A potato affected by P. infestans, the pathogen responsible for the Irish Potato Famine. The exact strain involved in the 1840s famine has now been identified for the first time. Image via USDA

For nearly 150 years, starting in the late 17th century, millions of people living in Ireland subsisted largely off one crop: the potato. Then, in 1845, farmers noticed that their potato plants’ leaves were covered in mysterious dark splotches. When they pulled potatoes from the ground, most were shrunken, mushy and inedible. The blight spread alarmingly quickly, cutting yields from that year’s harvest in half. By 1846, harvest from potato farms had dropped to one quarter of its original size.

The disease—along with a political system that required Ireland to export large amounts of corn, dairy and meat to England—led to widespread famine, and nearly all of the few potatoes available were eaten, causing shortages of seed potatoes that ensured starvation would continue for nearly a decade. Ultimately, over one million people died, and another million emigrated to escape the disaster, causing Ireland’s population to fall by roughly 25 percent; the island has still not reached its pre-famine population levels today.

At the time, the science behind the blight was poorly understood, and most believed it was caused by a fungus. During the twentieth century, scientists determined that it was caused by an oomycete (a fungus-like eukaryote) called Phytophthora infestans. However, without access to the 1840s-era specimens, they couldn’t identify exactly which strain of the organism was responsible.

Now, an international group of scientists has gone back and sampled the DNA of Irish potato leaves preserved in the collections of London’s Kew Gardens since 1847. In doing so, they discovered that a unique, previously unknown strain of P. infestans that they call HERB-1 caused the blight.

Irish potato leaves from 1847, the height of the famine, used as part of the study. Image via eLife/Kew Gardens

The researchers, from the Sainsbury Laboratory in the UK and the Max Planck Institutes in Germany, came to the finding as part of a project sequencing DNA from 11 different preserved historial samples and 15 modern ones to track the evolution of the pathogen over time, published today in the journal eLife [PDF].

Currently, P. infestans is distributed worldwide, with the vast majority comprised of the destructive strain US-1. Most of the other strains of P. infestans occur only in Mexico’s Toluca Valley, where wild potato varieties are indigenous, so scientists long believed that US-1 had been responsible for the 1840s famine.

But when the researchers extracted small pieces of intact DNA from the old dried-out potato leaves, originally collected from from Ireland, Great Britain, Europe and North America, and compared them with present-day P. infestans specimens, they found that the strain responsible for the famine differed slightly from today’s US-1.

Based on their analysis of the genetic variation between the two strains and the other historical samples, they suggest that sometime in 1842 or 1843, the ancestor of the HERB-1 strain of P. infestans made it out of Mexico to North America and then to Europe, perhaps contained within the potatoes that ships carried as food for their passengers. Soon, it spread across the world, triggering famine in Ireland, and persisting until the 1970s, when it died out and was largely replaced by the US-1 strain. The two strains likely split apart sometime soon after their common ancestor made it out of Mexico.

The study is the first time that the genetics of a plant pathogen have been analyzed by extracting DNA from dried plant samples, opening up the possibility that researchers can study other plant diseases based on the historical collections of botanical gardens and herbaria around the world. Better understanding the evolution of plant diseases over time, the team says, could be instrumental in figuring out ways to breed more robust plant varieties that are resistant to the pathogens that infect plants today.

The rare coealacanth’s genome is slowly evolving—and contrary to prior speculation, it probably isn’t the common ancestor of all land animals. Image via Wikimedia Commons/Amelia Guo

On December 23, 1938, South African Hendrick Goosen, the captain of the fishing trawler Nerine, found an unusual fish in his net after a day of fishing in the Indian Ocean off of East London. He showed the creature to  local museum curator Marjorie Courtenay-Latimer, who rinsed off a layer of slime and described it as “the most beautiful fish I had ever seen…five foot long, a pale mauvy blue with faint flecks of whitish spots; it had an iridescent silver-blue-green sheen all over. It was covered in hard scales, and it had four limb-like fins and a strange puppy dog tail.”

The duo, it turned out, had made one of the most significant biological discoveries of the 20th century. The fish was a coelacanth, a creature previously known only from fossilized specimens and believed to have gone extinct about 80 million years earlier. Moreover, its prehistoric appearance and unusual leg-like lobed fins immediately suggested to biologists that it could be an ancient ancestor of all land animals—one of the pivotal sea creatures that first crawled onto solid ground and eventually evolved into amphibians, reptiles, birds and mammals.

Now, though, the coelacanth’s full genome has been sequenced for the first time, and the results, published by an international team of researchers today in Nature, suggest otherwise. Genetic analysis suggests that the coelacanth doesn’t appear to be the most recent shared ancestor between sea and land animals—so its lobed fins didn’t make that first fateful step onto land after all.

When the researchers used what they found out about the coelacanth’s genome to build an evolutionary tree of marine and terrestrial animals (below), they found it’s more likely that ancestors of closely-related class of fish called lungfish played this crucial role. The ancestors of coelacanths and lungfish split off from each other before the latter group first colonized any land areas.

The genetic sequencing showed that terrestrial animals share a more recent common ancestor with lungfish, rather than coelacanths. Image via Nature/Amemiya et. al.

Additionally, the coelacanth’s prehistoric appearance has led to it commonly being considered a “living fossil”: a rare, unchanging biological time capsule of a bygone prehistoric era. But the genomic sequencing indicated that the fish species is actually still evolving—just very, very slowly—supporting the recent argument that it’s time to stop calling the fish and other seemingly prehistoric creatures “living fossils.”

“We found that the genes overall are evolving significantly slower than in every other fish and land vertebrate that we looked at,” Jessica Alföldi, a scientist at MIT and Harvard’s Broad Institute and a co-author, said in a press statement. Small segments of the fish’s DNA had previously been sequenced, but now, she said, “This is the first time that we’ve had a big enough gene set to really see that.”

