Showing posts with label Health. Show all posts
Showing posts with label Health. Show all posts

We Didn’t Domesticate Dogs. They Domesticated Us.


In the story of how the dog came in from the cold and onto our sofas, we tend to give ourselves a little too much credit. The most common assumption is that some hunter-gatherer with a soft spot for cuteness found some wolf puppies and adopted them. Over time, these tamed wolves would have shown their prowess at hunting, so humans kept them around the campfire until they evolved into dogs. (See "How to Build a Dog.")

But when we look back at our relationship with wolves throughout history, this doesn't really make sense. For one thing, the wolf was domesticated at a time when modern humans were not very tolerant of carnivorous competitors. In fact, after modern humans arrived in Europe around 43,000 years ago, they pretty much wiped out every large carnivore that existed, including saber-toothed cats and giant hyenas. The fossil record doesn't reveal whether these large carnivores starved to death because modern humans took most of the meat or whether humans picked them off on purpose. Either way, most of the Ice Age bestiary went extinct.

The hunting hypothesis, that humans used wolves to hunt, doesn't hold up either. Humans were already successful hunters without wolves, more successful than every other large carnivore. Wolves eat a lot of meat, as much as one deer per ten wolves every day-a lot for humans to feed or compete against. And anyone who has seen wolves in a feeding frenzy knows that wolves don't like to share.

Humans have a long history of eradicating wolves, rather than trying to adopt them. Over the last few centuries, almost every culture has hunted wolves to extinction. The first written record of the wolf's persecution was in the sixth century B.C. when Solon of Athens offered a bounty for every wolf killed. The last wolf was killed in England in the 16th century under the order of Henry VII. In Scotland, the forested landscape made wolves more difficult to kill. In response, the Scots burned the forests. North American wolves were not much better off. By 1930, there was not a wolf left in the 48 contiguous states of America.  (See "Wolf Wars.")

If this is a snapshot of our behavior toward wolves over the centuries, it presents one of the most perplexing problems: How was this misunderstood creature tolerated by humans long enough to evolve into the domestic dog?

The short version is that we often think of evolution as being the survival of the fittest, where the strong and the dominant survive and the soft and weak perish. But essentially, far from the survival of the leanest and meanest, the success of dogs comes down to survival of the friendliest.

Most likely, it was wolves that approached us, not the other way around, probably while they were scavenging around garbage dumps on the edge of human settlements. The wolves that were bold but aggressive would have been killed by humans, and so only the ones that were bold and friendly would have been tolerated.

Friendliness caused strange things to happen in the wolves. They started to look different. Domestication gave them splotchy coats, floppy ears, wagging tails. In only several generations, these friendly wolves would have become very distinctive from their more aggressive relatives. But the changes did not just affect their looks. Changes also happened to their psychology. These protodogs evolved the ability to read human gestures.

As dog owners, we take for granted that we can point to a ball or toy and our dog will bound off to get it. But the ability of dogs to read human gestures is remarkable. Even our closest relatives-chimpanzees and bonobos-can't read our gestures as readily as dogs can. Dogs are remarkably similar to human infants in the way they pay attention to us. This ability accounts for the extraordinary communication we have with our dogs. Some dogs are so attuned to their owners that they can read a gesture as subtle as a change in eye direction.

With this new ability, these protodogs were worth knowing. People who had dogs during a hunt would likely have had an advantage over those who didn't. Even today, tribes in Nicaragua depend on dogs to detect prey. Moose hunters in alpine regions bring home 56 percent more prey when they are accompanied by dogs. In the Congo, hunters believe they would starve without their dogs.

Dogs would also have served as a warning system, barking at hostile strangers from neighboring tribes. They could have defended their humans from predators.

And finally, though this is not a pleasant thought, when times were tough, dogs could have served as an emergency food supply. Thousands of years before refrigeration and with no crops to store, hunter-gatherers had no food reserves until the domestication of dogs. In tough times, dogs that were the least efficient hunters might have been sacrificed to save the group or the best hunting dogs. Once humans realized the usefulness of keeping dogs as an emergency food supply, it was not a huge jump to realize plants could be used in a similar way.

So, far from a benign human adopting a wolf puppy, it is more likely that a population of wolves adopted us. As the advantages of dog ownership became clear, we were as strongly affected by our relationship with them as they have been by their relationship with us. Dogs may even have been the catalyst for our civilization.

Dr. Brian Hare is the director of the Duke Canine Cognition Center and Vanessa Woods is a research scientist at Duke University. This essay is adapted from their new book, The Genius of Dogs, published by Dutton. To play science-based games to find the genius in your dog, visit www.dognition.com.


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Stinkbug Threat Has Farmers Worried


Part of our weekly "In Focus" series—stepping back, looking closer.

Maryland farmer Nathan Milburn recalls his first encounter.

It was before dawn one morning in summer 2010, and he was at a gas station near his farm, fueling up for the day. Glancing at the light above the pump, something caught his eye.

"Thousands of something," Milburn remembers.

Though he'd never actually seen a brown marmorated stinkbug, Milburn knew exactly what he was looking at. He'd heard the stories.

This was a swarm of them—the invasive bugs from Asia that had been devouring local crops.

"My heart sank to my stomach," Milburn says.

Nearly three years later, the Asian stinkbug, commonly called the brown marmorated stinkbug, has become a serious threat to many mid-Atlantic farmers' livelihoods.

The bugs have also become a nuisance to many Americans who simply have warm homes—favored retreats of the bugs during cold months, when they go into a dormant state known as overwintering.

The worst summer for the bugs so far in the U.S. was 2010, but 2013 could be shaping up to be another bad year. Scientists estimate that 60 percent more stinkbugs are hunkered down indoors and in the natural landscape now than they were at this time last year in the mid-Atlantic region.

Once temperatures begin to rise, they'll head outside in search of mates and food. This is what farmers are dreading, as the Asian stinkbug is notorious for gorging on more than a half dozen North American crops, from peaches to peppers.

Intruder Alert

The first stinkbugs probably arrived in the U.S. by hitching a ride with a shipment of imported products from Asia in the late 1990s. Not long after that, they were spotted in Allentown, Pennsylvania. Since then, they've been identified in 39 other states. Effective monitoring tools are being developed to help researchers detect regional patterns.

There are two main reasons to fear this invader, whose popular name comes from the pungent odor it releases when squashed. It can be distinguished from the native stinkbug by white stripes on its antennae and a mottled appearance on its abdomen. (The native stinkbug can also cause damage but its population number is too low for it to have a significant impact.)

For one thing, Asian stinkbugs have an insatiable appetite for fruits and vegetables, latching onto them with a needlelike probe before breaking down their flesh and sucking out juice until all that's left is a mangled mess.

Peaches, apples, peppers, soybeans, tomatoes, and grapes are among their favorite crops, said Tracy Leskey, a research entomologist leading a USDA-funded team dedicated to stinkbug management. She adds that in 2010, the insects caused $37 million in damage just to apple crops in the mid-Atlantic region.

Another fear factor: Although the stinkbug has some natural predators in the U.S., those predators can't keep up with the size of the stinkbug population, giving it the almost completely unchecked freedom to eat, reproduce, and flourish.

Almost completely unchecked. Leskey and her team have found that stinkbugs are attracted to blue, black, and white light, and to certain pheromones. Pheromone lures have been used with some success in stinkbug traps, but the method hasn't yet been evaluated for catching the bugs in large numbers.

So Milburn—who is on the stakeholders' advisory panel of Leskey's USDA-funded team—and other farmers have had to resort to using some chemical agents to protect against stinkbug sabotage.

It's a solution that Milburn isn't happy about. "We have to be careful—this is people's food. My family eats our apples, too," he says. "We have to engage and defeat with an environmentally safe and economically feasible solution."

Damage Control

Research Entomologist Kim Hoelmer agrees but knows that foregoing pesticides in the face of the stinkbug threat is easier said than done.

Hoelmer works on the USDA stinkbug management team's biological control program. For the past eight years, he's been monitoring the spread of the brown marmorated stinkbug with an eye toward containing it.

"We first looked to see if native natural enemies were going to provide sufficient levels of control," he says. "Once we decided that wasn't going to happen, we began to evaluate Asian natural enemies to help out."

Enter Trissolcus, a tiny, parasitic wasp from Asia that thrives on destroying brown marmorated stinkbugs and in its natural habitat has kept them from becoming the extreme pests they are in the U.S.

When a female wasp happens upon a cluster of stinkbug eggs, she will lay her own eggs inside them. As the larval wasp develops, it feeds on its host—the stinkbug egg—until there's nothing left. Most insects have natural enemies that prey upon or parasitize them in this way, said Hoelmer, calling it "part of the balance of nature."

In a quarantine lab in Newark, Delaware, Hoelmer has been evaluating the pros and cons of allowing Trissolcus out into the open in the U.S. It's certainly a cost-effective approach.

"Once introduced, the wasps will spread and reproduce all by themselves without the need to continually reintroduce them," he says.

And these wasps will not hurt humans. "Entomologists already know from extensive research worldwide that Trissolcus wasps only attack and develop in stinkbug eggs," Hoelmer says. "There is no possibility of them biting or stinging animals or humans or feeding on plants or otherwise becoming a pest themselves."

But there is a potential downside: the chance the wasp could go after one or more of North America's native stinkbugs and other insects.

