The Why Files The Science Behind The News Sat, 31 Jan 2015 01:36:21 +0000 en-US hourly 1 In the mind’s eye of a bird brain Thu, 29 Jan 2015 21:45:01 +0000 More »]]>
In the mind’s eye of a bird brain
A photoshopped chick stands in front of an illustrated array of cards with different numbers of red dots, arranged low to high from left to right. Thought bubble extending from chick reads, "left means less, right means more.
A three-day-old chick is the same age and strain as the birds in the study shows the general idea of the mental number line: Small numbers go on the left, large on the right.
Chick photo: Rosa Rugani, University of Trento; Composite: The Why Files

Imagine two cards side by side. One shows three squares, the other 10. Odds are you’ve placed the card with three squares to the left of the one with 10.

Now imagine cards showing 10 and 20 squares. Odds are the 10-square card is now on the left.

Congratulations! You have just demonstrated an innate human tendency called the mental number line: Smaller to the left, larger to the right.

In a study this week in Science 1, Italian researchers report the same trait in 3-day-old chickens.

By placing a worm behind the cards, they induced the chicks to choose which of two identical cards to visit first. And lo and behold, the chick visits the card that is correctly placed in that small-to-the-left-large-to-the-right number line.

Just like people:

If the training number was five and the test number was two, they visited the two that was on the left in more than 70 percent of tests.

If the training number was five and the test number was eight, they visited the eight on the right, again in more than 70 percent of tests.

Chick flick shows mental number line

Adapted by The Why Files from original from Rosa Rugani, University of Trento

“Chicks chose respectively the right or the left side of their visual space depending on the numbers seen at test being greater or smaller than the number seen at training,” according to first author Rosa Rugani, a fellow with the Center for Mind/Brain Sciences at the University of Trento, Italy.

We can’t intuit what the birds were thinking — or even if they were thinking — but the best way to explain it is that the birds were somehow more comfortable when number sequence matched their mental number line. Or maybe they expected that number in its number-line location, and so they responded faster.

Lining up the numbers

The idea of a mental number line originated in the late 1800s, Rugani said, when Viennese psychologist Francis Galton “first showed that humans describe and think of numbers as being represented on a mental number line oriented from left (small numbers) to right (large numbers).”

The mental number line is everywhere!

Tape measure: hjl, calipers: Morpheu5

Could the left-to-right order reflect the pattern we see in the placement of words on the page? Perhaps. Readers of Arabic, which reads right-to-left, tend to envision small numbers on the right. However, readers of Hebrew (another right-to-left script) who also read English show the small-on-left pattern, suggesting that this is the innate pattern, although it can sometimes be overcome.

Math: It’s an animal thing

If you’re astonished that chicks have such a number sense, Rugani says Clark’s nutcrackers and rhesus macaque monkeys also show some form of “number-space mapping.”

And that’s not the limit, she adds. “The capability to solve numerical tasks is widespread among all tested species (e.g. frogs, honey bees, fish, birds, etc.).” Some animal mathematical performances resembles those of human adults who are prevented from using language.

That, Rugani says, “suggests that animals’ numerical cognition originates from pre-linguistic precursors that are widespread in all the animal kingdom,” and that the mapping of numbers “is widespread among all species.”

From photo by Tina Asami Newton

In a commentary2 in Science, Peter Brugger, of the department of neurology at University Hospital Zurich, wrote that the Rugani results “show that newborn chicks can understand both relative and absolute quantities. They also suggest that the brain may be prewired in how it relates numbers to space.”

Comprehending numbers can help an animal identify a larger food source or survive, Rugani wrote us. “Imagine a situation in which an animal can observe for a safe point of view a predator that enters a den. Later it sees another predator enter the same den. Thereafter a single predator exits. Also imagine that our animal wants to enter the den, but only if the animal can solve simple summations and subtractions will it survive.”

Add it up, she says, and “Numerical competence and the association of numbers with space originate from very ancient precursors.”

So next time you are addled by algebra, don’t blame it again on your ancient ancestors!

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. Number-space mapping in the newborn chick resembles humans’ mental number line, Rosa Rugani et al, Science, 30 January 2015
  2. Chicks with a number sense, Peter Brugger, Science, 30 January 2015
  3. Our brains have a map for numbers.
  4. Kids’ mental number lines reveal math memory.
  5. Learned, not innate human intuition: Study finds twist to the story of the number line.
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Crazy about comets! Thu, 22 Jan 2015 22:03:39 +0000 More »]]>
Comet season for keeps!
Full view of comet 67P before it was boarded by the lander shows the two large lobes that make up the Manhattan-sized space rock.
It’s an icy, stony world! This composite was stitched from four photos taken by Rosetta 19 miles (31 kilometers) from the center of comet 67P/Churyumov-Gerasimenko on Nov. 20, 2014. One pixel shows 10 feet, or three meters.