The fact that the fish is evolving isn’t surprising—like all organisms, it lives in a changing world, with continuously fluctuating selection pressures that drive evolution. What’s surprising (though reflected by its seemingly-prehistoric appearance) is that it’s evolving so slowly, compared to a random sampling of other animals. According to the scientists’ analysis of 251 genes in the fish’s genome, it evolved with an average rate of 0.89 base-pair substitutions for any given site, compared to 1.09 for a chicken and 1.21 for a variety of mammals (base-pair substitution refers to the frequency with with DNA base-pairs—the building blocks of genes—are altered over time).

The research team speculates that the coelacanth’s extremely stable deep Indian Ocean environment and relative lack of predators might explain why it has undergone such slow evolutionary changes. Without new evolutionary pressures that might result from either of these factors, the coelacanth’s genome and outward appearance have only changed slightly in the roughly 400 million years since it first appeared on the planet.

A mixture of plant oils, bacterial spores and ozone is responsible for the powerful scent of fresh rain. Image via Wikimedia Commons/Juni

Step outside after the first storm after a dry spell and it invariably hits you: the sweet, fresh, powerfully evocative smell of fresh rain.

If you’ve ever noticed this mysterious scent and wondered what’s responsible for it, you’re not alone.

Back in 1964, a pair of Australian scientists (Isabel Joy Bear and R. G. Thomas) began the scientific study of rain’s aroma in earnest with an article in Nature titled “Nature of Agrillaceous Odor.” In it, they coined the term petrichor to help explain the phenomenon, combining a pair of Greek roots: petra (stone) and ichor (the blood of gods in ancient myth).

In that study and subsequent research, they determined that one of the main causes of this distinctive smell is a blend of oils secreted by some plants during arid periods. When a rainstorm comes after a drought, compounds from the oils—which accumulate over time in dry rocks and soil—are mixed and released into the air. The duo also observed that the oils inhibit seed germination, and speculated that plants produce them to limit competition for scarce water supplies during dry times.

These airborne oils combine with other compounds to produce the smell. In moist, forested areas in particular, a common substance is geosmin, a chemical produced by a soil-dwelling bacteria known as actinomycetes. The bacteria secrete the compound when they produce spores, then the force of rain landing on the ground sends these spores up into the air, and the moist air conveys the chemical into our noses.

“It’s a very pleasant aroma, sort of a musky smell,” soil specialist Bill Ypsilantis told NPR during an interview on the topic. “You’ll also smell that when you are in your garden and you’re turning over your soil.”

Because these bacteria thrive in wet conditions and produce spores during dry spells, the smell of geosmin is often most pronounced when it rains for the first time in a while, because the largest supply of spores has collected in the soil. Studies have revealed that the human nose is extremely sensitive to geosmin in particular—some people can detect it at concentrations as low as 5 parts per trillion. (Coincidentally, it’s also responsible for the distinctively earthy taste in beets.)

Ozone—O_3, the molecule made up of three oxygen atoms bonded together—also plays a role in the smell, especially after thunderstorms. A lightning bolt’s electrical charge can split oxygen and nitrogen molecules in the atmosphere, and they often recombine into nitric oxide (NO), which then interacts with other chemicals in the atmosphere to produce ozone. Sometimes, you can even smell ozone in the air (it has a sharp scent reminiscent of chlorine) before a storm arrives because it can be carried over long distances from high altitudes.

But apart from the specific chemicals responsible, there’s also the deeper question of why we find the smell of rain pleasant in the first place. Some scientists have speculated that it’s a product of evolution.

Anthropologist Diana Young of the University of Queensland in Australia, for example, who studied the culture of Western Australia’s Pitjantjatjara people, has observed that they associate the smell of rain with the color green, hinting at the deep-seated link between a season’s first rain and the expectation of growth and associated game animals, both crucial for their diet. She calls this “cultural synesthesia”—the blending of different sensory experiences on a society-wide scale due to evolutionary history.

It’s not a major leap to imagine how other cultures might similarly have positive associations of rain embedded in their collective consciousness—humans around the world, after all, require either plants or animals to eat, and both are more plentiful in rainy times than during drought. If this hypothesis is correct, then the next time you relish the scent of fresh rain, think of it as a cultural imprint, derived from your ancestors.

The new robot runs across an uneven surface in a way modeled off a zebra-tailed lizard. Image courtesy of Chen Li, Tingnan Zhang, Daniel Goldman

Designing a robot that can easily move across loose terrain—say, a rover meant to traverse the surface of Mars—poses a unique engineering challenge: Wheels commonly sink into what engineers call “flowable ground” (mixtures of sand, soil, mud and grass).

Given the many biologically-inspired innovations in robotics, a team of researchers from Georgia Tech had an idea—to base a design on desert creatures such as zebra-tailed lizards that are able to scramble across a loose, sandy surface without slowing down. Their efforts allowed them to create this small six-legged device, presented in an article published today in Science, which can run across a granular surface in a way uncannily reminiscent of a reptile.

The research team, led by Chen Li, designed the device after studying the locomotion of various creatures and mathematically simulating the performance of different types of legs (varying in number, shape and length) in several distinct environments. They hope their research will spur the development of a field they’ve termed “terradynamics”—just as aerodynamics is concerned with the performance of winged vehicles in air, their field will study the motion of legged vehicles on granular surfaces.

To design their robot, they used these simulations to determine the exact leg lengths, movement speeds and levels of force that would propel devices across a loose surface without causing them to sink in too deeply. They then printed a variety of leg types with a 3D printer, and built robots to test them in the lab.

One of their most interesting findings is that the same types of design principles apply for locomotion on a variety of granular surfaces, including poppy seeds, glass beads and natural sand. Their simulations and real-world experiments revealed that C-shaped legs generally worked best, but that any type of bow-shaped limbs worked relatively well because they spread out the weight of the device over long (albeit narrow) leg surfaces as the legs come into contact with the ground over the course of a stride.