"We do not want to cause harm to nontarget species," Hoelmer says. "That's why the host range of the Asian Trissolcus is being studied in the Newark laboratory before a request is made to release it."

Ultimately, the USDA's Animal and Plant Health Inspection Service will decide whether or not to introduce the wasp. If it does, the new natural enemy could be let loose as early as next year.

Do you have stinkbugs in your area? Have they invaded your home this winter? Or your garden last summer? How do you combat them? Share your sightings and stories in the comments.


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Mars Missions: A Time Line of Success and Failure


Humans have been thinking about visiting Mars—or being visited by Martians—for more than a century. On Wednesday, a group funded by businessman Dennis Tito announced its intention to launch a manned flyby mission to Mars in 2018.

Our awareness of Mars dates back millennia, while our modern picture of the red planet emerged in the 1870s, when Italian astronomer Giovanni Schiaparelli claimed to see networks of channels (canali) through his telescope. The Italian word, mistranslated into English as "canals," helped inspire American astronomer Percival Lowell to observe Mars for decades and create detailed maps of a Martian canal system.

Lowell's work popularized the idea of Mars as a dry and dying world with canals constructed by an advanced civilization carrying life-giving water from the polar ice caps. (Related: The Psychology of Deep Space Travel.)

This romantic vision helped spur novels like War of the Worlds by H. G. Wells. But in the 20th century, Wells's fantastic sci-fi world of heat-ray-wielding Martian invaders gave way to scientific research on how humans might actually visit the red planet.

German rocket pioneer Wernher von Braun was the first to develop a practical plan for a Martian journey. In the early 1950s, while working for the U.S. government, he proposed a massive expedition involving ten 4000-ton spaceships and 70 crew members.

The envisioned Mars trip reflected von Braun's grand dream of winged shuttle rocket fleets, a giant orbiting space station, and a moon base. Beginning in 1952, Collier's magazine published eight articles on this futuristic goal, hiring artists to bring von Braun's plans to life. ("Meet One of Mars Rover Curiosity's Earthbound Twins.")

Working with von Braun, Walt Disney produced a series of television specials dramatizing human trips to orbit, the moon, and finally Mars. Cereal manufacturers introduced toy models of this proposed Martian space fleet.

More than half a century on, the dream that compelled so many Americans still seems, to many, to be just that: a dream.

So why hasn't Martian travel happened yet?

Technology and cost have been the two big sticking points.

Von Braun's plan, for its part, overlooked many barriers—prolonged effects of weightlessness, radiation from solar flares—and was grounded in a poor understanding of Mars, whose thin atmosphere makes it a far more hostile place than he knew.

The costs involved to solve such problems are immense, helping prevent Mars travel so far. But Von Braun's proposals have given rise to more than a thousand schemes from governments, companies, and private groups to reach the red planet. The NASA publication Humans to Mars, written by David S.F. Portree, chronicles these efforts. Here are highlights:

1962: Project EMPIRE. A series of studies by NASA and outside aerospace contractors, Project EMPIRE proposed a Mars flyby using the same 500-day orbit as the planned 2018 Inspiration Mars trip. The flyby was designed to allow astronauts to gain more information about the planet and return to Earth. Later plans envisioned an enormous rocket called Nova—larger than the Saturn V moon rocket—to boost five 450-foot-long (137-meter-long) ships to orbit, carrying a total of 15 crew members to Mars for an extended stay. This and other early plans assumed large manned ships would slow down by skimming off the surface of a thick Martian atmosphere, saving huge amounts of fuel.

1964: Mariner 4. This unmanned probe, the first to reach Mars, revealed a planet with a far thinner atmosphere and higher radiation levels than expected. Lowell's canals and an ancient Martian civilization were missing. Mariner revealed that human travel to Mars would be hazardous and that automated probes might perform many observations more cheaply.

1966: JAG. This plan for a 1976 mission proposed using a nuclear-powered rocket carrying four humans on a flyby around Mars. On approach, an automated probe would descend to the planet's surface, collect soil samples, then quickly rocket up to a manned ship zooming overhead. The crew would return to Earth after a 667-day voyage. Soaring Vietnam War costs killed the project, although the automated lander eventually developed into the unmanned Viking missions that successfully touched down on Mars in 1976.

1969: Post-Apollo. Hoping to exploit the first moon landing, NASA proposed an ambitious follow-on program, pitched in part by Wernher von Braun and echoing his original vision: a winged shuttle, a space station, and a large human expedition to Mars. Faced with Vietnam War costs and waning public interest in space following the moon landing, the plan was rejected, though then President Richard Nixon approved development of the space shuttle. In the following decades, unmanned craft successfully visited Mercury, Mars, Jupiter, Saturn, Uranus, and Neptune.

1989: Space Exploration Initiative. Developed during the first Bush Administration, the plan provided a framework to complete the space station, set up a lunar outpost, and mount a Mars expedition around 2010. Cost estimates soared to over $500 billion, dooming the effort.

2004: Vision for Space Exploration. This plan, hatched during the second Bush Administration, called for using technology developed for the Apollo and shuttle programs to construct a new crew vehicle, booster rocket, and heavy-lift rocket to return to the moon as early as 2015. New technologies and approaches tested on the moon, the thinking went, would lead to human trips to Mars around 2030. Most of the program was canceled for cost reasons.

2012: Red Dragon. Developed by Elon Musk's Space Exploration company, this plan proposes to send an automated "Dragon" vehicle to land on Mars in 2018, paving the way for an eventual human landing.

2013: Inspiration Mars. Proposed by Dennis Tito, the first space tourist, the idea is to seize on an unusual 2018 planetary alignment to send a male and female astronaut on a 500-day flyby around Mars. The National Geographic Society is exploring the idea of partnering with Tito's group.


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Sharks Warn Off Predators By Wielding Light Sabers


Diminutive deep-sea sharks illuminate spines on their backs like light sabers to warn potential predators that they could get a sharp mouthful, a new study suggests.

Paradoxically, the sharks seem to produce light both to hide and to be conspicuous—a first in the world of glowing sharks. (See photos of other sea creatures that glow.)

"Three years ago we showed that velvet belly lanternsharks [(Etmopterus spinax)] are using counter-illumination," said lead study author Julien Claes, a biologist from Belgium's Catholic University of Louvain, by email.

In counter-illumination, the lanternsharks, like many deep-sea animals, light up their undersides in order to disguise their silhouette when seen from below. Brighter bellies blend in with the light filtering down from the surface. (Related: "Glowing Pygmy Shark Lights Up to Fade Away.")

Fishing the 2-foot-long (60-centimeter-long) lanternsharks up from Norwegian fjords and placing them in darkened aquarium tanks, the researchers noticed that not only do the sharks' bellies glow, but they also had glowing regions on their backs.

The sharks have two rows of light-emitting cells, called photophores, on either side of a fearsome spine on the front edges of their two dorsal fins.

Study co-author Jérôme Mallefet explained how handling the sharks and encountering their aggressive behavior hinted at the role these radiant spines play.

"Sometimes they flip around and try to hit you with their spines," said Mallefet, also from Belgium's Catholic University of Louvain. "So we thought maybe they are showing their weapon in the dark depths."

To investigate this idea, the authors analyzed the structure of the lanternshark spines and found that they were more translucent than other shark spines.

This allowed the spines to transmit around 10 percent of the light from the glowing photophores, the study said.

For Predators' Eyes Only

Based on the eyesight of various deep-sea animals, the researchers estimated that the sharks' glowing spines were visible from several meters away to predators that include harbor seals (Phoca vitulina), harbor porpoises (Phocoena phocoena), and blackmouth catsharks (Galeus melastomus).

"The spine-associated bioluminescence has all the characteristics to play the right role as a warning sign," said Mallefet.

"It's a magnificent way to say 'hello, here I am, but beware I have spines,'" he added.

But these luminous warning signals wouldn't impede the sharks' pursuit of their favorite prey, Mueller's bristle-mouth fish (Maurolicus muelleri), the study suggested. These fish have poorer vision than the sharks' predators and may only spot the sharks' dorsal illuminations at much closer range.

For now, it remains a mystery how the sharks create and control the lights on their backs. The glowing dorsal fins could respond to the same hormones that control the belly lights, suggested Mallefet, but other factors may also be involved.

"MacGyver" of Bioluminescence

Several other species use bioluminescence as a warning signal, including marine snails (Hinea brasiliana), glowworms (Lampyris noctiluca) and millipedes (Motyxia spp.).

Edith Widder, a marinebiologist from the Ocean Research and Conservation Association who was not involved in the current study, previously discovered a jellyfish whose bioluminescence rubs off on attackers that get too close.

"It's like paint packages in money bags at banks," she explained.

"Any animal that was foolish enough to go after it," she added "gets smeared all over with glowing particles that make it easy prey for its predators."

Widder also points out that glowing deep-sea animals often put their abilities to diverse uses. (Watch: "Why Deep-Sea Creatures Glow.")

"There are many examples of animals using bioluminescence for a whole range of different functions," she said.

Mallefet agrees, joking that these sharks are the "MacGyver of bioluminescence."

"Just give light to this shark species and it will use it in any possible way."

And while Widder doesn't discount the warning signal theory, "another possibility would be that it could be to attract a mate."

Lead author Julien Claes added by email, "I also discovered during my PhD thesis that velvet belly lanternsharks have glowing organs on their sexual parts."

And that, he admits, "makes it very easy, even for a human, to distinguish male and female of this species in the dark!"