With the astonishing success of the European mission to comet 67P, comets are back in the news. Rosetta the spaceship sent its slave spaceship, Philae, to land on 67P on Nov. 12, 2014. After Philae quit bouncing up and down in the comet’s microgravity, it landed in a place with limited sunlight. With insufficient electric power from its solar panels, the lander got down to business for about a day, and worked until it exhausted its batteries.

What have we learned from the European Space Agency’s Rosetta mission, which began traveling toward Comet 67P/Churyumov-Gerasimenko 10 years ago?

Not too dense! Density measurements released today by Rosetta scientists match well with those taken from Deep Impact in 2005, says comet expert Michael A’Hearn, of the University of Maryland. The Deep Impact mission fired a missile at Comet Tempel 1 and studied the results. To figure the density of the comet’s nucleus, they measured how fast junk lofted by the impact fell back under the comet’s gravity. Since gravity is a function of the object’s mass, the technique gives “a direct measure of gravity,” A’Hearn says. Using this and another method, Deep Impact scientists calculated a density of less than 0.5 grams per cubic centimeter.

That’s odd, since comets are believed to be a mix of ice (density 1) and dirt or rock (density 2 to 3). “This says the nucleus has to be very porous,” says A’Hearn, Deep Impact’s principal investigator. Gratifyingly, Rosetta direct measure of density, “got a number that’s in remarkably good agreement with Tempel 1.”

The unavoidable conclusion is that comets “are mostly hollow,” A’Hearn says, and likely were formed by individual “comitesimals” – small chunks that joined together (accreted) through a “very gentle” process. The low density also casts doubt on the theory that comets are fragments of large objects. (We’ll dig into more results from Deep Impact shortly.)

Front, side and top views of comet 67P showing theoretical boundaries based on the comet's highly heterogeneous surface features: 19 have been defined.
Nicolas Thomas, et al, Science1.

My beautiful regions! The highly variable surface of 67P is shown in a just-released study, showing at least 19 different regions, named for Egyptian gods. Based on appearance, the scientists found, “dust-covered terrains, brittle materials with pits and circular structures, large-scale depressions, smooth terrains, and exposed consolidated surfaces.” The study may lay to rest a common assumption about comets, the authors wrote. “The concept of cometary nuclei as rather uniform, pristine, proto-planetesimals that may have been subjected to collisional processing is persistent, despite evidence of regional differences” seen on other comets. The current observations, they added, “have revealed an irregular-shaped, processed nucleus surface with morphologically diverse units.” In other words, just like galaxies, stars and planets, objects that were once assumed to be similar and ultimately boring seem to be anything but. Viva la cometology!

Weird water: Even before Philae’s epic comet-touchdown, mother-ship Rosetta snared some provocative data2 about frozen water on the comet.

Photo taken from the Rosetta orbiter of the Philae lander on the distant comet before the orbiter lost visual contact. The lander sits in front of a looming and scraggy cliff.
The Philae lander of the European Space Agency’s “Rosetta mission landed safely on the surface of Comet 67P, as shown in the first pix from Philae’s camera (notice one of the lander’s feet?) Early results were just announced from Philae’s stableful of scientific instruments. What’s up with the science of Cometology, class of 2015?

What is the origin of Earth’s water, the key to life? Earth was hotter than blazes for millions of years as the sun and its planets condensed from a fiery glob of gas and dust, so any water would have evaporated. Planetary scientists have thought that our water might have been delivered by comets, which are, indeed, dirty snowballs.

Hydrogen, an element with one proton and one electron, has a rarer, heavier isotope called deuterium, which also contains one neutron. But Rosetta, like some (but not all) other comet craft, found a deuterium-to-hydrogen (D-H) ratio totally out of whack with the oceanic ratio. The D-H ratio is thought to be a relic of the comet’s heritage, which depends on its birthplace:

“Oort Cloud” comets formed around Uranus and Neptune, and then moved far beyond Pluto.

“Jupiter family comets,” including 67P, formed in the Kuiper Belt further from the sun, then moved inward toward Jupiter’s orbit.