The researchers found that C-shaped limbs work best for moving quickly over granular surfaces, both in lizards and robots. Dashed, solid, and dotted depictions in C and D are early, middle, and late leg positions during a stride. Arrows indicate directions of motion for specific leg regions. Image via Science/Li et. al.

The applications of this kind research are broad: This particular robot, the researchers say, could be developed into a useful search-and-rescue or scouting device, while the principles derived from the field of terradynamics could be useful in designing probes to explore other planets in the future. They could also help biologists to better understand the how life forms here on earth have evolved to move across our planet’s surface.

The hole in the top of this 100,000-year-old skull from China, researchers say, reflects genetic mutations that result from inbreeding. Image via PLOS ONE/Wu et. al.

In 2010, the surprising discovery that Neanderthals likely crossbred with our ancestors tens of thousands of years ago generated headlines around the world.

Now, we have a new finding about the sex lives of early Homo sapiens: It looks like they engaged in some inbreeding as well.

That is the conclusion of anthropologist Erik Trinkhaus of Washington University in St. Louis and Xiu-Jie Wu and Song Xing of the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology, based on a fractured 100,000-year-old skull excavated from China’s Nihewan Basin. Their finding, published yesterday in PLOS ONE, is that the skull shows evidence of an unusual genetic mutation that is likely the result of high levels of inbreeding.

The researchers used CT scanning and 3D modeling to join together for the first time the 5 pieces of the fractured skull—known as Xujiayao 11, named for the site where it was found back in 1977—and realized that it exhibited an unusual deformity. When the pieces are combined, they leave a hole on the crown of the skull, but there is no evidence that the fracture was caused by a traumatic injury or disease. As a result, they consider it most likely that the hole is a defect known as an enlarged parietal foramen.

The researchers use CT scans and 3D modeling to piece together the fractured skull for the first time. Image via PLOS ONE/Wu et. al.

Nowadays, this hole is mostly found in people with a particular pair of genetic mutations on chromosomes 5 and 11—most often a consequence of inbreeding—and occurs in about 1 of 25,000 live births. The mutation interferes with bone formation in the skull over the first five months of an infant’s life, when the pieces of the skull are supposed to fuse together to cover up the “soft spot.”

Given the tiny sample size of human skulls this old and the fact that similar kinds of genetic abnormalities have been seen so often in other prehistoric skulls—the researchers count 22 individuals with skull deformities discovered from this era—Trinkhaus thinks the simplest explanation is that small and unstable human populations forced our ancestors to inbreed.

If no inbreeding occurred, “the probability of finding one of these abnormalities in the small available sample of human fossils is very low, and the cumulative probability of finding so many is exceedingly small,” he said in a press statement. “The presence of the Xujiayao and other Pleistocene [2.6 million to 12,000 years ago] human abnormalities therefore suggests unusual population dynamics, most likely from high levels of inbreeding and local population instability.”

Such inbreeding was likely inevitable, given that most of humanity likely lived in small, isolated populations for most of our species’ evolution. For example, some scientists believe that an earlier population bottleneck that predated this skull may have driven the worldwide human population to as low as 2,000 individuals, at times making inbreeding a necessity. Our ancestors certainly didn’t understand the importance of genetic diversity and the dangerous consequences of inbreeding. But with such a scant population, the survival of our species might actually have depended on our ancient grandmothers procreating with their male relatives.

The good news? The researchers say that the genetic deformity preserved in this skull as a result of inbreeding may not have been too detrimental for this individual. Normally, it’s linked with major cognitive problems, but that’s doubtful in this case, given the demanding conditions of surviving in the Pleistocene. This prehistoric human appears to have survived to a ripe old age—which, in those days, probably means the individual lived into his or her thirties.

A fossil of a prehistoric bird from the enantiornithine genus shows feathers on its hind legs—evidence of an extra pair of wings. Courtesy of Xiaoting Zheng et al/Science

Roughly 150 million years ago, birds began to evolve. The winged creatures we see in the skies today descended from a group of dinosaurs called theropods, which included tyrannosaurs, during a 54-million-year chunk of time known as the Jurassic period. Why the ability to fly evolved in some species is a difficult question to answer, but scientists agree that wings came to be because they must have been useful: they might have helped land-based animals leap into the air, or helped gliding creatures who flapped their arms produce thrust.

As researchers continue to probe the origin of flight, studies of fossils have shown that theropods–particularly coelurosaurian dinosaurs, which closely resemble modern birds—had large feathers on both their fore limbs and hind limbs. However, extensive evidence for these leg feathers didn’t exist in the earliest birds. But now, a new examination of fossils reported today in the journal Science reveals several examples of this four-winged anatomy in modern birds’ oldest common ancestors.

Modern birds have two types of feathers: vaned feathers that cover the outside of the body, and the down feathers that grow underneath them. Researchers studying the approximately 120 million-year-old fossils of 11 primitive birds from the Shandong Tianyu Museum of Natural History in China found that one type of vaned plumage, also known as pennaceous feathers, was neatly preserved in skeletal fossils of these specimens, along each creatures’ hind limbs. After this find, the researchers must have been flying high: The feathers of birds’ wings, known as flight feathers, are long, stiff and asymmetrically shaped pennaceous feathers, similar to those found in the fossils. When fanned together, pennaceous feathers form the broad surfaces of birds’ wingspans—without these surfaces, birds cannot stay aloft.

Pennaceous feathers, which are composed of many flattened barbs, existed in some winged dinosaurs. Finding them on the hind legs of early birds suggests that before birds used two wings to fly, they may have depended on four. Over millions of years, however, birds gradually lost the feathers on this extra set of wings.

The study adds to existing theories that suggest the first birds flew with four wings. Examination of a primitive bird fossil from the Archaeopteryx genus in 2004 revealed long feathers on the animal’s back and legs, which would have aided its gliding ability. Two years later, another study of the crow-sized animal, which lived about 150 million years ago, reported that the prehistoric bird’s feathers resembled those on modern birds’ flight wings.