The glowing shark study appeared online in the February 21 edition of Scientific Reports.


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Picture Archive: Dorothy Lamour and Jiggs, Circa 1938


Dorothy Lamour, most famous for her Road to ... series of movies with Bing Crosby and Bob Hope, never won an Oscar. In her 50-plus-year career as an actress, she never even got nominated.

Neither did Jiggs the chimpanzee, pictured here with Lamour on the set of Her Jungle Love in a photo published in the 1938 National Geographic story "Monkey Folk."

No animal has ever been nominated for an Oscar. According to Academy Award rules, only actors and actresses are eligible.

Uggie, the Jack Russell terrier from last year's best picture winner, The Artist, didn't rate a nod. The equines that portrayed Seabiscuit and War Horse, movies that were best picture contenders in their respective years, were also snubbed.

Even the seven piglets that played Babe, the eponymous star of the best picture nominee in 1998, didn't rate. And the outlook seems to be worsening for the animal kingdom's odds of ever getting its paws on that golden statuette.

This year, two movies nominated in the best picture category had creatures that were storyline drivers with significant on-screen time. Neither Beasts of the Southern Wild (which featured extinct aurochs) or Life of Pi (which featured a CGI Bengal tiger named Richard Parker) used real animals.

An Oscar's not the only way for animals to get ahead, though. Two years after this photo was published, the American Humane Association's Los Angeles Film & TV Unit was established to monitor and protect animals working on show business sets. The group's creation was spurred by the death of a horse during the filming of 1939's Jessie James.

Today, it's still the only organization that stamps "No Animals Were Harmed" onto a movie's closing credits.

Editor's note: This is part of a series of pieces that looks at the news through the lens of the National Geographic photo archives.


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Picture Archive: Dorothy Lamour and Jiggs, Circa 1938


Dorothy Lamour, most famous for her Road to ... series of movies with Bing Crosby and Bob Hope, never won an Oscar. In her 50-plus-year career as an actress, she never even got nominated.

Neither did Jiggs the chimpanzee, pictured here with Lamour on the set of Her Jungle Love in a photo published in the 1938 National Geographic story "Monkey Folk."

No animal has ever been nominated for an Oscar. According to Academy Award rules, only actors and actresses are eligible.

Uggie, the Jack Russell terrier from last year's best picture winner, The Artist, didn't rate a nod. The equines that portrayed Seabiscuit and War Horse, movies that were best picture contenders in their respective years, were also snubbed.

Even the seven piglets that played Babe, the eponymous star of the best picture nominee in 1998, didn't rate. And the outlook seems to be worsening for the animal kingdom's odds of ever getting its paws on that golden statuette.

This year, two movies nominated in the best picture category had creatures that were storyline drivers with significant on-screen time. Neither Beasts of the Southern Wild (which featured extinct aurochs) or Life of Pi (which featured a CGI Bengal tiger named Richard Parker) used real animals.

An Oscar's not the only way for animals to get ahead, though. Two years after this photo was published, the American Humane Association's Los Angeles Film & TV Unit was established to monitor and protect animals working on show business sets. The group's creation was spurred by the death of a horse during the filming of 1939's Jessie James.

Today, it's still the only organization that stamps "No Animals Were Harmed" onto a movie's closing credits.

Editor's note: This is part of a series of pieces that looks at the news through the lens of the National Geographic photo archives.


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Elderly Abandoned at World's Largest Religious Festival


Every 12 years, the northern Indian city of Allahabad plays host to a vast gathering of Hindu pilgrims called the Maha Kumbh Mela. This year, Allahabad is expected to host an estimated 80 million pilgrims between January and March. (See Kumbh Mela: Pictures From the Hindu Holy Festival)

People come to Allahabad to wash away their sins in the sacred River Ganges. For many it's the realization of their life's goal, and they emerge feeling joyful and rejuvenated. But there is also a darker side to the world's largest religious gathering, as some take advantage of the swirling crowds to abandon elderly relatives.

"They wait for this Maha Kumbh because many people are there so nobody will know," said one human rights activist who has helped people in this predicament and who wished to remain anonymous. "Old people have become useless, they don't want to look after them, so they leave them and go."

Anshu Malviya, an Allahabad-based social worker, confirmed that both men and women have been abandoned during the religious event, though it has happened more often to elderly widows. Numbers are hard to come by, since many people genuinely become separated from their groups in the crowd, and those who have been abandoned may not admit it. But Malviya estimates that dozens of people are deliberately abandoned during a Maha Kumbh Mela, at a very rough guess.

To a foreigner, it seems puzzling that these people are not capable of finding their own way home. Malviya smiles. "If you were Indian," he said, "you wouldn't be puzzled. Often they have never left their homes. They are not educated, they don't work. A lot of the time they don't even know which district their village is in."

Once the crowd disperses and the volunteer-run lost-and-found camps that provide temporary respite have packed away their tents, the abandoned elderly may have the option of entering a government-run shelter. Conditions are notoriously bad in these homes, however, and many prefer to remain on the streets, begging. Some gravitate to other holy cities such as Varanasi or Vrindavan where, if they're lucky, they are taken in by temples or charity-funded shelters.

In these cities, they join a much larger population, predominantly women, whose families no longer wish to support them, and who have been brought there because, in the Hindu religion, to die in these holy cities is to achieve moksha or Nirvana. Mohini Giri, a Delhi-based campaigner for women's rights and former chair of India's National Commission for Women, estimates that there are 10,000 such women in Varanasi and 16,000 in Vrindavan.

But even these women are just the tip of the iceberg, says economist Jean Drèze of the University of Allahabad, who has campaigned on social issues in India since 1979. "For one woman who has been explicitly parked in Vrindavan or Varanasi, there are a thousand or ten thousand who are living next door to their sons and are as good as abandoned, literally kept on a starvation diet," he said.

According to the Hindu ideal, a woman should be looked after until the end of her life by her male relatives—with responsibility for her shifting from her father to her husband to her son. But Martha Chen, a lecturer in public policy at Harvard University who published a study of widows in India in 2001, found that the reality was often very different.

Chen's survey of 562 widows of different ages revealed that about half of them were supporting themselves in households that did not include an adult male—either living alone, or with young children or other single women. Many of those who did live with their families reported harassment or even violence.

According to Drèze, the situation hasn't changed since Chen's study, despite the economic growth that has taken place in India, because widows remain vulnerable due to their lack of education and employment. In 2010, the World Bank reported that only 29 percent of the Indian workforce was female. Moreover, despite changes in the law designed to protect women's rights to property, in practice sons predominantly inherit from their parents—leaving women eternally dependent on men. In a country where 37 percent of the population still lives below the poverty line, elderly dependent relatives fall low on many people's lists of priorities.

This bleak picture is all too familiar to Devshran Singh, who oversees the Durga Kund old people's home in Varanasi. People don't pay toward the upkeep of their relatives, he said, and they rarely visit. In one case, a doctor brought an old woman to Durga Kund claiming she had been abandoned. After he had gone, the woman revealed that the doctor was her son. "In modern life," said Singh, "people don't have time for their elderly."

Drèze is currently campaigning for pensions for the elderly, including widows. Giri is working to make more women aware of their rights. And most experts agree that education, which is increasingly accessible to girls in India, will help improve women's plight. "Education is a big force of social change," said Drèze. "There's no doubt about that."


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Meet One of Mars Rover Curiosity’s Earthbound Twins


Like its twin that's busy exploring Mars aboard the rover Curiosity, the device known as SAM II spends its days as if it were 200 million miles away, in a very different environment than our own.

Temperatures around the instrument plunge to minus 130ºF (-90°C), the air pressure is one percent of Earth's, and the atmosphere it sits in consists largely of carbon dioxide.

But this second SAM—short for Sample Analysis on Mars—resides in suburban Maryland, inside a tightly controlled chamber where it plays a little-known but essential role as a test instrument for the Curiosity mission to Mars. (Watch: How Curiosity took a self-portrait.)

And for a short time last month, this microwave-size "test bed" SAM was out of its deep freeze for repairs and upgrades, offering a rare peak into exactly what it takes to keep a rover and its scientific instruments alive and well on Mars.

Simply put, SAM is the most complex and sophisticated suite of scientific equipment to ever land on another celestial body.

The gold-covered box holds two tiny cylinder ovens that can vaporize Mars's rocks and soil at temperatures up to 1800°F (1,000 °C). Three instruments (spectrometers) then identify and analyze the gases produced by the ovens, as well as those collected from the Martian atmosphere. Some six miles (nine kilometers) of electrical wire connect these and many other parts together.

SAM's task constitutes a primary aim of Curiosity's mission: investigating whether Mars preserves the chemical ingredients needed for life, including organic carbon. (Related: Intriguing new evidence of a watery past on Mars.)

SAM has already analyzed some Martian soil and will very soon get its first taste of Martian rock, dug out with a drill last week and crushed into powder. A pre-programmed examination of that rock powder—a first-of-its-kind procedure—is scheduled to begin inside SAM shortly. (Related: Curiosity completes first full drill for Martian rock samples.

Maryland SAM in the Operating Room

But for the SAM on Mars to operate safely and properly, it needs the Maryland SAM (a 99 percent duplicate) as a test bed.

Every command sent to the instrument on Mars must first be run through the twin on Earth to make sure it doesn't confuse the operating system, doesn't open a wrong valve, doesn't set into motion a fatal cascade of events. So keeping the test-bed SAM in near-perfect shape is essential to Curiosity's success.

