(Image: Beso Gulashvili/Georgian Prime Minister's Press Service/EPA)
No you're not seeing things, that really is a hippo strolling down the road. After a major flood in Tbilisi, Georgia, on Sunday, which killed 12 people, several parts of the city zoo were destroyed, allowing animals to escape and take to the streets. Three zoo workers were among the dead.
The hippo was later shot with a tranquiliser dart while several other runaways were killed because of safety concerns, including six wolves, a boar, a tiger, a lion and a hyena.
City authorities were on the lookout for 32 predators. Many monkeys and a few lions were reported missing.
(Image: Beso Gulashvili/Georgian Prime Minister's Press Service/EPA)
A bear was spotted balancing on a windowsill (see picture, above). It was among eight bears that took to the streets after their enclosure was demolished. Rescuers in an inflatable boat gathered below to try to help the animal.
Residents were asked not to leave their homes, but there have been no reports of animal attacks so far. Police have been using helicopters, as well as searching the city on foot, to hunt down the escapees.
The flood occurred after strong winds and heavy rain hit the city, causing the Vere river to overflow. Models are predicting that extreme floods will increase dramatically in the coming decades because of climate change.
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They're two of the world's most loved animals - but there's little love between them.
Jon Aars of the Norwegian Polar Institute and his colleagues have made the first ever observations of polar bears eating white-beaked dolphins that had ventured too far north – in fact, they saw this happen several times last year.
The first incident was in late April 2014. Collecting data in Svalbard, Norway, Aars's team stumbled across a bear with two dead white-beaked dolphins, a species no one had ever seen the bears preying upon before.
"We think the bear killed them, [using] a similar technique as killing seals," says Aars. He thinks it probably caught the two dolphins when, trapped below the sea ice, they found a small hole and surfaced for air.
The bear, pictured below, had already eaten most of the first dolphin but couldn't finish all of its catch in one sitting. So it made use of the natural freezer, storing a second dolphin – still largely intact – under the snow for a later snack, presumably.
(Image: Jon Aars/Norwegian Polar Institute)
Hiding leftover food is a rare behaviour in polar bears. "We think he caught the second dolphin because he could, and then had extra food later," says Aars.
Subsequently, the team came across at least five other polar bears feeding on dead dolphins in the same area.
"We were surprised as dolphins have not been reported in that area before," says Aars. The explanation could be that the Svalbard waters were unusually warm at the time, and that a pod of dolphins had become trapped there when strong northerly winds had pushed them out of open water and in among the ice.
Ian Stirling of the University of Alberta in Canada is not surprised that the bears decided to feast on dolphin meat: polar bears are known to be opportunistic predators, and have been recorded eating many different animals.
"They will eat any marine mammal given a chance," he says. "The bigger surprise was that the dolphins were entrapped before they could migrate south for the winter."
As the climate warms, Stirling believes the sight of polar bears tucking into weird meals could become more common. Polar bears are "willing to take and use anything possible when available", he says.
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"Animal notes" and "wet hair" were the terms used to describe 170-year-old champagne hauled up from the bottom of the Baltic Sea in 2010. We now have chemical confirmation that the wine had aged well, but the mystery over how it got there is even murkier.
When the 163 bottles were recovered from 50 metres beneath the waves, seals on the corks showed that the wine had come from champagne houses Veuve Clicquot, Ponsardin, Heidsieck and Juglar (renamed Jacquesson & Fils in 1829). They were estimated to be between 170 and 180 years old.
Three of the Veuve Clicquot bottles were tasted by oenologists – on first opening they described the champagne as "sometimes cheesy", with "animal notes" and elements of "wet hair".
Swirling the champagne around in a glass to oxygenate it softened the flavours, which were then deemed to be grilled, spicy, smoky and leathery with fruity and floral notes.
Philippe Jeandet of the University of Reims Champagne-Ardenne, France, and his colleagues later got their hands on 2-millilitre samples from each bottle, which they ran through a detailed chemical analysis. This showed that the wine had been aged in wooden barrels, probably for six to eight months. That's consistent with documents left behind by Madame Clicquot, and different from the vineyard's modern practice of making its champagne in steel containers.
Mysterious destination
Traces of copper and iron came either from iron nails in the wooden barrels or iron instruments used during the winemaking, but did not spoil the wine.
The location of the bottles suggested they were on their way from Germany to Russia when they sank, sometime during the early 1800s. Russians at the time liked their bubbly very sweet – Madame Clicquot's notes mention that it was common practice in Russia to have a small bowl of sugar on the table to spoon into their wine. To cater to this market Clicquot made special extra-sweet batches for them.
So, if the Baltic bottles had been intended for Russia, they should have contained extra sugar. Jeandet and his colleagues found that while they were sweeter than modern bottles, they were nowhere near sweet enough for that market. They think they must have been destined for German tables, but admit that makes it difficult to explain why their ship was sailing through the northern Baltic.
"Overall, our analysis confirms that this champagne has kept the intrinsic characteristics of what a champagne is," says Jeandet. "This is fantastic, to observe that after 200 years of ageing at bottom of the sea."
Expensive taste
The conditions that the bottles were preserved in – complete darkness and a constant temperature between 2 ºC and 4 ºC – were ideal for wine ageing, he adds.
"Considering that these champagnes had been aged underwater for 170 years, they were amazingly well preserved," says Patrick McGovern, who studies the history of food and alcohol production at the University of Pennsylvania in Philadelphia. "[They are] testimony to human innovation in producing fermented beverages, which were central to human cultures around the world."
To commemorate the find, last year Veuve Clicquot sank 300 bottles and 50 magnums of champagne near where the 170-year-old bottles were found, inside a specially designed cage.