The D-H ratio, A’Hearn says, should reflect temperatures when the water formed, so each of the major comet families should have a characteristic D-H ratio that reflects its origin. The frigid conditions found farther from the sun produce a higher deuterium ratio. But if the Jupiter family comets all formed in the Oort cloud, as believed, why do comet studies show them having such a range of D-H ratios?

A second problem begs for solution: the new D-H ratio calculated for the Jupiter family comet 67P, is three times that found in Earth’s oceans, meaning that those comets may not have delivered water to Earth. Perhaps some or all of the water came from asteroids, even though they have a much lower percentage of water than comets.

The isotopic evidence of cometary heritage exemplifies the role of comets as messengers from the aborning solar system. The ensuing 4-plus billion years have completely and repeatedly transformed our planet, yet barely changed the comets.

Why are some comets visible to the naked eye and not others? From Earth, the brightest comets are those with small perihelion (closest pass around the Sun) and perigee (closest pass around the Earth), so the comet is both better illuminated and closer to stargazers. Humans have witnessed these extra bright comets for as long as we’ve been looking up. This diagram shows theoretical orbital positions of some of the brightest (and most engaging) comets of the last millennium.

Comet stages Mars flyby

Comet Siding Spring passed Mars on Oct. 19, 2014. Each pixel represents 138 meters in images taken from a distance of 138,000 kilometers. Siding Spring originated in the Oort Cloud, a spherical shell of objects located about 5,000 to 100,000 times as far from the sun as Earth. With their super-long orbits, Oort Cloud comets are considered “long-period comets.”

Top: Original image, showing nucleus and bright part of surrounding coma (dust that travels with the comet). This image provided the first good data for the size of the nucleus of a long-period comet. This one is about 0.5 kilometers across.

Bottom: Image doctored to show full extent of coma.

Rollover image to view a composite showing this first view of a comet’s close passage past Mars. (The comet is thousands of time dimmer than Mars, so separate exposures were needed.) Credit for rollover 1: Siding spring nucleus + coma Mars Reconnaissance Orbiter, NASA/JPL/University of Arizona. Credit for rollover 2: Comet siding spring and Mars 6690 NASA, ESA, PSI, JHU/APL, STScI/AURA

A colorized image of the 'string of pearls' comet formation showing how one large comet can break up to form several smaller comets.

In the planetary nursery

Comets live in other solar systems: This year, researchers reported changes in light from the star Beta Pictoris as hundreds of comets passed between the star and Earth. The comets came in two varieties: The “dried up” comets emitted little of the gas spewed by the younger, more active comets. One set of observations3 reminded the researchers of a “string of pearls” in our solar-system shown here, a series of small comets that formed when comet 73P/Schwassmann–Wachmann 3 broke up. The 23-million year old planetary system at Beta Pictoris likely resembles our turbulent, combative solar system when it was full of youthful vigor and devoid of the tranquility of age! (Recall that planetary systems form when gas and dust condense around a young star. Countless objects collide, sometimes joining and other times obliterating each other.) Image: NASA/JPL-Caltech/W. Reach (SSC/Caltech)

Making a deep impact

A payload from NASA’s Deep Impact spacecraft committed suicide against comet Tempel 1 in July 2005. In this photo taken 67 seconds later, light from the collision saturated the camera’s detector. Sunlight shows ridges, scalloped edges and possibly ancient impact craters on the comet’s surface. Rollover left: in one of the last photos from the impactor, arrow shows the direction of travel; yellow spot shows the target. Rollover right: a plume of comet-crud was kicked up in a photo taken about 700 seconds after the impact.

The mix of ices from water, carbon dioxide and carbon monoxide blasted from the top 25 meters of the comet matched what is normally released from the surface by sunlight, says principal investigator Michael A’Hearn. “That was contrary to predictions. At least for that part of one comet, 90 percent of the theories were wrong.” Although Tempel 1 was homogenous with depth, it was not from side to side. If the same differences from place to place existed in the youthful comet, A’Hearn says, “That means the comitesimals that came together to make the nucleus probably formed at somewhat different distances from the sun and migrated” to places where they met and bonded. Image #1: NASA/JPL-Caltech/UM. Image #2: NASA/JPL-Caltech/University of Maryland