Yet some parts or connections have failed in recent months, requiring less-than-ideal workarounds. And when the SAM team recently devised additional ways to further improve their creation, they decided to bring it in for repairs.

Which is why test-bed SAM was out of its chamber last month, laid out on a gurney in a clean room at the NASA Goddard Space Flight Center in Greenbelt, Maryland.

Several days before, the liquid nitrogen piped into SAM II's chamber to keep it cold had been turned off. Myriad pipes and tubes going in were shut down. The near-vacuum pressure inside the chamber—which is the size of a washing machine and wrapped in aluminum foil—had been changed to Earth conditions.

The big chamber door (which would have exerted some 10,000 pounds, or about 4,500 kilograms, of force) was swung open.

SAM II's lustrous gold plating, needed to regulate temperatures and keep the instrument as clean as possible, had been removed, exposing the warren of intricately packed equipment and wiring inside.

In a Mylar-draped section of the room, two of the men who put both SAMs together were poking and prodding, vacuuming and tightening its insides. In their head-to-toe white cover-ups, they looked like surgeons in the OR.

One of them, Oren Sheinman, is a lead designer and builder of the two SAMs. His repair involved a heat pipe for the tunable laser spectrometer—an instrument Sheinman designed to sniff the Mars air for gases such as carbon-based methane, which could be a sign of past or present life.

Problems with SAM's heat pipe had made it difficult to ensure that the new computer instructions going up to Mars were accurate and effective, so Sheinman and colleague Bob Arvey had to find a work-around.

Speaking from behind the Mylar screen, Sheinman said that what they had created was actually similar to some spacecraft he had worked on. "Not in terms of guidance and propulsion," he said, "but in terms of system issues and sheer complexity."

"With SAM, the difficult part mechanically was packaging, because it isn't really an instrument, but an instrument suite," he said.

Discovery Requires Complexity

SAM was already the largest and heaviest instrument that Curiosity would carry, but it needed to be as small as possible to make room for Curiosity's other equipment.

Fortunately, the hardware Sheinman was working on sat near the outside of the SAM configuration; fixing a piece deeper inside would have required what he called an "excavation."

For Arvey, the primary repair job involved his specialty, the miles of wire. Because SAM has high-temperature wires to supply the ovens and low temperature wires for the instruments, all the wiring had to be crimped together rather than connected with welds.

One of those crimps, or "getters," had failed some time ago, and it too had to be replaced.

Arvey said he needed all of his 40-plus years of experience in wiring space-bound equipment (to Venus, Jupiter, Titan, and Mars) to lay out the electrical rigging of SAM.

"Everything we did in building SAM had to be made up new," he said.

It was SAM principal investigator Paul Mahaffy who decided to open up the chamber, and he says his rationale was more improvement than repair.

While the several malfunctioning parts were making life difficult, his primary goal was to better stabilize the test-bed SAM so the team could send up commands that would allow Mars SAM to make more sensitive measurements.

Curiosity is a "discovery-driven" mission, Mahaffy said, and that means demands placed on the faraway rover and its instruments are ever changing.  The result is a constant process of tweaking, upgrading and modifying as scientists and engineers learn about Mars and look to devise ways to follow new leads.

Everyone Needs a Test Bed

The Goddard test bed is hardly the only one used for Curiosity.

The home institutions of the principal investigator for all ten Curiosity instruments have their test beds, and their results have to be squared with the entire Curiosity system, headquartered at the Jet Propulsion Laboratory in Pasadena, California.

JPL has its "Mars yard," where duplicate Curiosity rovers are put through their paces—everything from climbing a steep incline to approaching and drilling a rock.

Using the drill, for instance, involves more than a hundred discrete commands, and they have been put through their paces at the yard in advance of Curiosity's first ever Mars drilling.

"It's kind of unexpected and occasionally funny, but the test beds tend to come up with more problems than the actual equipment on Mars," said Curiosity mission manager Michael Watkins.

Since the equipment and instruments are virtual duplicates, Watkins said it's not an issue of quality. Rather, problems arise because the equipment is made to operate under Mars atmospheric and gravity conditions, which are difficult to entirely reproduce on Earth.

The test equipment is also used far more frequently and aggressively than what's on the actual Curiosity.

The constant testing slows a mission down at times, and after six months on Mars the rover has traveled only about a quarter mile, or less than half a kilometer.

But it has been a productive trip. Since landing on Mars in early August, Curiosity has identified a once fast-flowing stream bed on the planet, found tantalizing but unconfirmed signs of organic materials, and has drilled into low-lying bedrock and found grey (rather than the usual Martian red) rock inside.

The rover's travels on Mars are officially set to continue until the summer of 2014, but if Curiosity and its instruments remain healthy, all involved expect it will operate for several years beyond that.

With that kind of time frame in mind, the SAM team recently arranged to have its busy test bed moved to a building that has a supply of liquid nitrogen just outside a back door.

Before that, researchers and technicians had to roll large, heavy canisters of the gas long distances into a different test room. Hardly ideal for a test bed that's likely to be busy for a long time to come.

Marc Kaufman is working on a book about Curiosity and Mars for National Geographic Books.


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Pictures: Artifacts Provide Clues to Life in Early Christchurch

Photograph courtesy Jaden Harris, Underground Overground Archaeology
 
 
 

A tiny container for Holloway's ointment, less than two inches (five centimeters) wide, came from what was probably a brick-lined basement on Madras Street under a multistory modern commercial building.

British patent medicine entrepreneur Thomas Holloway began to advertise his ointment in 1837, claiming it would cure an impressive list of ailments—"Bad Legs, Bad Breasts, Burns, Bunions, Bite of Mosquitoes and Sandflies, Coco-bay, Chiego-foot, Chilblains, Chapped Hands, Corns (Soft), Cancers, Contracted and Stiff Joints, Elephantiasis, Fistulas, Gout, Glandular Swellings, Lumbago, Piles, Rheumatism, Scalds, Sore Nipples, Sore Throats, Skin Diseases, Scurvy, Sore Heads, Tumours, Ulcers, Wound(s), Yaws."

("Coco-bay" is a Jamaican word for a form of leprosy. "Chiego-foot" is a Trinidadian term that describes a foot covered in chigger bites.)

Holloway moved his company several times in London. "The changing address and the subtle differences in the wording and images that appear on these pots are what enable them to be dated," said Watson. The address on this particular pot—533 Oxford Street, London—indicates that it was made between 1867 and 1881.

Published February 21, 2013

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Florida Python Hunt Captures 68 Invasive Snakes


It's a wrap—the 2013 Python Challenge has nabbed 68 invasive Burmese pythons in Florida, organizers say. And experts are surprised so many of the elusive giants were caught.

Nearly 1,600 people from 38 states—most of them inexperienced hunters—registered for the chance to track down one of the animals, many of which descend from snakes that either escaped or were dumped into the wild.

Since being introduced, these Asian behemoths have flourished in Florida's swamps while also squeezing out local populations of the state's native mammals, especially in the Everglades. (See Everglades pictures.)

To highlight the python problem, the Florida Fish and Wildlife Conservation Commission and its partners launched the 2013 Python Challenge, which encouraged registered participants to catch as many pythons as they could between January 12 and February 10 in state wildlife-management areas within the Everglades.

The commission gave cash prizes to those who harvested the most and longest pythons.

Frank Mazzotti, a wildlife ecologist at the University of Florida and scientific leader for the challenge, said before the hunt that he would consider a harvest of 70 animals a success—and 68 is close enough to say the event met its goals.

It's unknown just how many Burmese pythons live in Florida, but catching 68 snakes is an "exceptional" number, added Kenneth Krysko, senior herpetologist at the Florida Museum of Natural History in Gainesville.

Snakes in the Grass

Finding 68 snakes is impressive, experts say, since it's so hard to find pythons. For one, it's been unusually warm lately in Florida, which means the reptiles—which normally sun themselves to regulate their body temperature—are staying in the brush, making them harder to detect, Krysko said.

On top of that, Burmese pythons are notoriously hard to locate, experts say.

The animals are so well camouflaged that people can stand right next to one and not notice it. "It's rare that you get to see them stretched out—most of the time they're blending in," said Cheryl Millett, a biologist at the Nature Conservancy, a Python Challenge partner.

What's more, the reptiles are ambush hunters, which means they spend much of their time lying in wait in dense vegetation, not moving, she said.

That's why Millett gave the hunters some tips, such as looking along the water's edge, where the snakes like to hang out, and also simply listening for "something big moving through the vegetation."

Even so, catching 68 snakes is "actually is a little more than I expected," said Millett.

No Walk in the Park

Ruben Ramirez, founder of the company Florida Python Hunters, won two prizes in the competition: First place for the most snakes captured—18—and second place for the largest python, which he said was close to 11 feet (3.4 meters) long. The biggest Burmese python caught in Florida, nabbed in 2012, measured 17.7 feet (5.4 meters).

"They're there, but they're not as easy to find as people think," said Ramirez. "You're not going to be stumbling over pythons in Miami." (Related blog post: "What It's Like to Be a Florida Python Hunter.")

All participants, some of whom had never hunted a python before, were trained to identify the difference between a Burmese python and Florida's native snakes, said Millett. No native snakes were accidentally killed, she said.

