of Tokyo in the Bonin Islands archipelago, known as the Ogasawara Group in Japan.
The islands were recently added to the UNESCO World Heritage List "for the wealth of their ecosystems which reflect a wide range of evolutionary processes".
Monday, 11 July 2011
The maternal ancestors of modern polar bears were from Ireland, according to a DNA study of ancient brown bear bones.Scientists in the UK, Ireland and the US analysed the teeth and skeletons of 17 brown bears that were found at eight cave sites across Ireland.
The new research has been reported in the latest edition of Current Biology.
Previously, it was believed that today's polar bears were most closely related to brown bears living on islands off the coast of Alaska.
However, analysis of mitochondrial DNA - which is passed from mother to child - has shown the extinct Irish brown bears are the ancestors of all today's polar bears, the scientists said.
Their work provides evidence of the two species mating opportunistically during the past 100,000 years or more.
Dr Ceiridwen Edwards Oxford University
Hybridisation has been recorded recently in the wild where grizzly bears have encroached on polar bear territories.The bears split from a common ancestor to become separate species between two million to 400,000 years ago.
However, just before or during the last Ice Age the two species came together and polar bears mated with female Irish brown bears, the scientists said.
The maternal lineage can still be traced to all polar bears today, they added.
Prof Daniel Bradley, of Trinity College Dublin (TCD) and Dr Ceiridwen Edwards, formerly of TCD and now at Oxford University, collaborated with Prof Beth Shapiro, of Pennsylvania State University, in the study.
Previously, Dr Edwards attempted to carry out DNA analysis of a sample taken from bones of a polar bear washed into caves in north west Scotland 18,000 years ago.
However, DNA had not survived in the remains from the Bone Caves at Inchnadamph in Sutherland.
'Environmental stresses' Brown bear bones have been found across Ireland, with some of the best preserved examples recovered by cavers at Poll na mBear - Cave of the Bears - in County Leitrim, in May 1997.
Eoghan Lynch and Barry Keenan made the first finds, followed by later discoveries by other speleologists.
Bear fact file
- Caves in County Leitrim were named Poll na mBear following the discoveries made by cavers in 1997
- According to the World Association of Zoos and Aquariums (WAZA) there were 200 polar bears registered in zoos worldwide in 2008
- Figures from the same year estimated that there might be 20,000 to 25,000 polar bears in the wild
An adult bear's skull with the teeth still in place and the bones of young bears were among the finds made.These have since been dated and are the last recorded bears in Ireland.
The scientists who carried out the DNA analysis said the caves' constant and cool temperatures protected genetic material within the bones.
Dr Edwards, the research paper's lead author, sequenced the mitochondrial DNA from different time depths and from bones recovered from the eight sites.
She found that the older bears in Ireland - from between 43,000 and 38,000 years ago and before the last Ice Age arrived - had the same genetic signature as brown bears living today in eastern Europe.
But DNA from bears that roamed Ireland in cooler times, 38,000 to 10,000 years ago, have sequences that are the closest match yet to modern polar bears.
Bone isotope analysis revealed that despite the maternal genetic link, the Irish ice bears did not share the polar bears' marine diet.
Prof Bradley said ancient samples offered a means of going back in time and measuring the movement of species in response to past climate change.
Dr Edwards added: "It's amazing to think that Irish brown bears are the ancestors of the modern maternal polar bear lineage.
"As the hybridisation between the two species occurred at a time when their home ranges overlapped, most likely during environmental stress, this has implications for polar bears in today's climate."
Prof Shapiro said the results of their research pointed to the bears hybridizing opportunistically throughout the past 100,000 years and probably longer.
She said: "While brown bears and polar bears are hybridizing today, our results suggest that a recent hybridisation led to the capture of a mitochondrial DNA sequence that was present in the population of brown bears that were living in Ireland before the peak of the last ice age.
"That mitochondrial sequence replaced the previous sequence across the entire polar bear population."
Previously it was thought modern polar bears were most closely related to brown bears living on the islands of Admiralty, Baranof and Chichagof in Alaska's Alexander archipelago.
Scottish site What are believed to be the only polar bear remains to have been found in Britain were in caves in Inchnadamph in Sutherland.
The bear's skull was found in 1927 and is held in the collections of the National Museum of Scotland.
An almost complete skeleton of another bear was recovered after years of work from the same Scottish site and later confirmed as that of a male brown bear.
The first pieces were discovered in 1995 by cavers exploring a network of caves.
But it was only in 2008 that Edinburgh-based caving club, Grampian Speleological Group, reached some of the final fragments.