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. [The morphological diversity of comet 67P/Churyumov-Gerasimenko, Nicolas Thomas, et al., SCIENCE, VOL347, ISSUE 6220 (2015)]
  2. 67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio, K. Altwegg, Science Express, 11 December 2014 / Page 1 / 10.1126/science.1261952
  3. Two families of exocomets in the b Pictoris system, F. Kiefer et al, Nature 2014, doi:10.1038/nature13849
  4. Memorable comets of the past.
  5. Fun comet facts.
  6. Rosetta’s comet: Seasons are changing!
  7. Rosetta’s new to do: hunt for sugars in comet ice?
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Birds cross Himalayas Thu, 15 Jan 2015 20:32:59 +0000 More »]]>
Birds cross Himalayas
Photo of a white goose with black-tipped wings in flight over the Mongolian Steppe.
A bar-headed goose on the wing.
Photo: Nyambayar Batbayar

When bar-headed geese migrate across the spine of the Himalayas, they follow the terrain, roller-coaster style, rather than fly a straight-line path from ridge to ridge. This flight path features far more climbing, yet a study published today in Science shows that it’s considerably more efficient than the straight-line course.

To look at how these geese make the long, high-altitude flight between India and Mongolia, Charles Bishop, a senior lecturer at the University of Bangor in the United Kingdom, and a group of collaborators implanted (and later removed) devices that tracked flights of about 15 hours each. (The entire transit of the mountains typically takes 50 to 70 hours.)

The best measure of metabolic activity — and energy output — is oxygen consumption, which cannot be measured on a flying bird. To assess how the birds were powering their flight, the research instrument measured:

Colored relief map of South Asia showing elevation relief. Colors range from green (low elevation) in parts of India to gray and white (high elevation) across the Tibetan Plateau. Map overlain with arrows showing the flight path individual geese take on the journey from India to their breeding grounds in Mongolia.
Map and relief cross-section of South Asia shows the migratory flight of bar-headed geese. The high-flyer soars south from the Mongolian steppe, over the peaks of the Tibetan plateau, to the lowlands of southern India, and returns north.
Map by The Why Files, adapted from L. A. Hawkes et al., 2012.

heart rate

vertical acceleration: the rate of climb and rise with each wing beat

wingbeat frequency (derived from vertical acceleration)

location (based on GPS measurements)

Bar-headed goose research team poses for a group photo while holding a few tolerant, banded geese
The field research team, photographed in Mongolia.
Photo of team by Nyambayar Batbayar

My heart, my oxygen

In previous lab work with bar-headed geese, Bishop found that oxygen consumption changed according to the square of the change in heart rate. For this study, he extended the relationship backward to wing beat: On average, a 5 percent rise in wing beat increased heart rate by 19 percent and oxygen consumption by 41 percent.

Thus a small change in wing beat has major consequences for metabolism and power output.

Other calculations, based vertical acceleration and wingbeat, independently confirmed the birds’ exertion level. “We know that our approximation of body power was reasonable … because it correlated with a totally independent variable, heart rate, which is correlated with oxygen consumption,” Bishop told us. “So power input and output correlated nicely.”

The studies of energetics explained the goose’s surprising preference for the roller-coaster strategy. Even though they did more climbing, they exerted less energy than they would have needed on a course with far less climbing.


The answer, Bishop says, lies in the drop in air pressure and density with altitude, which makes each wing stroke less efficient. By staying as low as possible, the geese save energy and also breathe denser air that contains more oxygen.

Air pressure could also explain the surprisingly large amount of climbing done at night or in the early morning. “It’s maybe 20° Celsius colder, and that makes the air denser. Staying in denser air reduces the flight cost because it’s easier to generate lift and thrust.”

3-D line graph showing altitudinal change in a single goose's flight over a stretch of mountainous terrain. The goose's flight closely resembles a cross-section of peaks and valleys due to the bird's affinity for staying near the ground surface.
To take the high road, or the low? Bar-headed geese opt for a ground-hugging flight across mountainous terrain, despite the additional climbing of their roller-coaster route.
Diagram by the Why Files, adapted from Charles M. Bishop et al1.

Here’s a surprise: Although there were times when the geese seemed to “coast” (flap with less force, particularly during tailwinds and updrafts), there was no evidence of gliding — flying without flapping. “There were some dramatic cases where there was a massive climb rate with either no increase in heart rate, or a decrease, while they were climbing three times faster than the normal rate,” Bishop says.

Close-up photo of dozens huddled together with the conspicuous black
Group of bar-headed geese in Mongolia
Photo: Charles Bishop

Those updrafts are stronger near the ground, Bishop adds, supplying another physical reason to stay low. He says the updraft advantage is roughly equal to the benefit that geese derive from flying in a Vee formation, which results from pressure changes that trail off the leading bird’s wing. (Bar-headed geese fly in Vees, Bishop says, but it’s not known whether they use Vee formation for their high-altitude mountain transits.)