Hunters were also told to kill the snakes by either putting a bolt or a bullet through their heads, or decapitating them-all humane methods that result "in immediate loss of consciousness and destruction of the brain," according to the Python Challenge website.

Ramirez added that some of the first-time or amateur hunters had different expectations. "I think they were expecting to walk down a canal and see a 10-foot [3-meter], 15-foot [4.5-meter] Burmese python. They thought it'd be a walk in the park."

Stopping the Spread

Completely removing these snakes from the wild isn't easy, and some scientists see the Python Challenge as helping to achieve part of that goal. (Read an opposing view on the Python Challenge: "Opinion: Florida's Great Snake Hunt Is a Cheap Stunt.")

"You're talking about 68 more animals removed from the population that shouldn't be there—that's 68 more mouths that aren't being fed," said the Florida museum's Krysko. (Read about giant Burmese python meals that went bust.)

"I support any kind of event or program that not only informs the general public about introduced species, but also gets the public involved in removing these nonnative animals that don't belong there."

The Nature Conservancy's Millett said the challenge had two positive outcomes: boosting knowledge for both science and the public.

People who didn't want to hunt or touch the snakes could still help, she said, by reporting sightings of exotic species to 888-IVE-GOT-1, through free IveGot1 apps, or www.ivegot1.org.

Millett runs a public-private Nature Conservancy partnership called Python Patrol that the Florida wildlife commission will take on in the fall. The program focuses not only on eradicating invasive pythons but on preventing the snake from moving to ecologically sensitive areas, such as Key West.

Necropsies on the captured snakes will reveal what pythons are eating, and location data from the hunters will help scientists figure out where the snakes are living—valuable data for researchers working to stop their spread.

"This is the most [number of] pythons that have been caught in this short of a period of time in such an extensive area," said the University of Florida's Mazzotti.

"It's an unprecedented sample, and we're going to get a lot of information out of that."


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New Ancient Members of Whale Family Found

Jane J. Lee in Boston


The ancestors of modern baleen whales—including the ancient forbears of blue whales (Balaenoptera musculus) and humpbacks (Megaptera novaeangliae)—just got four new relatives.

Scientists announced Sunday that they have discovered the new species thanks in large part to a construction crew in southern California.

The researchers discovered 11 whale species at the site, said Meredith Rivin, a paleontologist at California State University in Fullerton, including the four new species.

The newly identified ancient animals belong to the group including baleen whales, named for the frayed blades of fingernail-like material hanging down from the roof of their mouths, which they use to strain seawater for food.

The four new species of ancient baleen whales had teeth—unlike their current relatives—and are not direct ancestors to modern baleen whales, said Rivin. They represent a transitional step and are related to the animals that would eventually give rise to the whales we know today.

During work on a new road through Laguna Canyon (map) near Los Angeles in 2000, construction crews uncovered an outcrop littered with whale fossils around 17 to 19 million years old.

By that time, Rivin said, toothed baleen whales "were supposed to have been extinct for about 5 million years or so, and we got a huge diversity of them."

Not only were they not extinct, she said, but it appears that the lineage was doing well at the time.

Before these finds, there weren't any examples of toothed baleen whales from around the world during this time period, called the early Miocene, said Rivin.

Paleontologists accompanying the Southern California crew eventually uncovered hundreds of whale bones and over 30 whale skulls over a five-year period.

Three of the new species are relatively small, about the size of modern-day dolphins, said Rivin.

One of the larger species, a 30-foot (nine-meter) whale in the genus Morawanocetus, is similar to another ancient whale species, Llanocetus denticrenatus, which was thought to have gone extinct 35 million years ago. (Read about a mud-grubbing toothed baleen whale.)

Rivin discussed the newly discovered species of ancient toothed baleen whales at the annual American Association for the Advancement of Science meeting in Boston.

She plans to publish papers on three of the four toothed baleen whale species later this year.

The fourth one she's still trying to extract fully from the rock, although she's been able to uncover enough to know that this whale is unlike anything she's ever seen before. Its teeth have very long roots that bulge up from the bone. Rivin plans to keep chipping away at the rock surrounding the fossil until she can study the entire specimen.


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Confirmed: Dogs Sneak Food When People Aren't Looking


Many dog owners will swear their pups are up to something when out of view of watchful eyes. Shoes go missing, couches have mysterious teeth marks, and food disappears. They seem to disregard the word "no."

Now, a new study suggests dogs might understand people even better than we thought. (Related: "Animal Minds.")

The research shows that domestic dogs, when told not to snatch a piece of food, are more likely to disobey the command in a dark room than in a lit room.

This suggests that man's best friend is capable of understanding a human's point of view, said study leader Juliane Kaminski, a psychologist at the U.K.'s University of Portmouth.

"The one thing we can say is that dogs really have specialized skills in reading human communication," she said. "This is special in dogs." (Read "How to Build a Dog.")

Sneaky Canines

Kaminski and colleagues recruited 84 dogs, all of which were more than a year old, motivated by food, and comfortable with both strangers and dark rooms.

The team then set up experiments in which a person commanded a dog not to take a piece of food on the floor and repeated the commands in a room with different lighting scenarios ranging from fully lit to fully dark.

They found that the dogs were four times as likely to steal the food—and steal it more quickly—when the room was dark. (Take our dog quiz.)

"We were thinking what affected the dog was whether they saw the human, but seeing the human or not didn't affect the behavior," said Kaminski, whose study was published recently in the journal Animal Cognition.

Instead, she said, the dog's behavior depended on whether the food was in the light or not, suggesting that the dog made its decision based on whether the human could see them approaching the food.

"In a general sense, [Kaminski] and other researchers are interested in whether the dog has a theory of mind," said Alexandra Horowitz, head of the Dog Cognition Lab at Barnard University, who was not involved in the new study.

Something that all normal adult humans have, theory of mind is "an understanding that others have different perspective, knowledge, feelings than we do," said Horowitz, also the author of Inside of a Dog.

Smarter Than We Think

While research has previously been focused on our closer relatives—chimpanzees and bonobos—interest in dog cognition is increasing, thanks in part to owners wanting to know what their dogs are thinking. (Pictures: How smart are these animals?)

"The study of dog cognition suddenly began about 15 years ago," Horowitz said.

Part of the reason for that, said Brian Hare, director of the Duke Canine Cognition Lab and author of The Genius of Dogs, is that "science thought dogs were unremarkable."

But "dogs have a genius—years ago we didn't know what that was," said Hare, who was not involved in the new research. (See pictures of the the evolution of dogs, from wolf to woof.)

Many of the new dog studies are variations on research done with chimpanzees, bonobos, and even young children. Animal-cognition researchers are looking into dogs' ability to imitate, solve problems, or navigate social environments.

So just how much does your dog understand? It's much more than you—and science—probably thought.

Selectively bred as companions for thousands of years, dogs are especially attuned to human emotions—and, study leader Kaminski said, are better at reading human cues than even our closest mammalian relatives.

"There has been a physiological change in dogs because of domestication," Duke's Hare added. "Dogs want to bond with us in ways other species don't." (Related: "Dogs' Brains Reorganized by Breeding.")

While research reveals more and more insight into the minds of our furry best friends, Kaminski said, "We still don't know just how smart they are."


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Pictures: What the Presidents Brought Home

Photograph by Bill Ray, Time Life Pictures/Getty Images

When paleontologist Paul Olsen (pictured left, in 1970 at 17 years old) first started looking for dinosaurs in 1967, he never dreamed that he'd end up the subject of White House memos between President Richard Nixon and his senior advisers.

Or that one of the dinosaur footprints he discovered would find its way into a presidential collection.

But that's exactly what happened when Olsen and his friend Tony Lessa (right) successfully lobbied for the creation of a park in 1970 near Livingston, New Jersey (map).

The future park, located in a quarry owned by Walter Kidde Precision Instruments, was a budding paleontologist's dream.

The area was covered in dinosaur footprints, such as ones made by Eubrontes gigantis (pictured), and some of them were more than 200 million years old.

"The footprints are very well preserved in that particular spot," said Olsen, now at Columbia University in New York. And the arrangement of some of them—many small footprints associated with one larger set—indicated behaviors that included parental care, he said.

It took Olsen and Lessa two and a half years to get the area designated as a park, but once they did, an Olsen family friend started writing letters to the White House to see if the boys could meet the President.

"[Presidential speechwriter] William Safire said he didn't want President Nixon to be associated with the concept of a dinosaur," said Olsen. The White House staff discussed this while dealing with the Vietnam War, going so far as to write memos on the situation, he said.

Olsen and Lessa never got their meeting with the President. But Nixon ended up sending the teenagers presidential commendations.

Olsen sent the President a cast of the E. gigantis footprint as a thank you. The cast now resides at the Nixon Presidential Library and Museum in Yorba Linda, California.

The actual footprint fossils, stored in a shed at the park, have walked off. "No one knows what happened to them," Olsen said.

February 17, 2013

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Picture Archive: Making Mount Rushmore, 1935-1941

Photograph from Rapid City Chamber of Commerce/National Geographic

There's no such thing as Presidents' Day.

According to United States federal government code, the holiday is named Washington's Birthday, and has been since it went nationwide in 1885.

But common practice is more inclusive. The holiday expanded to add in other U.S. presidents in the 1960s, and the moniker Presidents' Day became popular in the 1980s and stuck. It may be that George Washington (b. February 22, 1732) andAbraham Lincoln (b. February 12, 1809) still get the lion's share of attention—and appear in all the retail sale ads—on the third Monday in February, but the popular idea is that all 44 presidents get feted.