One of the more complete skeletons examined in today’s study actually showed hind-limb pennaceous feathers along the bone of each leg. The longest feather stretched almost two inches, which is remarkable considering that the legs they covered were between one inch and two and a half inches long. In fact, specimens from a group of birds called Enantiornithes, which externally resemble modern birds, showed symmetrically paired large feathers preserved along their hind leg bones. Such feather arrangement is present in modern birds’ wings.

Researchers speculate that the second set of wings might have provided extra lift or created drag in the air. They might also have helped birds maneuver their airborne bodies.

If these hind wings indeed served a functional purpose in fight, they will earn an important place in bird evolution. Bird movement is characterized by a combination of feathered arms for flight and legs for walking on land. This study suggests that if walking legs, present in birds today, developed after these feathered hind legs, then the loss of feathers on the back legs—and thus an extra pair of wings—reflects a period of change during which the arms became specialized for flight and the legs, for locomotion.

Today, leg feathers are less well developed than wing feathers—they are usually much smaller and fluffy—and they serve as protection and insulation for the leg. These fluffy bits are sparse too—instead, the legs are covered in scales, which form only if feather growth is inhibited. Studies of modern birds show how this works. As chicks develop from embryos and grow into adults, feathered legs can be transformed into scaled legs, or vice versa, by altering how certain genes are expressed.

The recent revelation about feathers on birds’ hind legs suggest that a similar genetic, and more permanent, change might have occurred early in bird evolution, according to lead researchers. This shift triggered the loss of birds’ hind wings, pushing the creatures down an evolutionary path that would allow them to fly with just two.

A Neanderthal’s skull (right) was larger than a human’s (left) and had a similar inner volume for mental capacity, but new research indicates less of it was devoted to higher-order thinking. Image via Wikimedia Commons/DrMikeBaxter

Neanderthals never invented written language, developed agriculture or progressed past the Stone Age. At the same time, they had brains just as big in volume as modern humans’. The question of why we Homo sapiens are significantly more intelligent than the similarly big-brained Neanderthals—and why we survived and proliferated while they went extinct—has puzzled scientists for some time.

Now, a new study by Oxford researchers provides evidence for a novel explanation. As they detail in a paper published today in the Proceedings of the Royal Society B, a greater percentage of the Neanderthal brain seems to have been devoted to vision and control of their larger bodies, leaving less mental real estate for higher thinking and social interactions.

The research team, led by Eiluned Pearce, came to the finding by comparing the skulls of 13 Neanderthals who lived 27,000 to 75,000 years ago to 32 human skulls from the same era. In contrast to previous studies, which merely measured the interior of Neanderthal skulls to arrive at a brain volume, the researchers attempted to come to a “corrected” volume, which would account for the fact that the Neanderthals’ brains were in control of rather differently-proportioned bodies than ours ancestors’ brains were.

A replica of the La Ferrassie 1 Neanderthal skull, the largest and most complete Neanderthal skull ever found. Image via the Natural History Museum London

One of the easiest differences to quantify, they found, was the size of the visual cortex—the part of the brain responsible for interpreting visual information. In primates, the volume of this area is roughly proportional to the size of the animal’s eyes, so by measuring the Neanderthals’ eye sockets, they could get a decent approximation of their the visual cortex as well. The Neanderthals, it turns out, had much larger eyes than ancient humans. The researchers speculate that this could be because they evolved exclusively in Europe, which is of higher latitude (and thus has poorer light conditions) than Africa, where H. sapiens evolved.

Along with eyes, Neanderthals had significantly larger bodies than humans, with wider shoulders, thicker bones and a more robust build overall. To account for this difference, the researchers drew upon previous research into the estimated body masses of the skeletons found with these skulls and of other Neanderthals. In primates, the amount of brain capacity devoted to body control is also proportionate to body size, so the scientists were able to calculate roughly how much of the Neanderthals’ brains were assigned to this task.

After correcting for these differences, the research team found that the amount of brain volume left over for other tasks—in other words, the mental capacity not devoted to seeing the world or moving the body—was significantly smaller for Neanderthals than for ancient H. sapiens. Although the average raw brain volumes of the two groups studied were practically identical (1473.84 cubic centimeters for humans versus 1473.46 for Neanderthals), the average “corrected” Neanderthal brain volume was just 1133.98 cubic centimeters, compared to 1332.41 for the humans.

This divergence in mental capacity for higher cognition and social networking, the researcher argue, could have led to the wildly different fates of H. sapiens and Neanderthals. “Having less brain available to manage the social world has profound implications for the Neanderthals’ ability to maintain extended trading networks,” Robin Dunbar, one of the co-authors, said in a press statement. “[They] are likely also to have resulted in less well developed material culture—which, between them, may have left them more exposed than modern humans when facing the ecological challenges of the Ice Ages.”

Previous studies have also suggested that the internal organization of Neanderthal brains differed significantly from ours. For example, a 2010 project used computerized 3D modeling and Neanderthal skulls of varying ages to find that their brains developed at different rates over the course of an individual’s adolescence as compared to human brains despite comparable brain volumes.

The overall explanation for why Neanderthals went extinct while we survived, of course, is more complicated. Emerging evidence points to the idea that Neaderthals were smarter than previously thought, though perhaps not smart enough to outmaneuver humans for resources. But not all of them had to—in another major 2010 discovery,a team of researchers compared human and Neanderthal genomes and found evidence that our ancestors in Eurasia may have interbred with Neanderthals, preserving a few of their genes amidst our present-day DNA.

Apart from the offspring of a small number of rare interbreeding events, though, the Neanderthals did die out. Their brains might have been just as big as ours, but ours might have been better at a few key tasks–those involved in building social bonds in particular—allowing us to survive the most recent glacial period while the Neanderthals expired.