Bar-headed geese “are specialists in high-altitude flight,” Bishop says, and have been tracked up to 7,290 meters (4.5 miles). Nonetheless, instead of staying high until the mountains are passed, “they throw the altitude away to reduce the overall cost.”

We asked about the evolutionary implications of this study, and he told us, “This does confirm that they behave in a very intelligent way. Nature once again has shown us that animals tend to move toward the most economical way of doing things that gives the best long-term survival option.”

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. The roller coaster flight strategy of bar-headed geese conserves energy during Himalayan migrations, Charles M. Bishop et al, Science, 16 Jan. 2015
  2. The paradox of extreme high-altitude migration in bar-headed geese.
  3. The most extreme migration on earth?
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Body-cams: Solution to police-civilian violence? Thu, 08 Jan 2015 22:30:33 +0000 More »]]>
Body-cams: Solution to police-civilian violence?
A uniformed police officer holds his body-worn camera for a photo-op.
A Minnesota police officer sports a chest-mounted body camera.
Photo: crayfisher

New York City is in turmoil in the wake of the July 17, 2014, death of Eric Garner at the hands of city police. On Dec. 3, demonstrations broke out after a grand jury declined to prosecute the officers. Then, on Dec. 20, two police officers were murdered in their car by a 28-year-old with a long criminal record as vengeance for Garner’s death. At the funerals, police have turned their backs on Mayor Bill de Blasio.

The death of Michael Brown, 18, from police gunshots in Ferguson, Mo., on Aug. 9, had already highlighted the outsize death toll among African-Americans in “police-involved shootings.”

Could police body-cameras, which record tense meet-ups between police and civilians, avert some confrontations and improve behavior on both sides? President Obama, for one, has advocated much wider use to reduce deaths among unarmed civilians.

Cameras seem promising, but remember that Garner’s death only aroused such a furious reaction because his last minutes were captured on a bystander’s cell-phone video. Despite this frightening footage — and even after the medical examiner labeled Garner’s death “homicide” — the district attorney declined to prosecute the police who took him down in a chokehold.

Photograph of several men and women filling an urban street while marching and wielding protest signs.
Protesters march against police brutality in New York City on Dec 13th, 2014.

As the protests and counter-protests continued in New York, we noticed a new, controlled study1 showing that body-cameras reduced the use of force and complaints against the police in Railto, Calif.

Body-cams are only the latest type of camera to be used in policing, and as we set out to explore the science of the video surveillance devices used in law enforcement, we realized why the California study was so noteworthy: Scientific studies on cameras in law enforcement are scarce. Indeed, A 2014 study2 of body-cams concluded that, “The overwhelming theme from this review is the lack of available research on the technology.”

And that’s doubly true for studies published in peer-reviewed journals.

What’s a camera good for?

The use of body-cams, car-cams and stationary cameras to enforce laws and document police behavior are justified as a means to:

deter crime

provide better evidence for prosecution

moderate aggressive behavior of civilians and officers alike

defend police against unfounded accusations of brutality

monitor officer behavior to ensure accountability and professional standards

Cameras may simply remind both sides that evidence of any wayward behavior will be gathered, but they can also invoke a mechanism called “social surveillance.” This is an idea from social psychology that people are more likely to follow behavioral norms — to act as they should — when someone is watching.

So what do we know about cops and cameras?

A 3-D graph showing the numbers of police use-of-force and public complaints from 2009 to 2013. Both categories decreased following the introduction of body-worn cameras to the police force.
Rialto police recorded more than 43,000 contacts with the public per year, with the year of the body-cam experiment resulting in fewer accounts of use-of-force and filed complaints. Notice this occurred for officers with and without cameras.
Adapted from Barak Ariel et al. 3

2014: Body-cam study shows benefits, raises more questions

The new study just mentioned, touted as the first controlled experiment of body-cams, ran for one year in Railto, a city of 100,000 east of Los Angeles.

The 115 police officers in Railto work 54 shifts per week; during the experiment, half of the shifts wore HD body-cams, and the other half did not. The experiment had the cooperation of police chief William Farrar, a co-author of the study.

For organizational and statistical reasons, each officer took part in both the control and experimental wings, meaning they wore the cams on some shifts, but not others.

Officers were instructed to “film” during any interaction with the public aside from interactions with informants or related to a sexual assault on a minor. The cameras were visible, but officers were also told to announce their presence when an interaction with the public began. At the end of each shift, audio and color video was downloaded into a web-based evidence management system.