Mount Rushmore is a lot like that one day a year writ large—and in granite. It's carved 60 feet (18 meters) tall and 185 feet (56 meters) wide, from Washington's right ear to Lincoln's left.

The monument's sculptor, Gutzon Borglum, grew up in Idaho, a first-generation American born to Danish parents. He studied art in France and became good friends with Auguste Rodin. Borglum mostly worked in bronze, but in the early 1910s he was hired to carve the likenesses of Confederate leaders into Stone Mountain in Georgia.

He was about to be fired from that job for creative differences about the same time that a South Dakota historian named Doane Robinson had an idea. Robinson wanted to have a monument carved into the Black Hills of South Dakota, maybe Western historical figures like Chief Red Cloud and Lewis and Clark, each on their own granite spire. (Plan a road trip in the Black Hills.)

Robinson hired Borglum and gave him carte blanche. Borglum was looking for something with national appeal, so he chose to depict four presidents: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln.

Borglum wanted to represent the first 150 years of the nation's history, choosing four presidents as symbols of their respective time periods. He took a tour of western South Dakota, searching for an ideal canvas.

The sculptor was looking for three things: a surface strong enough to sculpt, a mountain big enough to hold several figures, and a mountain face that received morning sunlight. Mount Rushmore fit the bill and was already part of a national forest, so it was easy to set aside as a national memorial.

Work started in 1927. Calvin Coolidge attended the dedication ceremony. It took 14 years to finish the carving, conducted mostly in summertime because of the area's harsh winters.

There were approximately 30 workers on the mountain at any give time. In total about 400 had worked on it by the time the monument was finished. Though the project involved thousands of pounds of dynamite and perilous climbs, not a single person died during the work.

Borglum himself died of natural causes in 1941, though, just six months before the project was declared "closed as is" by Congress that Halloween. His son Lincoln—named for his father's favorite president—took over.

In the photo above, a worker refines the details of Washington's left nostril.

About 90 percent of the mountain was carved using dynamite, which could get within 3 to 5 inches (8 to 13 centimeters) of the final facial features. For those last few inches, workers used what was known as the honeycomb method: Jackhammer workers pounded a series of three-inch-deep holes followed up by chiselers who knocked off the honeycomb pieces to get the final shape. Then carvers smoothed the "skin's" surface.

—Johnna Rizzo

February 16, 2013

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Why We Walk … and Run … And Walk Again to Get Where We're Going


You have to get to a bus stop to catch the once-an-hour express ... or to a restaurant to meet a friend ... or to a doctor's office. You've got maybe a half a mile to cover and you're worried you'll be late. You run, then you stop and walk, then run some more.

But wait. Wouldn't it be better to run the whole way?

Not necessarily.

A new study by an assistant professor of mechanical engineering at Ohio State University tests the theory that people subconsciously mix walking and running so they get where they need to. The idea is that "people move in a manner that minimizes energy consumption," said the professor, Manoj Srinivasan.

Srinivasan asked 36 subjects to cover 400 feet (122 meters), a bit more than the length of a football field. He gave them a time to arrive at the finish line and a stopwatch. If the deadline was supertight, they ran. If they had two minutes, they walked. And if the deadline was neither too short nor too far off, they toggled between walking and running.

The takeaway: Humans successfully make the walk-run adjustment as they go along, based on their sense of how far they have to go. "It's not like they decide beforehand," Srinivasan said. (Get tips, gear recommendations, and more in our Running Guide.)

The Best Technique for "the Twilight Zone"

"The mixture of walking and running is good when you have an intermediate amount of time," he explained. "I like to call it 'the Twilight Zone,' where you have neither infinite time nor do you have to be there now."

That ability to shift modes served ancient humans well. "It's basically an evolutionary argument," Srinivasan said. A prehistoric human seeking food would want to move in a way that conserves some energy so that if food is hard to find, the hunter won't run out of gas—and will still be able to rev it up to escape predators.

The study, published on January 30 in the Journal of the Royal Society Interface, doesn't answer that question of how we make such adjustments.

Runners: Take a Break if You Need It

The mix of walking and running is also something that nonelite marathoners are familiar with. Covering 26.2 miles might take less of a toll if the runner stops running from time to time, walks a bit, then resumes a jogging pace. "You use less energy overall and also give yourself a bit of a break," Srinivasan noted. (Watch: An elite marathoner on her passion for running.)

One take-home lesson is: Runners, don't push it all the time. A walk-run mix will minimize the energy you expend.

Lesson two: If you're a parent walking with your kid, and the kid lags behind, then runs to catch up, then lags again, the child isn't necessarily trying to annoy you. Rather, the child is perhaps exhibiting an innate ability to do the walk-run transition.

Potential lesson three: The knowledge that humans naturally move in a manner that minimizes energy consumption might be helpful in designing artificial limbs that feel more natural and will help the user reduce energy consumption.

The big question for Manoj Srinivasan: Now that he has his walk-run theory, does he consciously switch between running and walking when he's trying to get somewhere? "I must admit, no," he said. "When I want to get somewhere, I just let the body do its thing." But if he's in a rush, he'll make a mad dash.

"Talk to you tomorrow," he signed off in an email to National Geographic News. "Running to get to teaching now!"


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Asteroid Impacts:10 Biggest Known Hits


There's one physical connection that isn't going down after Valentine's Day this year: Earth and asteroid.

The asteroid known as 2012 DA14 will narrowly miss Earth this Friday, the closest asteroid flyby on record. But the planet has not always been so lucky.

Earth's craters are enduring testaments to direct asteroid hits. And though millions-in some cases billions-of years of erosion have made it difficult to determine the exact size of the meteorites, there is a general scientific consensus around the world's largest craters, which mark the largest asteroid impacts.

Here are the ten biggest known:

1. Vredefort Crater

Asteroid impact date: Estimated 2 billion years ago

Location: Free State, South Africa

Specs: Also known as the Vredefort Dome, the Vredefort crater has an estimated radius of 118 miles (190 kilometers), making it the world's largest known impact structure. This crater was declared a UNESCO World Heritage Site in 2005.

2. Sudbury Basin

Asteroid impact date: Estimated 1.8 billion years ago

Location: Ontario, Canada

Specs: The Sudbury Basin is considered one of largest impact structures on Earth, with an estimated diameter of 81 miles (130 kilometers). Dating back 1.8 billion years, it is also one of the oldest known impact structures in the world.

3. Acraman Crater

Asteroid impact date: Estimated 580 million years ago

Location: South Australia, Australia

Specs: Located in what is now Lake Acraman, this impact structure has an estimated diameter of 56 miles (90 kilometers).

4. Woodleigh Crater

Asteroid impact date: Estimated 364 million years ago

Location: Western Australia, Australia

Specs: This crater is not exposed at the surface and has led to many discrepancies regarding its actual size. Reports on its diameter vary from 25 to 75 miles (40 to 120 kilometers).

5. Manicouagan Crater

Asteroid impact date: Estimated 215 million years ago

Location: Quebec, Canada

Specs: This impact crater formed what is now Lake Manicouagan. Even with erosion, it's considered one of the largest and best-preserved craters on Earth, with an estimated diameter of 62 miles (100 kilometers).

6. Morokweng Crater

Asteroid impact date: Estimated 145 million years ago

Location: North West, South Africa

Specs: Located near the Kalahari Desert in South Africa, this crater contained the fossilized remains of the meteorite that created it.

7. Kara Crater

Asteroid impact date: Estimated 70.3 million years ago

Location: Nenetsia, Russia

Specs: Now greatly eroded, the Kara crater is a non-exposed impact structure in Russia. Some have claimed that the impact structure actually consists of two adjacent craters: the Kara and the Ust-Kara crater.

8. Chicxulub Crater

Asteroid impact date: Estimated 65 million years ago

Location: Yucatán, Mexico

Specs: Located on the Yucatán Peninsula in Mexico, many scientists believe that the meteorite that left this crater caused or contributed to the extinction of the dinosaurs. Estimates of its actual diameter range from 106 to a whooping 186 miles (170 to 300 kilometers), which if proved right could mean it's the biggest.

9. Popigai Crater

Asteroid impact date: Estimated 35.7 million years ago

Location: Siberia, Russia

Specs: Russian scientists claim that this crater site contains trillions of carats of diamonds, making it one of the largest diamond deposits in the world. These diamonds have been referred to as "impact diamonds."

10. Chesapeake Bay Crater

Asteroid impact date: Estimated 35 million years ago

Location: Virginia, United States

Specs: Discovered in the early 1980s, the Chesapeake Bay Crater is located approximately 125 miles (201 kilometers) from Washington, D.C. Some estimates suggest this crater is 53 miles (85 kilometers) wide.


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Owl Monkeys Shed Light on Evolution of Love


It may not seem like monkey business, but emotional bonds in animals such as primates may have evolved into love as we know it.

Take owl monkeys, tiny tropical tree-dwellers that treat every day like it's Valentine's Day. A male and a female stick together as long as possible, never cheat, and never "divorce" their mates—extremely unusual behavior, even among people. (Also see "Male Monkeys Wash With Urine to Attract Females?")

Sometimes, though, young adult owl monkeys that can't find mates—monkeys that scientists call floaters—pick vicious fights with established pairs, eventually kicking one of them out.