Jeandet says the experiment is mostly a marketing ploy. "I'm sure it will not change the taste of the wine but people will be proud to put it on their table and say, 'ho! You know this bottle has spent six years under the sea'. I know there are a lot of people ready to pay a lot of money for these bottles."
The 170-year-old champagne bottles are some of the oldest ever to have been tasted. In 2009, Perrier-Jouet opened an 1825 vintage from its cellars: at the time of tasting it was 184 years old and still tasted fine, with notes of truffles and caramel.
Correction, 21 April 2015:When this article was first published on 20 April 2015, the title prematurely aged the Champagne by a century. This has now been corrected.
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What if we transformed carbon dioxide from being a waste product into being a huge battery to help even out our energy supply? We could make carbon storage pay off, while solving problems of intermittent energy supply from renewables.
So say Tom Buscheck from the Lawrence Livermore National Laboratory in California and his colleagues who presented a design for this type of energy storage at the European Geosciences Union general assembly last week in Vienna, Austria.
Their design would be able to store the excess energy produced by renewable and conventional power sources when demand is low and, at the same time, lock up the major cause of global warming – carbon dioxide.
Carbon capture and storage has been slow to develop, in part because it is an extra cost for energy producers that provides little direct pay-off. "There's no business case to do it," says Jim Underschultz from the University of Queensland in Australia.
"CCS hasn't been utilised because no one has come up with a viable use for that storage," says Buscheck. But if stored CO2 could be used to hold surplus energy, it may give such technology the economic boost it needs.
"The only way you can decarbonise the fossil-fuel energy systems is if you can devise an approach where the economics makes sense," says Buscheck, who thinks their design, which is funded by the Geothermal Technologies Office at the US Department of Energy, does just that.
Supercritical storage
Buscheck's team proposes storing that excess energy in two forms: pressure and heat. Excess electricity would power a pump that injects supercritical CO2 – a hybrid state of liquid and gas – into underground brine in sedimentary rocks between 1 and 5 kilometres below the surface. Supercritical CO2 can drive turbines much more efficiently than steam and can take a lot of squeezing and heating – improving its capacity to store energy.
Another set of pipes tap into the brine in the sedimentary rocks. As the CO2 is pumped in, it will displace some brine, which is collected at the surface. Surplus energy can also be used to heat the brine and circulate it down into the deep rocks, which are able to store the heat effectively.
When the heated brine comes into contact with the CO2, it causes it to expand, thereby increasing the pressure of the stored CO2. The heat energy can be gathered by allowing the CO2 to depressurise, spinning supercritical CO2 turbines, which are 50 per cent more efficient than the steam equivalent. The team's modelling suggests that the system could regather up to 96 per cent of the heat stored.
Their approach could help solve a major problem with renewables: intermittent power. Solar and wind can fail to produce power when there is high demand. Similarly, sometimes they produce plenty of energy when demand is lower, and in this case, sources like nuclear, coal and older gas power stations can produce energy at a loss, or simply waste the heat they produce, never turning it into electricity.
The massive batteries that would be required to store the excess are still expensive and not very effective. Storing the energy by using it to pump water uphill – a current state of the art – can also waste a quarter of the energy in the process.
Getting bigger and better
"There is no doubt in my mind that we need to consider hybrid technologies of the sort proposed here," says Peter Cook from the University of Melbourne, Australia. He says the proposal takes a lot of existing ideas and integrates them in a new way, meaning that most of the technology is already proven.
But while this could contribute to reducing atmospheric carbon dioxide, it is unlikely to become a major carbon sink, says Cook.
One site could only store about 8 million tonnes of CO2 each year for 30 years – about the same amount as produced in one big coal-fired power station, says Buscheck, whose group is now looking for power companies to partner with on a pilot project.
Whether it is possible to scale-up the design remains to be seen, say Cook and Undershultz. Given its complexity, Undershultz says that costs and inefficiencies could add up as they scale it up. And Stuart Haszeldine from the University of Edinburgh, UK, says it would require a really good knowledge of geology to ensure carbon is sealed and does not escape.
Correction 21 April 2015:When this article was first published on 20 April 2015, the depth at which supercritical CO2 would be stored was wrong. This has now been corrected.
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We may owe our survival and complexity to a stowaway virus that springs to life in the very first cells of human embryos. Not only does the virus seem to protect embryos from other viruses, but it also assists genes when the groundwork is under way for the body plan of a new human.
The finding backs the controversial idea that viruses which took up residence in our DNA millions of years ago may be playing the role of puppet master, quietly influencing our existence and evolution. "We are creatures controlled by viruses," says Luis Villarreal of the University of California at Irvine.
Retroviruses insert their genetic material into the cells of their human or animal host. At first, this causes disease and death. Over time, however, the host evolves resistance to the virus, allowing any DNA that has embedded itself into sperm or egg cells to be passed down to the next generation. The virus is now known as an endogenous retrovirus or ERV – a permanent fixture in the host's genome.
Silent protector
About 9 per cent of our genome is thought to have come about this way. Until recently, these viral relics were largely dismissed as inactive "junk" that ceased to have any impact on their host many thousands of years ago. The discovery that HERVK, the most recent ERV to make itself at home in our DNA – probably around 200,000 years ago – is active in human embryos challenges that notion.
Joanna Wysocka and her colleagues at Stanford University in California made the unexpected find while they were analysing gene activity in 3-day-old human embryos, which are bundles of eight cells. Besides DNA from the parents, they found genetic material from HERVK. "The cells were full of viral protein products, some of which had assembled to form viral-like particles," says Wysocka.