A new DNA analysis confirms that this ancient skull, found in a Siberian cave, was an early ancestor of man’s best friend. Image via PLOS ONE/Ovodov et. al.

In 1975, a team of Russian archaeologists announced that they’d made a remarkable find: From a cave in the Altai Mountains of Siberia, they’d unearthed a 33,000-year-old fossil skull that resembled a wolf. In 2011, an anatomical analysis suggested that the fossil was a hybrid of a wolf (with its large teeth) and a dog (with its shortened snout), raising the possibility that it was a partly domesticated wolf—in other words, one of the oldest ancestors of the modern dog ever discovered.

At the time, though, DNA analysis was needed to make certain that the fossil came from an ancestor of man’s best friend. A paper published today in the journal PLOS ONE confirms that fact, indicating that the creature was more closely related to modern dogs than wolves, and forcing scientists to reconsider the dog’s evolutionary family tree.

A top view of the skull. Image via PLOS ONE/Ovodov et. al.

A bottom view of the skull. Image via PLOS ONE/Ovodov et. al.

To come to the finding, a team led by Anna Druzhkova of the Russian Academy of Sciences sequenced mitochondrial DNA taken from one of the skull’s teeth. This type of genetic material comes from an organelle inside each cell called the mitochondria, which has a distinct type of DNA that’s separate from the cell’s normal chromosomes. For each individual, mitochondrial DNA is inherited directly from one’s mother without any modifications and thus remains relatively constant over generations, except for the gradual effect of mutations. Similarities found in such DNA collected from various animals helps scientists understand the evolutionary relationships between species.

The research team compared their sample of mitochondrial DNA from the ancient skull with samples from 70 different modern breeds of dog, along with 30 different wolf and 4 different coyote DNA samples. Their analysis found that the fossil’s DNA didn’t match any of the other samples perfectly, but most closely resembled the modern dog breeds, sharing the most similarities with Tibetian Mastiffs, Newfoundlands and Siberian Huskies in particular.

Scientists know that dogs evolved as a result of the domestication of wolves, but the specific time and location of this domestication is still poorly understood—and this discovery further complicates that picture. Most experts agree that dogs predate the invention of agriculture (which happened roughly 10,000 years ago), but some say that domestication may have occurred as long as 100,000 years ago.

This finding—and the previous radiocarbon dating of the skull which established its age—set that event to at least 33,000 years ago. However, dogs may have been domesticated from wolves multiple times, and this breed of Siberian dog may have actually gone extinct, rather than serving as an ancestor for modern dogs. Archaeological evidence indicates that, with the onset of the last glacial maximum (around 26,000 years ago), humans in this area of Siberia may have stopped domesticating dogs, maybe due to food scarcity. In that case, an independent domestication elsewhere may have led to the dogs of today.

On the other hand, domestication in the vicinity of the Altai Mountains, as evidenced by this finding, may have led to the geographic spread of dogs elsewhere in Asia and Europe, even if they died out in Siberia. Previously, many have suggested that the first domestication occurred in the Middle East or East Asia, but this skull could force scientists to rethink their theories. The research team behind the analysis notes that finding more ancient dog remains will help us in putting together the puzzle.

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Scientists discovered that the penguins plumage is even colder than the surrounding air, potentially allowing them to absorb heat through convection. Image © Université de Strasbourg and Centre National de la Recherche Scientifique (CNRS), Strasbourg, France

Antarctica, as you might expect, gets pretty darn cold: Temperatures as low as -40 degrees Fahrenheit are often recorded during the winter. For the creatures who live there, this extreme cold demands innovative survival strategies that enable the loss of as little heat as possible.

Scientists recently discovered that Emperor Penguins—one of Antarctica’s most celebrated species—employ a particularly unusual technique for surviving the daily chill. As detailed in an article published today in the journal Biology Letters, the birds minimize heat loss by keeping the outer surface of their plumage below the temperature of the surrounding air.

At the same time, the penguins’ thick plumage insulates their body and keeps it toasty. A team of scientists from Scotland and France recently came to the finding by analyzing thermal images (below) of penguins taken at a coastal Emperor breeding colony in Adélie Land, an area of Antarctica claimed by France.

The research drew upon theromgraphic images of the penguins collected in the wild. Image © Université de Strasbourg and Centre National de la Recherche Scientifique (CNRS), Strasbourg, France

The researchers analyzed thermographic images like this one taken over roughly a month during June 2008. During that period, the average air temperature was 0.32 degrees Fahreinheit. At the same time, the majority of the plumage covering the penguins’ bodies was even colder: the surface of their warmest body part, their feet, was an average 1.76 degrees Fahrenheit, but the plumage on their heads, chests and backs were -1.84, -7.24 and -9.76 degrees Fahrenheit respectively. Overall, nearly the entire outer surface of the penguins’ bodies was below freezing at all times, except for their eyes and beaks.

The scientists also used a computer simulation to determine how much heat was lost or gained from each part of the body—and discovered that by keeping their outer surface below air temperature, the birds might paradoxically be able to draw very slight amounts of heat from the air around them. The key to their trick is the difference between two different types of heat transfer: radiation and convection.

The penguins do lose internal body heat to the surrounding air through thermal radiation, just as our bodies do on a cold day. Because their bodies (but not surface plumage) are warmer than the surrounding air, heat gradually radiates outward over time, moving from a warmer material to a colder one. To maintain body temperature while losing heat, penguins, like all warm-blooded animals, rely on the metabolism of food.

The penguins, though, have an additional strategy. Since their outer plumage is even colder than the air, the simulation showed that they might gain back a little of this heat through thermal convection—the transfer of heat via the movement of a fluid (in this case, the air). As the cold Antarctic air cycles around their bodies, slightly warmer air comes into contact with the plumage and donates minute amounts of heat back to the penguins, then cycles away at a slightly colder temperature.