Now, new research shows that the monkeys forced to take on new partners have fewer babies than owl monkeys that haven't been broken up, said Eduardo Fernandez-Duque, a biological anthropologist at the University of Pennsylvania in Philadelphia who led a new study on owl monkey relationships.

The results show how monogamy helps owl monkeys—and may even shed light on how human relationships evolved.

"Call it love, call it friendship, call it marriage—there is something in our biology that leads to this enduring, emotional bond between two individuals that is widespread among human societies," Fernandez-Duque said in a statement.

Trouble in Paradise

Only about five percent of mammals are monogamous, and the phenomenon most often arises when both parents are needed to raise offspring, as in the case of people.

With owl monkeys, fathers take on most of the childcare after a baby is born, relying on the mother only for milk. (See video: "Owl Monkey Fathers Know Best?")

But floaters—which Fernandez-Duque and colleagues first noticed in 2003 in Argentina's Chaco region (map)—can spell trouble in paradise.

Drawing on nearly two decades of observations of 18 owl monkey groups, the team discovered that pairs that stay intact produce 25 percent more babies than monkeys in severed pairs.

The exiled animal from those broken relationships, meanwhile, is usually injured and often dies.

Since the team studied more than 150 animals, "I felt very confident that what he was telling us is a real phenomenon—it's not a flash in the pan," noted Patricia Wright, who was one of the first people to study owl monkeys in the 1980s.

"He had the goods on the animals. I was really excited about that," said Wright, an anthropologist at Stony Brook University in New York.

Wright said she was personally pleased that the study reinforced findings that owl monkeys stay true to one another unless forced to separate.

"I knew that these little monkeys didn't fool around," she said.

Chemistry of Love

Why monkeys that are broken up have fewer babies is unknown, though Fernandez-Duque suspects there's an emotional component. (See more pictures of all-star animal dads.)

Just as a man and a woman need time to get to know each other and form a deep connection, so do owl monkeys. So when a marauding monkey enters into a new relationship, there's a delay in mating—usually about a year, Fernandez-Duque  said.

In fact, pair bonding in monogamous animals, such as owl monkeys, may be "sort of evolutionary antecedent to love in humans," said Larry Young, a behavioral neuroscientist at Emory University in Atlanta and author of the new book The Chemistry Between Us: Love Sex and the Science of Attraction.

Young, who studies the brain chemistry of love and emotion, does most of his research on monogamous prairie voles.

Though human love is a rich emotion reflective of our advanced brains, he said, "the foundation of that emotion is very similar to the neuromechanisms that are causing the bond between these two prairie voles."

For instance, experiments have shown that if a vole loses its partner, the "widowed" animal shows depressive symptoms—measured by a lack of willingness to escape a dangerous situation.

According to Young, our brains are in the love seat, so to speak: The organs "have evolved the mechanism to produce an emotional attachment," he said.

That attachment is spurred by oxytocin—produced during intimate contact in both people and animals—and dopamine, which is responsible for feelings of exhilaration and happiness.

So, many splendored as it is, love, he said, "is really the result of a cocktail of chemicals."

The owl monkey study was published January 23 in the journal PLoS ONE.


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What Killed Dinosaurs: New Ideas About the Wipeout


New insights about the asteroid thought to have killed off the dinosaurs suggest it may have just been the final blow, and that the reptiles were already suffering from a finicky climate prompted by volcanic eruptions long before the meteorite struck.

"The [asteroid] impact was the coup de grace," Paul Renne, a geologist at the University of California, Berkeley, said in a statement.

The research, detailed in the February 8 issue of the journal Science, adds to the ongoing scientific debate over what exactly killed off the dinosaurs.

That debate, which once revolved around the question of whether the culprit was an asteroid or volcano-induced climate changes, has evolved to consider the possibility that perhaps multiple environmental factors were involved.

Renne and his team recently determined the most precise date yet for the asteroid strike, which occurred in the Yucatan peninsula in what is now Mexico.

Using a high-precision dating technique on tektites—pebble-sized rocks formed during meteorite impacts—from Haiti that were created during the event, the team concluded that the impact occurred 66,038,000 years ago—slightly later than previously thought.

When error limits are taken into account, the new date is the same as the date of the extinction, the team says, making the events simultaneous.

Renne said the new findings, should lay to rest any remaining doubts about whether an asteroid was a factor in the dinosaurs' demise.

"We have shown that these events are synchronous to within a gnat's eyebrow," he said, "and therefore the impact clearly played a major role in extinctions."

That is not to say, however, that the asteroid—which carved out the so-called Chicxulub crater—was the sole cause of the dinosaurs' extinction.

Evidence now suggests massive volcanic eruptions in India that predated the asteroid strike also played a part, triggering climate changes that were already killing off some dinosaur groups.

For example, "nobody has ever found a non-avian dinosaur fossil exactly at the impact layer," Renne said in an email. "Hence, strictly speaking, the non-avian dinosaurs"—those dinosaurs unrelated to birds—"may have already gone extinct by the time of the impact."

Death From the Skies

The idea that volcanism was responsible for the dinosaurs' demise actually predates the impact theory, and it fits well with what is known about Earth's other mass extinction events.

"Many of the other mass extinctions have been found to co-occur with large-scale volcanic eruptions," said Heiko Pälike, a paleoceanographer at the University of Bremen in Germany.

But in the 1980s, father-son team Luis and Walter Alvarez, a physicist and planetary scientists, respectively, presented a bold new theory.

After discovering that a layer of clay that's found throughout the world and that coincided with the end of the Cretaceous period is enriched in iridium—an element rare on Earth but common in space rocks—they proposed that a meteorite wiped out the dinosaurs.

"As the impact theory took hold, especially with the more physical scientists ... the volcanists lost ground," Renne explained.

The impact theory gained further momentum in the 1990's, when scientists discovered a 110-mile (180-kilometer) wide impact crater in the Yucatan peninsula that dated to the boundary between the Cretaceous and Tertiary periods—the so-called KT boundary—when the dinosaurs disappeared.

The crater's size indicated that whatever created it was roughly 6 miles (10 kilometers) in diameter.

An asteroid of that size striking the Earth would have had devastating consequences, including destructive pressure waves, global wildfires, tsunamis, and a "rain" of molten rock reentering the atmosphere.

Additionally, "much additional particulate matter would have stayed afloat in the atmosphere for weeks, months, perhaps years, blocking incoming solar radiation and thus killing plant life and causing catastrophic drops in temperatures," explained Hans-Dieter Sues, a paleontologist at the Smithsonian National Museum of Natural History in Washington, D.C.

Hybrid Theory for Dinosaur Extinction

The once-abandoned volcanism theory has seen a revival of sorts in recent years, however, as a result of fresh insights about a period of sustained ancient volcanic activity in India and the discovery that dinosaur diversity may have already been declining before the asteroid strike.

The debate now is "whether the Chicxulub impact was the 'smoking gun,' as many researchers claim," Sues said, "or one of several causative factors, kind of like 'Murder on the Orient Express.'"

Renne belongs to the camp that thinks a series of volcanic eruptions in India that produced ancient lava flows known as the Deccan Traps caused dramatic climate variations, including long cold snaps, that may have already been culling the dinosaurs before the asteroid struck.

"It seems clear that volcanism alone, if on a sufficiently massive and rapid scale, can trigger extinctions," Renne said. "Thus my view that the impact was probably the final straw, but not the sole cause."

Unanswered questions

The new hybrid theory still has some major questions it must answer, however, like precisely how much the Indian volcanic eruptions affected the dinosaurs.

"Some people say if you look at the eruption of Mount Pinatubo [in 1991], it cooled the Earth for a short period of time due to the aerosol and the dust that was ejected," Pälike said.

But "others say in the long run volcanoes probably pump more carbon dioxide into the atmosphere and actually warm the planet, at least temporarily."

It's also unclear how the Deccan Traps eruptions were spread out in time. "We know that they started a few million years before the end of the Cretaceous and lasted for several million years after, extending even beyond the [asteroid impact]," Pälike said.

"However, some people have suggested that there were clusters of eruptions that happened within a span of a few tens of thousands of years."

Knowing the timing of the eruptions is important, Pälike added, because if they were happening close to the end of the Cretaceous, it's more likely they played a role in the dinosaurs' extinction than if most of the eruptions happened two million years before.

Pälike thinks that more precise dating of the volcanic ash layers in India could help answer some of the remaining questions: "That's the next step of the puzzle."

Pinning down the cause of the dinosaurs' extinction isn't just of academic interest, said Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History at the University of Florida.

"It's important for us to understand how ecosystems respond to big perturbations," Bloch said, "whether it's gradual climate change or a catastrophic event. These are all things we have to think about as humans on the planet today."


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Year of the Snake: The Serpent Behind the Horoscope


On February 10, people all around the world will ring in the Lunar New Year with paper lanterns and firecrackers. At the heart of it all sits the snake, a slithery reptile feared for its sharp fangs and revered for its undeniable charm. (Watch videos of some of the world's deadliest snakes.)

Those born in the Year of the Snake are said to be intelligent and quick thinking, but they can also be dishonest and prone to show off. Though based on Chinese astrology, some of these traits are similar to characteristics of the actual serpent.

Snakes are known to be great at outsmarting their predators and prey. Their colorful, patterned skin makes them some of the best tricksters in the animal kingdom. And despite a bad rap as frightening creatures, snakes never fail to fascinate scientists, explorers, and zoo-goers. (See pictures of snakes.)