Further experiments revealed that the virus appears to produce a protein that prevents other viruses penetrating the embryo, suggesting it protects the embryo from dangerous circulating viruses, such as influenza. It also seems to play a crucial role in the genetic activity of the embryonic cells, helping to genetic instructions to the cellular protein factories.
Biological dark matter
Tantalisingly, the stowaway virus might even provide clues to what makes us different from chimpanzees and other non-human primates. Some researchers have previously argued that ERVs may play a key role in how species diverge from each other, by activating different body plans and gene networks that may give one individual an edge over other members of the species.
Wysocka's work backs up this idea, says Patrick Forterre of the Pasteur Institute in Paris. "It shows that the protein products of a relatively 'recent' retrovirus integration are present very early on in the embryo, and could be involved in some critical developmental programmes." The observation that ERVs could also protect the embryo against infection also makes a lot of sense, he says Forterre. "It's as if retroviruses are competing with each other via their human host."
Despite being ubiquitous, viruses are often called the dark matter of biology as their influence frequently goes unnoticed. If DNA is a jungle, then the viruses are the animals and plants that live and adapt within it, says Villarreal, who in 2001 showed that the presence of a viral gene is essential for the formation of the human placenta. "DNA is the habitat, and the viruses are the inhabitants," he says. The most influential viruses are those, like HERVK, that have inserted themselves permanently into our DNA and can be passed on to the next generation.
These viruses have the genetic tools to refashion the hosts' genes, influencing which are active and when, and with which other genes they interact. This means they have the ability to reshape the physical characteristics of their hosts, says Villarreal. "It's a massive dynamic pool of colonising genomes."
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Video: Jugglers use mathematics to create new tricks
Circus Geeks: Beta Testing, Udderbelly at Southbank Centre, London, Tuesday 26 May 2015–Sunday 21 Jun 2015
In a gigantic upside-down purple cow – a tent that houses Udderbelly, an annual 8-week festival of comedy, circus and family entertainment on London's Southbank – Jon Udry stands on stage, empty-handed and perfectly still, juggling nothing whatsoever.
"This is very a useful technique," insists his partner-in-crime, Arron Sparks. You'll see when we come to do three-ball patterns later on."
This impromptu juggling class from the company Circus Geeks is probably not the most useful I've ever seen, but it promises to be the funniest. Their Beta Testing is a juggling show, TED talk and Royal Society lecture, rolled into one, and between the gags it does actually deliver on its promise, revealing the science and mathematics underpinning the modern juggling scene.
Juggling has probably been around since a bunch of primates let go of their branches and wondered what to do with their hands. And yet this venerable entertainment is being transformed out of all recognition by recent technology.
Online video has made a huge difference: "When I started," Sparks says, "there were bootleg VHS cassette tapes going round of all the old Soviet jugglers performing their classic 7-minute routines. It was all you ever saw of them, and we'd pass the tapes from hand to hand as we all tried to replicate this incredibly hard juggling. Now, thanks to the internet, moves can spread much more easily. You never come across just one video: inevitably seven kids have already posted their own versions and explorations of what you've just seen. It's probably a golden era of juggling at the moment."
Write and remember
Another key technology is notation. Bizarrely, for an activity so mathematical and so rhythmical, no one seems to have even proposed that routines should be written down before the juggler Dave Storer started noodling around with musical notation in 1978.
Three years later the American cryptographer Claude Shannon (widely considered the father of information theory) began writing an article called "Scientific Aspects of Juggling" for Scientific American, but he never finished it.
A coherent and simple way to note down and communicate juggling routines was finally discovered in 1985, not once but twice. Undergraduates Bruce Tiemann and Bengt Magnusson at the California Institute of Technology turned some notes by Paul Klimek of the University of California, Santa Cruz, into a working system they called Siteswap. At the same time in Cambridge, UK, mathematicians Mike Day, Colin Wright, and Adam Chalcraft hit upon an identical scheme.
Siteswap is a way of transcribing juggling patterns in numbers. "Things get interesting when you combine new numbers together," Sparks says. "The number 531, for example, describes a pattern where one ball is being re-thrown every five beats and one ball is being re-thrown every three beats and one ball is being thrown every one beat. And we can combine all these different techniques to create new juggling patterns."
Give me a 63141
Novel patterns have been discovered just by experimenting with the notation. Edward Carstens of the University of Missouri in Columbia has developed a version of Siteswap called MHN (multiple hand notation), which codifies tricks performed by any number of jugglers in unison.
"It's a really easy way to communicate juggling patterns," Sparks enthuses. "You can say to someone across the other side of the world, 'Can you do 63141 in flats with the juggling clubs?' and they can understand you straight away."
The arrival of Siteswap notation saw juggling flourish as a mathematical and physical pastime in colleges and universities worldwide. The wonder is that no one thought of it before.
Today the ability to codify, communicate and repeat human movements is an essential tool in the entertainment industry: games, films and TV all rely on it. But as this timeline on figuring out how we move reveals, the way we move has proved the very devil to write down.
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If there's one thing we have in common with these crabs, it's our keen sense of fashion. Many of us love to don new clothes, wear jewellery or get tattoos and piercings.
So it is with the decorator crabs. About three-quarters of over 900 species of crab in the family Majoidea decorate themselves, making them perhaps nature's most fashion-conscious animal.
Although not the only animals known to decorate themselves, the crabs are the most well-researched group, according to a study reviewing such behaviours.
They improvise accessories using whatever is around, grabbing items such as seaweed, corals and sponges, and sticking them on their shells. Everything stays in place thanks to the hooked hairs, called setae, which line their shells and act like Velcro.
Blending in
But while we adorn ourselves to be noticed, crabs do it for the opposite reason: the decorations often provide camouflage against predators like fish and octopuses. Against the proper background, a decorator crab can blend in perfectly.