Most of this heat, the researchers note, probably doesn’t make it all the way through the plumage and back to the penguins’ bodies, but it could make a slight difference. At the very least, the method by which a penguin’s plumage wicks heat from the bitterly cold air that surrounds it helps to cancel out some of the heat that’s radiating from its interior.

And given the Emperors’ unusually demanding breeding cycle (celebrated in the documentary March of the Penguins), every bit of warmth counts. Each winter, they trek from inland coastal locations to the coast inland—walking as far as 75 miles—where they breed and incubate their eggs. After the females lay eggs, the males incubate them by balancing them on top of their feet in a pouch for roughly 64 days. Since they don’t eat anything during this entire period, conserving calories by giving up as little heat as possible is absolutely crucial.

Photo by Philippe Verbelen

Indonesia’s numerous islands (18,307 to be exact) house a wealth of avian biodiversity, yet scientists speculate that many of the country’s bird species have yet to be discovered or categorized. But ornithologists are celebrating today as a new species of owl joins the list, taking filling in one more spot in the catalog of the archipelago’s animals.

In 2003, George Sangster, a Dutch ornithologist from Stockholm University, and his wife were exploring the forested foothills of Lombak, an island just east of Bali. While traipsing through the forest at night, Sangster picked up on an owl call he did not recognize. Coincidentally, just a few days later Ben King, an ornithologist from the American Museum of Natural History, heard those same calls from the jungle and also suspected they came from an unknown species.

“It was quite a coincidence that two of us identified this new bird species on different parts of the same island, within a few days of being on the island, especially considering that no-one had noticed anything special about these owls in the previous 100 years,” Sangster said in a statement.

Locals on Lombak, it turned out, were familiar with the species. Known as burung pok–roughly translated as “pook,” a mimic of the owl’s hoots–the birds turned out to be a common feature of the nocturnal landscape. But locals on neighboring islands, however, said they had never heard of the bird and did not recognize its unusual call.

Here, you can hear the little Indonesian owl hooting into the night, which the researchers describe as “a single whistle without overtones:

Although birders and scientists alike love owls, surprisingly not much is known about those species’ biology, including how they relate to one another on an evolutionary scale. Lately, however, researchers have been working double time to get a grip on owls. In 1975, for example, scientists knew of 146 species, and that number leapt to 250 as of 2008. One driver behind this jump in species numbers was the realization that owl calls could lend clues (PDF) to classifying different types of owls. Owls hoot to attract mates and recognize one another as the same, so animals evolved calls unique to their species. In some cases, owls previously classified as the same species were split in two primarily on the basis of their calls.

Sangster, King and two other researchers from Sweden and Australia got together and were able to photograph the owls by playing back recordings of the call to attract several of the hooting culprits. Digging through old records, the researchers found that the owls matched specimens collected back in 1896 by Alfred Everett, a British administrator who was based in Borneo and spent his spare time collecting natural history curios. That same year, Ernest Hartlet, a naturalist who reported on Everett’s field work, accurately noted that “the cry is a clear but not very loud ‘pwok,’ like that of [O.] lempiji, but somewhat different in tone.”

Though Hartlet and Everett came close to identifying the new species, they fell just short of making the leap. Since then, no one had collected or observed this type of owl, according to records from the American Museum of Natural History and the Natural History Museum at Tring, in the U.K. 

All of this evidence, the team concluded in a PLoS ONE paper, pointed to the discovery of a new species of owl.

Because the new owl shows dramatically less individual variation to its brown and cream-speckled feather patterns than similar species found on neighboring islands, the scientists hypothesize that ancestors of the Lombok owls may have been isolated and trapped on their island many years before by a catastrophic volcanic eruption. Starting with just a handful of individuals, the animals then could have slowly rebuilt their populations, eventually evolving into a unique lineage.

The species, they report, is the first bird known to be unique to Lombok. The authors named the new bird Otus jolandae, after Sangster’s wife, Jolanda.

The utterly strange-looking star-nosed mole sees the world with one of the most sensitive touch organs in the animal kingdom. Photo by Kenneth Catania

That’s an actual, earthly animal you’re looking at in the photo above—not, as you might have assumed, a creature out of Star Wars. The star-nosed mole, which resides in the bogs and wetlands of the eastern U.S. and Canada, is roughly the size of a rat when fully-grown. It’s functionally blind and eats insects, worms and small fish.

But the most noticeable aspect of the animal is its utterly strange appearance, dominated by its 22-tentacled ultra-sensitive snout, called a star (those aren’t its eyes and face at the center of the pink fleshy area, but rather its nostrils). This snout, used to hunt and grab prey, features more than 100,000 nerve endings packed into an area barely more than 1 cm in diameter, making it one of the most sensitive touch organs in the whole animal kingdom.

A star-nosed mole searches for prey with its star. Photo by Kristin Gerhold and Diana Bautista

In a paper published today in the journal PLOS ONE, a team of biologists and neuroscientists from UC Berkeley and Vanderbilt University have examined the activity of the mole’s star on a molecular level to figure out just how it conveys information to the animal’s brain. One of the team’s most interesting findings is that the star is relatively poor in neurons sensitive to pain, but extremely rich in neurons specifically adapted to be touch-sensitive.

Each of the star’s 22 tentacles (called “rays”) is covered by small domed structures known as Eimer’s organs—the average snout has some 30,000 in total. By way of contrast, an entire human hand contains roughly 17,000 touch fibers (which are analogous to Eimer’s organs), but the mole’s star is smaller than a single human fingertip.

One of the study’s authors, Vanderbilt neuroscientist Kenneth Catania, has studied the strange animal for more than two decades and has previously suggested that, for the mole, the sensory information it receives from its star most closely resembles the visual information we get from our eyes. That is, just as our world is largely defined by visual stimuli, the star-nosed mole’s is most directly defined by touch.