The study defined use of force as involving pepper spray, baton, Taser, dog bite or gunshot — anything stronger than a “compliance hold” (a wrestling technique that causes pain at a joint or pressure point). The researchers focused on the use of force, and neither measured the amount of force nor whether it was justified.

The results were almost too good to be true: compared to the prior year, use of force declined by 58 percent. Citizen complaints dropped by 88 percent.

Dash cam video shows a Texas police officer using a stun gun on a 76-year-old man during a routine traffic stop. The officer was later fired for breach of department conduct and policies. KDVR (Denver)

Those plunging numbers, however, beg for explanation, as serious declines appeared in both the camera-equipped and camera-free shifts. The study authors proposed “a spillover effect” as an explanation. “The effect of being observed during experimental shifts diffused to control [non-camera] shifts,” they wrote. By modifying “the perception of individuals about what socially acceptable behavior should be in police-public interactions,” even officers who were not wearing a camera “changed their responses.”

Evidence in criminology “is clearly suggestive of social processes that could explain the reduction in use of force beyond the manipulation,” they wrote. “Peer pressure, social desirability, deterrence, leadership, perceptions of danger and crowd influence … could lead officers to control or not control themselves.”

Despite at least one emailed interview request to each of the three authors, none responded. But it’s fair to say that even before their study was published in the scientific journal, it was being used to justify wider police use of body-cams.

2001: In-car cameras

The new study added to a scanty record of study of cameras, crime, policing and police behavior. We located a study4 of dash cameras on state police cars, written in 2001, when the cameras were already mounted in 72 percent of state-police patrol cars.

The study, based on site visits, surveys and focus groups, found that

33 percent of officers reported that cameras caused them to feel safer on the job

48 percent “reported that citizens have become less aggressive after learning the event was being recorded”

70 percent reported that the cameras had little or no affect on their job performance

93 percent said video evidence from dash cams had exonerated an officer after a civilian complaint

Photo of a building roof with three rectangular cameras fixed in different vantage points
Surveillance cameras on the corner of a building. Their effectiveness depends on placement — and on the boredom and sleepiness of whoever is monitoring them!
Photo: Hustvedt

2009: Stationary video cameras

Mounted cameras — the kind that helped finger two suspects in the Boston Marathon bombing — have become a fact of life in cities. A 2009 analysis5 of 41 systems, mainly in the United Kingdom, but also in the United States, Sweden and elsewhere, found a modest, 16 percent reduction in crime, with almost all of the improvement coming from a 51 percent reduction in six “car parks” (parking lots) in the United Kingdom.

20 studies in city or town centers produced a non-significant, 7 percent reduction in crime

Nine studies in public housing also produced a 7 percent, non-significant reduction in crime

Fourteen of the 15 studies that showed some benefit were in the U.K., a trend-setter in city-wide surveillance

A district attorney shows video of officers checking the ID of a homeless man. When he pulls a knife on them, they give chase and eventually shoot him. The DA explains why the officers are not charged, based partly on the video evidence.
Video: Lancaster Newspapers, Inc.

2011: The three-cities study

The first hurdle in evaluating a surveillance system is surprisingly tough: choosing a basis for comparison. Another section of the same city (or a similar part of a different city) may have different rates of crime or aggressive behavior by police or civilians. If you compare the same area before and after the cameras are connected when the background crime rate is changing, how much of the effect you see is really attributable to the cameras?

With those concerns in mind, what does a 2011 study6 tell us about surveillance cameras installed during the mid-2000s in Chicago, Baltimore and Washington, D.C.?

After more than 50 cameras were installed in downtown Baltimore, violent crime went down 23 percent, and total crime, down 25 percent. However, crime also declined 30 percent in areas within 1,000 feet of the cameras. (Neighboring areas are always of concern due to fear that the cameras may just budge crime sideways without actually reducing it.) Furthermore, the 35 percent decrease in on-street larceny started one year after camera installation. If cameras caused this effect, why the delay?

In the Greenmount section of Baltimore, a 20 percent decline in total crime resulted in eight fewer number of crimes in the average month. In the Humboldt Park section of Chicago, cameras were associated with a nearly one-third reduction in robberies and drug-related crimes. In contrast, a study of cameras in West Garfield Park, Chicago, “yielded little to report.” And a camera system in Washington, D.C., “did not appear to have an impact on crime.”