"The nice thing about being a decorator is that wherever you go, you can pull off the old decoration and stick on something new and quickly adapt yourself to whatever environment surrounds you," says John J. Stachowicz, an ecologist at the University of California, Davis. "If you're a slow-moving, roving animal, being able to quickly adopt the coloration or background of wherever you are is likely very adaptive."
For instance, the yellowline arrow crab (Stenorhynchus seticornis) tears a piece of seaweed in its claws and then chews it to make it rougher and more likely to catch on its shell. It backs up the camouflage by remaining still during the day and freezing when predators approach.
Repellent dress sense
Other decorator crabs are picky: any old outfit won't do. They go for materials that are chemically noxious or otherwise repugnant to predators.
"They are selecting decorations that make them toxic or bad to eat," says Stachowicz.
The long-legged spider crab (Macropodia rostrata) and the longnose spider crab (Libinia dubia), for example, cover their shells with toxic seaweed. Stachowicz says you can trick these crabs into donning just about anything if you extract a chemical that fish find repellent from their preferred seaweed and paint it on to materials that they normally don't use.
Yet others adorn themselves with stinging sea anemones. Predators might be able to detect the crabs, but will avoid attacking them.
Like all crustaceans, decorator crabs must shed their shells in order to grow, but they will often recycle their decorations after they moult. Carefully removing all the seaweed, anemones, sponges and other accessories from their old shell, they attach them to the new one when it hardens.
But some species outgrow the urge to accessorise altogether, possibly because they have fewer predators once they reach a certain size.
Journal reference: Royal Society Biology Letters, DOI: 10.1098/rsbl.2015.0325
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Would make some epic calamari (Image: New Zealand Ministry of Fisheries)
You wouldn't want to get caught between these two sea monsters. This pair of massive deep-water foes are waging war in Antarctic waters, and it's eat or be eaten.
Given it weighs up to half a tonne and measures more than 2.5 metres in length without taking into account its long tentacles, we know surprisingly little about the colossal squid.
It was first identified in 1925 based on remains found in the stomach of a sperm whale. But other than it being whale food and living in the deep seas of Antarctica, "literally nothing is known about the colossal squid," says Vladimir Laptikhovsky of the Centre for Environment, Fisheries and Aquaculture Science in Suffolk, UK.
Now Laptikhovsky and his team have revealed one of the squid's secrets – they seem to have a taste for the Antarctic toothfish, another deep-water giant.
The squid's nemesis (Image: Rob Robbins/USAP)
Like the colossal squid, the Antarctic toothfish is a predator that usually lives in eternal darkness, somewhere between 1 and 2 kilometres below the ocean surface. They can grow up to 2 metres in length and can live to be 40 years old. "It is a voracious predator that feeds on different fish, squid and shrimps," says Laptikhovsky.
Colossal squid have occasionally been observed attacking and feeding on Antarctic toothfish as they were being hauled in by fishers. Now Laptikhovsky and his colleagues have shown that, far from this being a rare occurrence, colossal squid regularly attack Antarctic toothfish.
They examined more than 8000 toothfish caught by fishing vessels between 2011 and 2014. The team found that 71 toothfish showed clear signs of colossal squid attack – scratches made by the squid's suckers and hooks, and deeper wounds gouged by its beak.
"You should see the other guy" (Image: A.V.Remeslo)
"Taking into account the size of adult squid, the toothfish probably is its most common prey species, because no other deep-sea fish of similar size are available around the Antarctic," says Laptikhovsky.
But the toothfish do seem to get their revenge. The team also found the remains of colossal squid arms, tentacles, beaks and bodies inside the stomachs of 57 toothfish.
Because Antarctic toothfish are about half the size of an adult colossal squid, Laptikhovsky says they probably only attack juvenile, old or wounded squid.
Treat for a toothfish (Image: A.V.Remeslo)
"Prior to these findings, there was little solid evidence of what colossal squid might eat," says Kat Bolstad of the Auckland University of Technology in New Zealand.
She is also searching for clues about the squid's mysterious life. Over the past 11 years Bolstad has examined four large squid and several smaller specimens. "We actually have a set of colossal gut contents from a 2014 specimen that we are planning to analyse over the next couple of months, so that may also help us fill in a few puzzle pieces," she says.
Colossal and chewy
It is thanks to the colossal squid's deep-sea feud that we now know what these creatures taste like – Laptikhovsky once had the chance to sample a tentacle that was stuck to a toothfish after a failed attack.
"The piece of tentacle was boiled and I tried it without using any spice or sauce to get an impression of the taste," says Laptikhovsky. "It was okay, better than the widely fished jumbo squid. I would say it tasted like a shortfin squid, a bit chewier because of the size."
Journal reference: Journal of Natural History, DOI: 10.1080/00222933.2015.1040477
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Fly like the wind (Image: Christopher Ousdal/Alamy)
Moving silently through the air is not just for the birds. Wind farms inspired by the stealthy flight of owls could generate more energy without annoying those who live nearby, say researchers.
Turbines create emissions-free electricity by using the wind to turn propeller-like blades around a rotor. But conservationists are concerned about the effects of their noise on terrestrial and marine life, and people who live near turbines demand quiet operation too.
Now Nigel Peake of the University of Cambridge and his colleagues have turned to owls for inspiration. Owls are famously silent predators, able to surprise their prey thanks to sound-dampening wings.
Peake looked at two features that make their wings silent. Evenly spaced bristles along the width of the wings break up sound waves as an owl flies, preventing them from building up and producing noise. At the same time, a canopy of downy feathers reduces air pressure on the wings' surface, providing a dampening effect. "These features are absolutely unique to owls," says Peake.