For evidence, he points to the fact that the moles’ brains are spatially organized around tactile signals coming from their stars in much the same way our brains are arranged the visual information generated by their eyes. Their neocortex—the outer layers of each of the brain’s hemispheres—features a map of nerves that spatially corresponds with the data coming from each of the star’s rays. That is, the brain region that matches up with one particular ray is adjacent to the region that matches with the next ray over. Our visual cortex is arranged in much the same manner.

The moles’ use of their stars also resembles the way we (and many other mammals) use our eyes to understand our environment. When Catania and other researchers filmed the moles’ behavior, they discovered that upon coming into contact with an object of interest, the moles immediately began rapidly probing it with their smallest rays (the two hanging at the bottom-center of the star).

This is similar to the way primates use vision, relying on short, rapid eye movements so that the fovea centralis—the central, highest-resolution part of the eye—to can discern visual details. What’s most fascinating is that both the moles’ smallest rays and our fovea centralis are over-represented in terms of area in the neocortex. Thus, instead of seeing the world with eyes, the functionally blind star-nosed mole apparently ‘sees’ its underground environment with its snout.

Image via SuperFantastic

It’s conventional wisdom that three things in life are inevitable: death, taxes and smelly armpits. But the third trouble on that list, it turns out, only afflicts 98% of us. According to a group of researchers from the University of Bristol in the UK, 2 percent of people (at least in their survey) carry a rare version of the gene ABCC11 that prevents their armpits from producing an offensive odor.

The study, published yesterday in the Journal of Investigative Dermatology, examined 6,495 British mothers who have been part of a longitudinal health study since they gave birth in either 1991 or 1992. About 2 percent—117 mothers, to be exact—had the gene, according to DNA analysis.

Researchers have apparently known that this gene exists for some time, although most work on it has focused on its connection to earwax: People with the rare gene variant are more likely to have “dry” earwax (as opposed to wet or sticky). Thus, one way to try figuring out if you’ve been blessed with stink-free armpits is to consider whether your earwax is uncommonly dry. It’s also been discovered that the non-stinky gene is more common in East Asian populations.

Researchers still aren’t sure how the gene affects both earwax and sweat odor, but they believe it has to do with amino acid production. Rapidly growing bacteria give sweat its smelliness, and people with the rare gene variant appear to produce less of an animo acid that engenders bacteria growth.

This particular study examined just how many of these remarkable individuals still wear deodorant despite their lucky genetic inheritance. Whether they knew that they carried the gene or not, people with the trait were less likely to wear deodorant or antiperspirant: 78% reported wearing it on all or most days, versus 95% of the others in the study. At some point in their lives, a decent proportion must have figured out that they really don’t need to wear these sorts of products to avoid stinking.

Still, most of the people with the gene wake up everyday and apply deodorant, a trend the researchers chalk up to socio-cultural norms. They think their findings could save these people a little money and trouble and let them skip deodorant entirely.

“These findings have some potential for using genetics in the choice of personal hygiene products,” Santio Rodriguez, the lead author, said in a statement. “A simple gene test might strengthen self-awareness and save some unnecessary purchases and chemical exposures for non-odour producers.”

A noble cause, indeed. We have just one suggestion: You may want to confirm you have the gene before leaving the house au naturale.

A new study shows that when our fingers get wrinkly, they’re better at gripping wet objects. Image via Wikimedia Commons/Fir0002/Flagstaffotos

Standing in the shower or sitting in the tub, many of us have looked at our wrinkled fingertips and had occasion to wonder: Why do they get so pruney when wet?

Over the years, people have pointed to a number of explanations, most commonly the idea that the wrinkles are simply a reflection of the skin absorbing water. Now, according to a study published yesterday in the journal Biology Letters by researchers from Newcastle University in the UK, we have a definitive (and more interesting) explanation: Pruney fingers are better at gripping wet objects.

The idea was first suggested in a 2011 paper, which showed that the wrinkles that form on our fingers exhibit consistent patterns that allow water to sluice away—indicating that their role is to improve traction, like the tread on a tire. For this paper, an unrelated group of researchers put the theory to the test, letting twenty volunteers soak their fingers in warm water for 30 minutes to get them good and pruney, then testing exactly how long it took them to move wet glass marbles and fishing weights from one container to another.

On average, pruney-fingered participants moved wet marbles 12 percent more quickly than when they were tested unwrinkled fingers. When the same test was performed with dry marbles, the times were roughly the same. Thus, it seems, the hypothesis was proved: pruney fingers do help us grip better.

Other research has shown that the wrinkles form as a result of blood vessels beneath the skin constricting, as directed by the autonomic nervous system. Because this is an active process—rather than merely a byproduct of the skin absorbing water, as previously assumed—scientists began looking for the underlying reason why this might be the case.

The gripping hypothesis makes sense from an evolutionary standpoint, too. “Going back in time, this wrinkling of our fingers in wet conditions could have helped with gathering food from wet vegetation or streams,” study coauthor and behavioral researcher Tom Smulders said in a press statement. “And as we see the effect in our toes too, this may have been an advantage as it may have meant our ancestors were able to get a better footing in the rain.”

If pruney fingers are better at gripping wet objects and don’t slow us down with dry ones, though, the theory prompts a question: Why aren’t our fingers permanently wrinkled? The study’s authors acknowledge this query and admit they don’t have a ready answer, but speculate that permanent pruniness could limit our fingers’ sensitivity or even make them more likely to be cut by sharp objects.

Baby bonobos share papayas. Photo from Jingzhi Tan

In 1719, Daniel Defoe wrote in Robinson Crusoe, ”He declar’d he had reserv’d nothing from the Men, and went Share and Share alike with them in every Bit they eat.” Defoe’s famous sharing phrase has persisted throughout the years, passing from parent to child as a lesson on the virtues of sharing with family, peers and even strangers.