 Time series graph of crime count in downtown Baltimore from 2003 to 2008 showing the reduction in crime after the installation of security cameras in 2005.
The installation of 50 on-street cameras resulted in a significant drop in crime in downtown Baltimore.
p. 31, 7

Start making sense?

Photo of a uniformed man sitting behind a semi-circular desk of several monitors; a wall of large monitors with security footage is visible in the background.
Few eyes, many screens. British highway patrolmen survey countless monitors fed by security footage across Britain’s roadways.

Ubiquitous video cameras have changed policing as they have changed other realms of modern life. While recent events have placed the focus on preventing abuse of authority, the original motivation was to prevent crime or aid the prosecution.

For fixed cameras, used for remote monitoring of streets, parking lots and buildings, both the density of cameras and the intensity of monitoring matter. The location of monitoring sites and the identity of monitors may be regulated to allay privacy concerns, but excess restrictions can obviate benefits. In the ineffective Washington system, for example, all camera feeds went to a central office, where video feeds could only be monitored when a police lieutenant was present. Police departments have much wider access in other systems, which may increase the chance of noticing aberrant behavior.

Monitoring can be boring, and when the person watching the monitors is inattentive or sleepy, the result may be a false sense of security.

Policy decisions also matter in the acquisition and use of video evidence:

when car- and body-cams must be running

penalties for turning cameras off

where and how long video files must be retained

Finally, consider the “CSI effect.” Prosecutors worry that once cameras become widespread, judges and juries will begin to expect a video record of crimes, and will subconsciously downgrade other forms of evidence in favor of whatever can be verified via video.

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. The effect of police body-worn cameras on use-of-force and citizens’ complaints against the police: A randomized, controlled trial, Barak Ariel et al, Journal of Quantitative Criminology, 2014.
  2. White, Michael D., Aug. 2014. Police Officer Body-Worn Cameras: Assessing the Evidence. Washington, DC; “Office of Community Oriented Policing Services
  3. The effect of police body-worn cameras on use-of-force and citizens’ complaints against the police: A randomized, controlled trial, Barak Ariel et al, Journal of Quantitative Criminology, 2014.
  4. A National Study on the Use and Impact of In-Car Cameras, International Association of Chiefs of Police, In-Car Camera Project, 2001.
  5. Public Area CCTV and Crime Prevention: An Updated Systematic Review and Meta-Analysis, Brandon C. Welsh and David P. Farrington, Justice Quarterly, Vol. 26 #4 (December 2009)
  6. Evaluating the Use of Public Surveillance Cameras for Crime Control and Prevention, Nancy G. La Vigne et al, Urban Institute, Sept. 2011
  7. Evaluating the Use of Public Surveillance Cameras for Crime Control and Prevention, Nancy G. La Vigne et al, Urban Institute, Sept. 2011.
  8. Viewer discretion advised: Body-cam footage of Idaho police officer shooting man with knife…
  9. Suicide by cop in Ohio
  10. UK and US watchdogs warn of surveillance risks and the impact on society.
  11. Los Angeles police order Tasers that activate body cameras.
  12. The NYPD officers who see racial bias in the NYPD.
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Reel to Real: Science caught on tape Fri, 26 Dec 2014 05:45:03 +0000 More »]]>
Reel to Real: Science caught on tape

1. Poetry in motion

Aerial combat: Hawk 1, drone 0

Aluminum, four rotors and one tiny radio meet an ancient definition of territoriality — and talons and beak show who’s boss.

69 years: Patience pays at last!

Call me tar, asphalt or bitumen. I’m 2 million times as viscose as honey, but don’t call me “solid.” No siree! Watch one of the world’s oldest experiments bear [tarry] fruit!

Swarming starlings

Aerial ballet with a cast of thousands: See why everybody is murmuring about “murmuration,” and why you should be, too! One question: Who’s the master of this dance?

Want to take a dip?

First check out the black seadevil, filmed with its flashlight glowing and its needle-like teeth ready for fish paté. Caution: This ambush predator is best appreciated at a distance.

2. Earthly delights

Frozen, now fractured: Gigantic glacier gouged!

Watch a giant Greenland glacier join the ocean. Enjoy (is that the right word?) the slow-motion train wreck that is our in a portrait of the Anthropocene — the era of human domination.

Domes for one, domes for all

Giant gobs of granite form when magma cools below ground. As these “plutons” rise, pressure drops, and sheets of rock break off an “onion-like structure. “Exfoliation” shapes a vaguely spherical structure — like Half Dome at Yosemite.