Taking flight
Next, the team made its own wings by taking an aerofoil and adding a number of fins that trail across and off the edge of the surface. The fins replicate the owl's evenly spaced bristles, and also disrupt surface pressure on the aerofoil, reducing the sound waves it produces.
When the researchers tested the wings in a wind tunnel, they found that noise reduction worked best when the fins were close together, spaced 1 millimetre apart across the aerofoil.
The best-performing fins cut noise by a factor of 10 compared with finless aerofoils. The team will present the work at the American Institute of Aeronautics and Astronautics conference in Dallas, Texas, later this month.
As well as making them quieter, attaching fins to wind turbines might even help them to generate more energy.
"Many wind turbines are artificially braked so that they don't make too much noise," says Peake. With this technology, the turbines could run faster without getting louder. The fins do produce extra drag on wings, but more rapid spinning would outweigh any energy lost, says Peake. His team is now working with a turbine manufacturer to test the idea.
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Man's best friend may be a very old friend indeed. An analysis of a bone from a newly identified ancient wolf species suggests dogs may have split from wolves as early as 40,000 years ago – with or without being domesticated at the same time.
Exactly when dogs started to be domesticated and split from wolves is a matter of some controversy. Archaeological evidence analysing the shapes of canid skulls found near early human camps suggested it might have happened as far back as 35,000 years ago. DNA analysis, focusing on differences between living dog and wolf genomes, seemed to suggest they must have split much more recently – between 11,000 and 16,000 years ago.
Now Love Dalén from the Swedish Museum of Natural History in Stockholm and colleagues have sequenced the genome of a wolf that lived 35,000 years ago in Taimyr, northern Russia, according to carbon dating. This allowed them to recalibrate the molecular clock – the rate at which genetic differences accumulate over time – and better reconstruct the wolf-dog evolutionary tree.
They found that dogs and wolves must have split into two separate lineages 27,000 to 40,000 years ago, bringing the DNA and archaeological evidence into line with each other.
They also found that some northern latitude dog breeds, having split from wolves, then interbred with the now extinct Taimyr wolf, which could have helped them adapt to the challenging northern environment. These breeds include the husky, Greenland sledge dog and, to a lesser extent, the Chinese shar pei and Finnish spitz.
But although the findings back an early split of dogs from wolves, they don't tell us when the domestication of dogs started. "The present study does not rule out the possibility of a very early date indeed, but it does not rule the possibility of a much later date either," says Laurent Frantz from the University of Oxford.
Perhaps humans didn't domesticate dogs once the creatures had split away from wolves: the alternative possibility is that there was an early split between two types of wolves, and that dogs emerged much later on one of these lineages. "We do not yet know whether it infers an early divergence between two wolf populations or between wolves and dogs," says Frantz.
Dalén says a combination of genomic and morphological work on ancient wolf or dog specimens is needed before we have a conclusive date on the time of domestication.
Mietje Germonpre of the Royal Belgian Institute of Natural Sciences in Brussels was one of the researchers who did the skull-shape work that suggested an early date of domestication. She is excited by the new findings, and says she is already studying a lot more specimens that should help clarify the question.
"I find it interesting that early modern humans might have been so resourceful that they started making use of dogs already during the height of the last Ice Age," says Dalén.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2015.04.019
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A new study has discredited the theory that dyslexia is caused by visual problems. So what does cause the condition and how can it be treated?
What kind of visual problems are claimed to cause dyslexia? A huge variety. They include difficulties in merging information from both eyes, problems with glare from white pages or the text blurring or "dancing" on the page. A host of products claim to relieve this so-called visual stress, especially products that change the background colour of the page, such as tinted glasses and coloured overlays.
Others advise eye exercises that supposedly help people with dyslexia track words on the page. Despite lack of evidence that these approaches work, some people with dyslexia say they help – more than half of university students with dyslexia have used such products.
What are the new findings? That there's no evidence visual stress is linked with dyslexia. Nearly 6000 UK children aged between 7 and 9 had their reading abilities tested as well as performing a battery of visual tests. About 3 per cent of them had serious dyslexia, in line with the national average. But in the visual tests, the differences between the students with and without dyslexia were minimal. In two of the 11 tests, about 16 per cent of the children with dyslexia scored poorly, compared with 10 per cent for children with normal reading abilities. But that small difference could be caused by the fact that they read less, says author Alexandra Creavin of the University of Bristol, UK. And more importantly, the 16 per cent figure is so low, it can't be the main explanation for dyslexia.
So what does cause dyslexia? We don't know. Various ideas have been put forward to explain why some children of normal or above-average intelligence have difficulty learning to read, but none of these theories have become generally accepted. Brendan Barrett of the University of Bradford in the UK says it may be more helpful to regard the condition as an unexplained difficulty with reading that doesn't necessarily reflect someone's intelligence. Many in the field now prefer the term "reading impairment" to avoid the unproven claims about dyslexia. "The term has a lot of baggage," says Barrett.
But those affected by the condition may have been written off as stupid, so appreciate having dyslexia as their "diagnosis".
How should we be treating the condition? Evidence suggests that the best methods for helping people with dyslexia are the same as those that help anyone learn to read. The old-fashioned "phonics" method teaches individual letter sounds, then how to blend them together into words. People with dyslexia may just need a lot more of this kind of tuition than others. "But if you're spending time on eye exercises, that might be time not spent on phonics," says Creavin.
Who is pushing the coloured overlays? There's a whole industry based on the visual stress theory, selling not only glasses and overlays but also consultations that can cost hundreds of pounds. "Families are very keen to help their children," says Cathy Williams, who also took part in the study. "There's a belief that in order to do right by their children, they must get hold of these products."