But in the context of evolution and survival of the fittest, sharing makes no sense. Until now, scientists assumed that humans alone subscribed to this behavior, especially when it comes to sharing with strangers, and wrote the trait off as a quirk stemming from our unique cognitive and social development.

Sure, primatologists know that great apes help and voluntarily share food with other group mates (acts that indirectly benefits themselves). But strangers? Such a behavior is unheard of amidst species that often compete aggressively with other groups and even murder foreign individuals.

Researchers from Duke University decided to challenge the great ape’s bad sharing rep, seeking to discover whether or not our furry relatives may also have a propensity for partitioning goods with animals they do not know. The scientists chose bonobos–a type of great ape sometimes referred to as a pygmy chimpanzee–for their study. Compared to chimpanzees, bonobos possess a relatively high tolerance for strangers, so they seemed like a logical candidate for investigations into the nature of sharing.

At a bonobo sanctuary in the Democratic Republic of the Congo, they enrolled 15 wild-born bonobos orphaned and rescued from the illegal wildlife trade in four experiments. In the first experiment, the researchers led a bonobo into a room piled high with delicious banana slices. Behind two sliding doors, they placed either a friend of the main bonobo or a stranger (a bonobo unrelated and unknown to their main research subject). The bonobo with the bananas could chose to eat the food all on its own, or open the sliding door and invite both or either the friend or stranger to join in. In the second experiment, they placed only one bonobo–either the friend or stranger–behind a door and left the second room empty.

The results, which they describe this week in the journal PLoS One, confounded the researchers. In more than 70 percent of the trials, the bonobos shared their food at least once. They preferred to release the stranger over their group mate, and the stranger in turn often released the other bonobo, even though that meant splitting the food three ways and being outnumbered by two bonobos that already knew each other. They ignored the door leading to the empty room, showing that the novelty of opening the door was not motivating their behavior.

So, were the bonobos willing to share their food with strangers because of an overwhelming desire to interact with the unknown apes, or were they motivated by a sense of altruism? The researchers set up two more experiments to find out. They arranged a rope which, when pulled, released either a bonobo stranger or friend into a room which held more bananas. A mesh divider separated the main bonobo from that room, however, meaning it could neither reach the food or interact directly with the released ape. Even when there was no immediate social or culinary reward on offer, the researchers found, 9 out of 10 bonobos still chose to release their friend or the stranger at least once, allowing the other ape to reach the banana reward.

Bonobos drew the line, however, in the final experiment. This setup allowed both bonobos to access the food, but did not let them interact physically with the stranger or friend. In other words, the main bonobo would have to forfeit some of its food but receive no reward of sniffing, petting or playing with another ape. None of the bonobos chose to open the door, suggesting that the seemingly altruistic sharing of the first two experiments was just a ploy to gain gratifying access to intriguing strangers and, to a lesser extent, friends. The third experiment, however, shows that the bonobos’ motivations are not completely selfish. When the food was so far out of reach that they themselves could not benefit, they allowed a friend or stranger to enjoy it instead.

Bonobos, in other words, break the rules when it comes to sharing, showing that kindness towards strangers is not unique to humans. Oddly enough, unlike their bipedal counterparts, bonobos even seem to prefer strangers to group mates. This behavior, the study authors think, might have evolved to help groups of bonobos expand their social networks. Further investigations may lend clues about evolution of sharing in humans.

“Like chimpanzees, our species would kill strangers; like bonobos, we could also be very nice to strangers,” said Jingzhi Tan, an evolutionary anthropologist at Duke University and lead author of the paper, in a statement. “Our results highlight the importance of studying bonobos to fully understand the origins of such human behaviors.”

A new study shows that microscopic barbs allow porcupine quills to slice into flesh easily and stay there stubbornly. Image via Jeffrey Karp

If you’ve ever had a violent encounter with a porcupine, it probably didn’t end well. The large rodents are most well-known for the coat of some 30,000 barbed quills that cover their backs, an evolutionary adaptation to protect against predators. Although they appear thin—even flimsy—once quills lodge in your flesh, they’re remarkably difficult and painful to get out.

Recently, a group of scientists led by Jeffrey Karp of Harvard decided to closely investigate just what makes these quills so effective. As they report in an article published today in the Proceedings of the National Academy of Sciences, their analysis revealed a specialized microscopic barbed structure that enables the quills to slide into tissue extremely easily but cling to it stubbornly once it’s in place.

A microscopic image of a porcupine quill’s barbs. Image via Jeffrey Karp

Each cylindrical quill, it turns out, is coated with backwards-facing barbs interspersed with smooth, scale-like structures. When a porcupine brushes up against an adversary (or against anything else), it sheds its quills; the barbs around the circumference of the quill act like the teeth on a slicing serrated knife, providing a cleaner cut into tissue and making penetration easier. Once the quill has dug into the other animal, these same barbs have the opposite effect, lifting up and preventing the needle from sliding out easily.

The researchers took a rather interesting approach to arrive at these findings: They measured how much force it took to push in and pull out porcupine quills into pig skin and raw chicken meat. They then performed the same experiment with other quills, which they’d rendered smooth by carefully sanding off all the barbs.

All this research had a greater purpose than merely satisfying the authors’ curiosity about porcupines. Like velcro (inspired by plants’ burrs that get stuck on your clothing) and tape-based adhesives (inspired by the sticky coating on geckos’ hands and feet), the scientists studied the characteristics that made the barbs so effective in hopes of developing next-generation hypodermic needles.

If one could be designed that would require less force to penetrate human tissue, it might mean less pain with your next flu shot. The quills’ staying power could be useful for needles that need to stay in place for a longer period of time, like an I.V. drip.

As a proof-of-principle, the team made replica porcupine quills made out of plastic and put them through the same battery of tests on tissue and skin. The plastic quills worked like a charm. The researchers speculate that such technology could someday be incorporated into a range of medical applications beyond hypodermic needles, such as staples that hold wounds together during healing and adhesives used to hold drug delivery systems in place.