With more than 3,400 recognized species, snakes exhibit incredible diversity in everything from behavior and habitats to skin colors and patterns.

"As a vertebrate lacking in limbs, all snakes look largely like other snakes, yet they succeed in tremendous diversity in multiple directions," said Andrew Campbell, herpetology collections manager at the University of Kansas Biodiversity Institute.

To usher in the Year of the Snake, Campbell and herpetologist Dennis Ferraro at University of Nebraska-Lincoln weigh in on some of the snake's qualities that the Chinese zodiac predicts people born this year will have.

Horoscope: Snakes have an innately elegant personality but can also be ostentatious at times.

In Nature: Snakes come in all different colors, patterns, and textures, making them some of nature's most visually stunning creatures.

According to Campbell, the utility of their coloring falls into two main categories: to use as camouflage and to warn predators to stay away.

Among the most beautiful are the emerald tree boa (Corallus caninus)—whose vibrant green body is decorated with white stripes resembling lightning bolts—and the Brazilian rainbow boa (Epicrates cenchria), characterized by its iridescent skin and the large black rings down its back.

For some snakes, the diversity in color occurs within the same species, which is why Ferraro tells his student not to identify snakes by colors. For example, the polymorphic bush viper (Atheris squamigera), many of which are green, also come in shades of yellow, orange, red, and blue, as captured in photographer Guido Mocafico's "Serpent Still Life" photo series.

Horoscope: The snake is known to be the master seducer of the Chinese zodiac.

In Nature: Female garter snakes (Thamnophis) have all the luck with the gentlemen.

When a female garter snake is ready to mate, she announces it by producing chemicals called pheromones. Males, upon encountering the scent, immediately come crawling out and gather around the female in a large, wriggling "mating ball."

The competition intensifies when a male passing by the ball tries to fool the others by producing a scent that mimics that of the female, said Ferraro.

As soon as his rivals are led off in the wrong direction, the trickster slides right in. In areas with smaller populations of garter snakes, each ball consists of about 12 males and one female.

But in places like Manitoba, Canada, where garter snakes travel to certain areas to mate after coming out of hibernation, a mating ball can have thousands of males and only a hundred females.

Horoscope: Though snakes don't often tell lies, they will use deception when they feel it's necessary and they think they can get away with it.

In Nature: When it comes to using trickery to catch dinner, or to hide from predators, snakes are no amateurs.

Their sneaky techniques range from tricking fish to swim right into their mouths, to playing dead when threatened, to using their wormlike tails to lure in prey.

The most cunning of them all is the two-headed snake. To protect against a sneak attack from behind, the two-headed snake's tail looks just like its head. While the business end looks for food, the snake coils up its body and rests its tail on top to look like it is on guard.

The tail can even mimic the behavior of a retreating snake to trick predators into thinking they're going face-to-face with their opponent.

Horoscope: When snakes get down to work, they are organized and highly efficient, and they work quickly and quietly.

In Nature: While snakes are often perceived as lazy, Campbell said people are mistaken. "What we perceive as shy, lazy, or inactive is really efficiency," he said.

"On average, they are bigger than other lizards and can build a lot of body mass. They do that by being efficient in feeding and traveling." In other words, snakes don't move very much because they don't have to.

When it comes to food, snakes catch prey that are significantly larger than them so they can eat less frequently. This reduces the time they spend hunting and thus makes them less vulnerable to falling victim to a predator themselves.

For Campbell, the most impressive hunter is the eastern diamondback rattlesnake (Crotalus Adamanteus), which is able to hunt and kill its prey very quickly using venom, so it doesn't have to travel far. "Because they don't have to do that, they can become relatively large and heavy, being able to build up body mass and not having to spend that energy hunting."

Horoscope: Snakes are charming, with excellent communication skills.

In Nature: For snakes, their visual and auditory senses don't mean much when it comes to communicating with each other.

Instead, they use their sense of smell and the chemicals produced by their musk glands. Unlike mammals, a snake picks up scent through the forks of its tongue.

When the snake retracts its tongue, it inserts the forks into grooves in an olfactory organ located at the roof of its mouth. Depending on which fork picks up a stronger scent, the snake knows in which direction to go when looking for prey or a mate.

It's when snakes are threatened that they use sight and sound, said Ferraro. Rattlesnakes, for example, shake their tails, making a loud rattling noise to ward off predators.


Read More..

Year of the Snake: The Serpent Behind the Horoscope


On February 10, people all around the world will ring in the Lunar New Year with paper lanterns and firecrackers. At the heart of it all sits the snake, a slithery reptile feared for its sharp fangs and revered for its undeniable charm. (Watch videos of some of the world's deadliest snakes.)

Those born in the Year of the Snake are said to be intelligent and quick thinking, but they can also be dishonest and prone to show off. Though based on Chinese astrology, some of these traits are similar to characteristics of the actual serpent.

Snakes are known to be great at outsmarting their predators and prey. Their colorful, patterned skin makes them some of the best tricksters in the animal kingdom. And despite a bad rap as frightening creatures, snakes never fail to fascinate scientists, explorers, and zoo-goers. (See pictures of snakes.)

With more than 3,400 recognized species, snakes exhibit incredible diversity in everything from behavior and habitats to skin colors and patterns.

"As a vertebrate lacking in limbs, all snakes look largely like other snakes, yet they succeed in tremendous diversity in multiple directions," said Andrew Campbell, herpetology collections manager at the University of Kansas Biodiversity Institute.

To usher in the Year of the Snake, Campbell and herpetologist Dennis Ferraro at University of Nebraska-Lincoln weigh in on some of the snake's qualities that the Chinese zodiac predicts people born this year will have.

Horoscope: Snakes have an innately elegant personality but can also be ostentatious at times.

In Nature: Snakes come in all different colors, patterns, and textures, making them some of nature's most visually stunning creatures.

According to Campbell, the utility of their coloring falls into two main categories: to use as camouflage and to warn predators to stay away.

Among the most beautiful are the emerald tree boa (Corallus caninus)—whose vibrant green body is decorated with white stripes resembling lightning bolts—and the Brazilian rainbow boa (Epicrates cenchria), characterized by its iridescent skin and the large black rings down its back.

For some snakes, the diversity in color occurs within the same species, which is why Ferraro tells his student not to identify snakes by colors. For example, the polymorphic bush viper (Atheris squamigera), many of which are green, also come in shades of yellow, orange, red, and blue, as captured in photographer Guido Mocafico's "Serpent Still Life" photo series.

Horoscope: The snake is known to be the master seducer of the Chinese zodiac.

In Nature: Female garter snakes (Thamnophis) have all the luck with the gentlemen.

When a female garter snake is ready to mate, she announces it by producing chemicals called pheromones. Males, upon encountering the scent, immediately come crawling out and gather around the female in a large, wriggling "mating ball."

The competition intensifies when a male passing by the ball tries to fool the others by producing a scent that mimics that of the female, said Ferraro.

As soon as his rivals are led off in the wrong direction, the trickster slides right in. In areas with smaller populations of garter snakes, each ball consists of about 12 males and one female.

But in places like Manitoba, Canada, where garter snakes travel to certain areas to mate after coming out of hibernation, a mating ball can have thousands of males and only a hundred females.

Horoscope: Though snakes don't often tell lies, they will use deception when they feel it's necessary and they think they can get away with it.

In Nature: When it comes to using trickery to catch dinner, or to hide from predators, snakes are no amateurs.

Their sneaky techniques range from tricking fish to swim right into their mouths, to playing dead when threatened, to using their wormlike tails to lure in prey.

The most cunning of them all is the two-headed snake. To protect against a sneak attack from behind, the two-headed snake's tail looks just like its head. While the business end looks for food, the snake coils up its body and rests its tail on top to look like it is on guard.

The tail can even mimic the behavior of a retreating snake to trick predators into thinking they're going face-to-face with their opponent.

Horoscope: When snakes get down to work, they are organized and highly efficient, and they work quickly and quietly.

In Nature: While snakes are often perceived as lazy, Campbell said people are mistaken. "What we perceive as shy, lazy, or inactive is really efficiency," he said.

"On average, they are bigger than other lizards and can build a lot of body mass. They do that by being efficient in feeding and traveling." In other words, snakes don't move very much because they don't have to.

When it comes to food, snakes catch prey that are significantly larger than them so they can eat less frequently. This reduces the time they spend hunting and thus makes them less vulnerable to falling victim to a predator themselves.

For Campbell, the most impressive hunter is the eastern diamondback rattlesnake (Crotalus Adamanteus), which is able to hunt and kill its prey very quickly using venom, so it doesn't have to travel far. "Because they don't have to do that, they can become relatively large and heavy, being able to build up body mass and not having to spend that energy hunting."

Horoscope: Snakes are charming, with excellent communication skills.

In Nturea: For snakes, their visual and auditory senses don't mean much when it comes to communicating with each other.

Instead, they use their sense of smell and the chemicals produced by their musk glands. Unlike mammals, a snake picks up scent through the forks of its tongue.

When the snake retracts its tongue, it inserts the forks into grooves in an olfactory organ located at the roof of its mouth. Depending on which fork picks up a stronger scent, the snake knows in which direction to go when looking for prey or a mate.

It's when snakes are threatened that they use sight and sound, said Ferraro. Rattlesnakes, for example, shake their tails, making a loud rattling noise to ward off predators.


Read More..