But dyslexia charities also need to be more sceptical, says Williams. A survey last year found that six out of eight UK dyslexia organisations were promoting such products on their websites uncritically and some general health websites accept their value. In a review for the UK's College of Optometrists, Barrett found that coloured overlays were not supported by evidence. But he says he has seen enough people who find them helpful to keep an open mind.
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(Image: Brian van der Brug/Los Angeles Times via Getty Images)
This aerial photo shows part of Santa Barbara's coastline in California, after an estimated 21,000 gallons of oil spewed into the Pacific Ocean on Tuesday.
Taken on Wednesday, oil-soaked kelp darkened the water as efforts to mop up the spill continued.
The cause was a burst pipe, which leaked for 3 hours and released more than 100,000 gallons of oil in that time. Most of it remained on land, spreading across roughly 6.5 kilometres of beach, but enough leaked into the sea to form a 14-kilometre slick.
Many are concerned about the harm it will do to the area's wildlife, which includes whales and sea lions. Dead animals found so far include this oil-covered lobster.
(Image: David McNew/Getty Images)
The same area suffered a devastating spill in 1969, when a platform blowout released hundreds of thousands of gallons of oil into the sea, killing thousands of marine mammals and seabirds.
In the struggle to limit the damage this time, more than 300 people have been involved in clean-up efforts so far. Volunteers have been helping a crew of workers involved in cleaning the beach by raking and vacuuming up oil, and vessels have been deployed to remove oil from the sea surface.
(Image: ZUMA/REX_Shutterstock)
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Species:Gladicosa gulosa Habitat: Leaf litter of beech-maple forests in the east of the US and Canada
With a sound like a wad of money being quietly thumbed, it's hardly a Handel aria.
But for the purring wolf spider, it's music. For the first time, a spider has been recorded producing what appear to be audible courtship signals over and above pure vibrations.
"It's very quiet, but it's what you would hear if you were in the room with a courting spider," says George Uetz of the University of Cincinnati in Ohio, who discovered the purring wolf spider with colleague Alexander Sweger. "The sound is at a level that's audible by human hearing at about a metre away."
Many spider species rely heavily on vibrations to send signals to one another, by shaking leaves or strands of their webs, for example.
Thrum away
But the purring wolf spider is different. While using their pedipalps – the appendages next to their mouthparts – to vibrate dead leaves, they also create an audible thrumming sound. Click here to listen to the spider.
The discovery is a puzzle, as spiders aren't known to have anything equating to "ears".
To check that the "thrum" isn't a bog-standard vibration signal, Uetz and Sweger used a vibration detector called a laser Doppler vibrometer to detect the drumming of the spider and convert it into an audible "sound" output.
Then they used a standard microphone to pick up the audible sound produced at the same time. Comparing the two showed that the vibration and the thrumming sound were two separate emanations.
The pair also found that males produce the sound and only females respond to a played recording of the purr, suggesting that the purr is used in courtship.
"We have yet to see any evidence of any male-to-male communication in this species," says Uetz.
Sensitive spiders
The males only produce the sounds if they are standing on something that will vibrate, like a leaf, and females only respond when perched on a similar surface.
Uetz and Sweger think that the signal reaches the female by travelling as sound in air, which causes the leaves a female is standing on to vibrate.
"We think that's how she 'hears' the sound," says Sweger. "Spiders have very sensitive structures all over their bodies for detecting vibration, even at low levels, so we're working on the hypothesis that they detect a surface vibration induced by the airborne sound."
The purring spiders may help us better understand how communication by sound first evolved. "Animal acoustic signals may originally have evolved from vibration, and our findings suggest a possible mechanism," says Sweger.
The pair reported their findings today at the annual meeting of the Acoustical Society of America in Pittsburgh, Pennsylvania.
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"All I can say is wow, just freakin wow!" says Lisa-Ann Gershwin from Australian Marine Stinger Advisory Services in Launceston, Australia.
This river in Southern Tasmania seemed to come alive this week as a bloom of Noctiluca scintillans – a type of bioluminescent plankton, also known as "sea sparkle" – washed into the region.
When it's disturbed, the organism produces light in its cytoplasm, the gel-like substance inside its single cell.
As news of the bloom spread, hundreds of people came to see the spectacle, says Gershwin. "People turned out in droves, rolled up their pant legs and danced, ran, splashed, stomped, tiptoed, you name it, people played! It was incredible!"
But there is a dark side to this impromptu festival of light. "The displays are a sign of climate change," says Anthony Richardson from the CSIRO, Australia's national science agency in Brisbane.
Until 1994, Noctiluca had not been seen in Tasmania. But global warming has been strengthening the East Australian current, which pushes warm water south towards Tasmania. "As the Southern Ocean warms, it will be warm enough for Noctiluca to survive," says Richardson.
What's more, these particular plankton have more direct impacts too. "Noctiluca is a voracious feeder on diatoms, which is the food for krill in the Southern Ocean," says Gustaaf Hallegraeff from the University of Tasmania in Hobart. Dense blooms like this can therefore starve other organisms, he says. They can also kill fish through oxygen depletion and gill irritation.
"As wondrous and entertaining as Noctiluca is, it is also a species infamous for causing fish kills," says Gerhswin. But what the outcome will be from this particular bloom remains an unresolved question, adds Hallegraeff. "Blooms can disappear within days, leaving essentially no trace."
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A radical plan for transplanting a head onto someone else’s body is set to be announced. But is such ethically sensitive surgery even feasible?
IT'S heady stuff. The world's first attempt to transplant a human head will be launched this year at a surgical conference in the US. The move is a call to arms to get interested parties together to work towards the surgery.
The idea was first proposed in 2013 by Sergio Canavero of the Turin Advanced Neuromodulation Group in Italy. He wants to use the surgery to extend the lives of people whose muscles and nerves have degenerated or whose organs are riddled with cancer. Now he claims the major hurdles, such as fusing the spinal cord and preventing the body's immune system from rejecting the head, are surmountable, and the surgery could be ready as early as 2017.
Canavero plans to announce the project at the annual conference of the American Academy of Neurological and Orthopaedic Surgeons (AANOS) in Annapolis, Maryland, in June. Is society ready for such momentous surgery? And does the science even stand up?
The first attempt at a head transplant was carried out on a dog by Soviet surgeon Vladimir Demikhov in 1954. A puppy's head and forelegs were transplanted onto the back of a larger dog. Demikhov conducted several further attempts but the dogs only survived between two and six days.
The first successful head transplant, in which one head was replaced by another, was carried out in 1970. A team led by Robert White at Case Western Reserve University School of Medicine in Cleveland, Ohio, transplanted the head of one monkey onto the body of another. They didn't attempt to join the spinal cords, though, so the monkey couldn't move its body, but it was able to breathe with artificial assistance. The monkey lived for nine days until its immune system rejected the head. Although few head transplants have been carried out since, many of the surgical procedures involved have progressed. "I think we are now at a point when the technical aspects are all feasible," says Canavero.
This month, he published a summary of the technique he believes will allow doctors to transplant a head onto a new body (Surgical Neurology International, doi.org/2c7). It involves cooling the recipient's head and the donor body to extend the time their cells can survive without oxygen. The tissue around the neck is dissected and the major blood vessels are linked using tiny tubes, before the spinal cords of each person are cut. Cleanly severing the cords is key, says Canavero.
The recipient's head is then moved onto the donor body and the two ends of the spinal cord – which resemble two densely packed bundles of spaghetti – are fused together. To achieve this, Canavero intends to flush the area with a chemical called polyethylene glycol, and follow up with several hours of injections of the same stuff. Just like hot water makes dry spaghetti stick together, polyethylene glycol encourages the fat in cell membranes to mesh.
Next, the muscles and blood supply would be sutured and the recipient kept in a coma for three or four weeks to prevent movement. Implanted electrodes would provide regular electrical stimulation to the spinal cord, because research suggests this can strengthen new nerve connections.
When the recipient wakes up, Canavero predicts they would be able to move and feel their face and would speak with the same voice. He says that physiotherapy would enable the person to walk within a year. Several people have already volunteered to get a new body, he says.
The trickiest part will be getting the spinal cords to fuse. Polyethylene glycol has been shown to prompt the growth of spinal cord nerves in animals, and Canavero intends to use brain-dead organ donors to test the technique. However, others are sceptical that this would be enough. "There is no evidence that the connectivity of cord and brain would lead to useful sentient or motor function following head transplantation," says Richard Borgens, director of the Center for Paralysis Research at Purdue University in West Lafayette, Indiana.
If polyethylene glycol doesn't work, there are other options Canavero could try. Injecting stem cells or olfactory ensheathing cells – self-regenerating cells that connect the lining of the nose to the brain – into the spinal cord, or creating a bridge over the spinal gap using stomach membranes have shown promise in helping people walk again after spinal injury. Although unproven, Canavero says the chemical approach is the simplest and least invasive.
But what about the prospect of the immune system rejecting the alien tissue? Robert White's monkey died because its head was rejected by its new body. William Mathews, chairman of the AANOS, says he doesn't think this would be a major problem today. He says that because we can use drugs to manage the acceptance of large amounts of tissue, such as a leg or a combined heart and lung transplant, the immune response to a head transplant should be manageable. "The system we have for preventing immune rejection and the principles behind it are well established."
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The latest AI devices can't just gauge your mood from what you say and how you say it, they can work out the best way to respond to cheer you up
"BRIAN? How are you, Brian?" The voice is coming from a screen dominated by a vast blue cartoon eyeball, its pupil dilating in a way that makes it look both friendly and quizzical. Think HAL reimagined by Pixar.
This is EmoSPARK, and it is looking for its owner. Its camera searches its field of view for a face and, settling on mine, asks again if I am Brian. It sounds almost plaintive.
EmoSPARK's brain is a 90-millimetre Bluetooth and Wi-Fi-enabled cube. It senses its world through an internet connection, a microphone, a webcam and your smartphone. Using these, the cube can respond to commands to play any song in your digital library, make posts on Facebook and check for your friends' latest updates, stream a Netflix film, answer questions by pulling information from Wikipedia, and simply make conversation.
But its mission is more complex: EmoSPARK, say its creators, is dedicated to your happiness. To fulfil that, it tries to take your emotional pulse, adapting its personality to suit yours, seeking always to understand what makes you happy and unhappy.
The "Brian" in question is Brian Fitzpatrick, a founding investor in Emoshape, the company that makes EmoSPARK. He and the device's inventor, Patrick Levy Rosenthal, compare EmoSPARK's guiding principles to Isaac Asimov's laws of robotics. They are billing the cube as the world's first "emotional AI".
But EmoSPARK isn't the first robotic agent designed to learn from our emotions. There's Jibo the family robot and Pepper the robot companion. Even Amazon's Echo voice-activated controller might soon be able to recognise emotions.
The drive to give artificial intelligence an emotional dimension is down to necessity, says Rana el Kaliouby, founder of Affectiva, a Boston-based company that creates emotion-sensing algorithms. As everything around us, from phones to fridges, gets connected to the internet, we need a way to temper machine logic with something more human.
And when the user is immersed in a world that is as much computer as real life, a machine must learn some etiquette. For example, you shouldn't come home from a funeral to find your AI itching to tell you about the latest Facebook cat videos.
How can a machine be trained to understand emotions and act on them? When EmoSPARK's webcam finds my face, a red box flashes briefly on screen to indicate it has identified a face that isn't Brian's. Behind the scenes, it is also looking for deeper details.
EmoSPARK senses the user's emotional state with the help of an algorithm that maps 80 facial points to determine, among other things, whether he or she is smiling, frowning in anger or sneering in disgust. EmoSPARK also analyses the user's tone of voice, a long-established method of mood analysis.
Having sensed these details, EmoSPARK uses them to mirror your emotions. First, it creates an emotional profile of its owner based on the combination of facial and voice input. At the end of each day, it sends this information to EmoShape, which sends back a newly tailored emotional profile for that particular device. Through this feedback loop, Fitzpatrick says, the cube's personality changes ever so slightly every day.
Hard problems
Rosalind Picard at the Massachusetts Institute of Technology is sceptical that this can produce an accurate emotional profile. Picard, who designs facial and vocal analysis software to help computers interpret emotion, and co-founded Affectiva with el Kaliouby, says there's more to understanding moods than mapping points on the face. "What does it know about the context? How much data is it trained on? How is it being taught the true feelings of the person? These are still hard problems to solve."
The algorithm used by EmoSPARK isn't necessarily all that sophisticated. Coaxing it to register a user's smile requires a toothy grin in good lighting; real-world conditions, for most people, don't live up to that.
But maybe you don't need a million-dollar algorithm. One aspect of creating "emotional" AI requires neither hardware nor software: it's just a matter of exploiting what our brains do naturally. "We anthropomorphise everything," says Eleanor Sandry at Curtin University in Perth, Australia. Humans project intent and emotions on to anything from dolphins to Microsoft's paper clip. We can't help ourselves.
And EmoSPARK pulls out all the stops to put this tendency to work. To calibrate your cube, you undertake a ritual which ensures that only one person can be emotionally bound to it. "Are you the person I am to bond with?" is its first question. Although it will recognise other individuals in the same house or building, it only creates the emotional profile for its owner.
That doesn't mean it can't interact with anyone else. When someone who is not Brian taunts it, saying "I don't like you", EmoSPARK manifests its displeasure with a pulse of green light that shudders through the cube. "It's funny, I don't like you that much either," it responds. If EmoSPARK had been complimented, it would have glowed purple.
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Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world
Species: Malayan flying lemur (Galeopterus variegatus) Habitat: Rainforests and plantations of South-East Asia
Take one look at a flying lemur, or colugo, sitting in a tree and it brings to mind a scrawny kid forced to wear his big brother's hand-me-downs. Flaps of skin hang around its ankles and get in the way as it clambers awkwardly around the forest.
Once the colugo leaps into the air, though, everything changes. Its baggy folds transform into enormous wings as the animal sails gracefully through the canopy.
With their bark-patterned fur and nocturnal habits, spotting these animals, which are about the size of large squirrels, is tough. This didn't deter Yamato Tsuji of Kyoto University, Japan, and his colleagues, who spent four years in the jungles of Indonesia studying them.
Colugos spend their days curled up in cracks and crevices in the rainforest trees, only emerging to snack on young leaves at night. They are particular about which tree species they sleep in, Tsuji and his team found, and above all favour tall, isolated trees standing high above the canopy.
Here they can hide from predators, such as civets and pythons. But if spotted, the lack of surrounding vegetation makes for a quick and easy getaway. It also gives them a nice launch pad for their dusk departure to feeding trees lower down in the canopy.
These animals are not technically flying, of course, but neither are they lemurs, though they are related. They belong to a family called the Cynocephalidae. The Philippine and Malayan flying lemurs are the only two species in this very exclusive club.
They lack the opposable thumbs of their primate cousins, which partly explains their ungainly, frog-like climbing technique, says Tsuji.
But what they lack in ability on the branches they more than make up for in the air. Colugos are the largest of the gliding mammals, and with an arm span of 70 centimetres, this makes for impressive "wings". Stretching from fingertip to tail tip they are big as physically possible. Even their fingers are webbed to maximise the glider's surface area. This feat of natural engineering allows flying lemurs glide over 130 metres while losing only around 10 metres in height - on a par with flying squirrels and other gliding mammals. During the day, the flaps double up as a cosy shelter for baby colugos as they cling to their mother's belly.
When it comes to landing, colugos have class. Since gliding is little more than falling with style, you might think it would end in a dramatic landing. Not a bit of it. Colugos can adjust their aerodynamics to slow themselves down significantly. Just before landing they angle their body upwards to reduce speed, landing softly on all fours with pinpoint accuracy.
These easy gliders suffer from habitat loss and hunting, but luckily, at the moment their numbers seem to be holding up reasonably well.
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(Image: © Samuel Blanc / www.sblanc.com)
(Image: Jon Aars/Norwegian Polar Institute)
Love the, er, hair extensions (Image: Birgitte Wilms/Minden Pictures/Corbis)
Would make some epic calamari (Image: New Zealand Ministry of Fisheries)
The squid's nemesis (Image: Rob Robbins/USAP)
"You should see the other guy" (Image: A.V.Remeslo)
Treat for a toothfish (Image: A.V.Remeslo)
Fly like the wind (Image: Christopher Ousdal/Alamy)
(Image: Brian van der Brug/Los Angeles Times via Getty Images)
(Image: David McNew/Getty Images)
(Image: ZUMA/REX_Shutterstock)
to one another, by shaking leaves or strands of their webs, for example.
(Image: Jo Malcomson)