Clouds do the wave

Plains-staters know whacky weather, including a weirdo cloud that’s taking Middle America by storm. Meet undulatus asparatus, the first cloud type up for induction in the International Cloud Atlas in 60+ years. Watch asparatus roll through the sky as buoyancy and gravity duke it out in the clouds!

3. Drinks and dining

Cat claims croc

It’s all in the technique as a jaguar stalks and captures a caiman — a relative of the crocodile.

Tubular trouble: Monster leech sucks down worm!

Tell us the truth: Is this the first time in your life that you ever felt sorry for a worm?

Primates pouring at publick house!

First vervet monkeys learned to eat fermented sugar cane. Then all hell broke lose. These drunken monkeys prove that even addiction studies don’t have to be all serious, all the time.

You got a license, pal? Gladiator spider traps with a net

Grab a ringside seat, fire up the fuzzy filament, and watch this lethal lady make her net — and use it. It’s easy to love — unless you are a cricket…

– David J. Tenenbaum

Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer

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Europe: Return of the carnivores! Thu, 18 Dec 2014 19:33:24 +0000 More »]]>
Europe: Return of the carnivores!
A Eurasian lynx with a thick fur coat perches on a mossy, downed tree trunk, gazing toward a distant object, looking ready to strike.
The Eurasian lynx is Europe’s largest cat. The new study finds them abundant in Finland, Sweden and Norway, the Baltics, Balkans and Romania.
Copyright: Miha Krofel, Slovenia

A surprising new study shows that four big carnivores (brown bear, lynx, wolverine and wolf) are doing quite nicely in Europe, thank you very much, even without the wilderness protection that benefits some large predators in the United States.

“We find that in Europe we have twice as many wolves as in the lower 48 (American) states, on half the land area, with two times the human population density,” says Guillaume Chapron of the Swedish University of Agricultural Sciences, the corresponding author of the new study.

In Europe, as in North America, large carnivores face ingrained hostility. It’s not just their ferocity, but also their need for a large range and lots of meat that makes them natural competitors.

Photo of two fuzzy wolf pups standing in the sun in a grassy opening
Wolf pups photographed in front of their den in western Poland.
Credit: Robert W. Myslajek

Add it up, and both Europe and the United States had severe losses of carnivore populations by the 1960s.

Wilderness reserves and national parks in North America are intended to separate animals from people, but the new study points to other ways to ensure predator survival. “If we had followed the North American model of wilderness in Europe, we would not have predators, because in Europe everything is developed, we have roads everywhere,” Chapron says.

The study, “shows that this coexistence, this ‘land sharing,’ does not just work in a particular context, it is working on a continental scale,” says Chapron. “It’s possible to have predators living in a human-dominated landscape, and this is unexpected.”

Predator stomping grounds
Four maps showing the spread of large carnivores across Europe, with images of a bear, wolf, lynx and wolverine. Bears, lynx and wolverines appear concentrated in Fennoscandinavia, and wolves reside primarily across the Balkan countries and eastern Europe.
Location of bear, wolf, lynx and wolverine populations across Europe between 2010 and 2012; permanent populations shown in dark orange, and occasional sightings shown in light orange.

The 1970s: A turnaround

Photo of a wolverine standing on an overturned tree near a pond with lily pads.
Wolverines are adapted to living in the snow. This one is near a pond in Finland.

The same environmental awareness that sparked the Endangered Species Act (ESA) in the United States in the 1970s also affected Europe, Chapron says. “In Europe … we have our own ESA and habitat directives that protect wildlife and wildlife habitat.” Member states of the European Union are obligated to restore wildlife populations and habitat, he says. “The willingness of society to have a good relationship with wildlife has been a key reason why this has turned into a success story.”

Photo of three wolves greeting one another in a forest opening. Wolves do eat livestock, and in Europe (much as in the United States), problem wolves can be shot even though they are protected.
Highly intelligent and cooperative, the wolf pack forms a hunting machine with a large territory.
Copyright: Miha Krofel, Slovenia

Of the four predators, the oft-feared wolf has staged the most dramatic recovery, Chapron says. Since the 1950s and ’60s, wolves have become more numerous in Finland and Poland, and breeding populations have returned to Sweden, France, Germany and Norway. “The wolf was never deliberately reintroduced in Europe,” Chapron says. “The wolf has done all of this naturally.”

The territory of European wolves has, on average, 37 people per square kilometer. (That’s 103 per square mile, or about the same density as the state of Alabama.) “That clearly shows the wolf can live in places with people; they don’t need a totally empty landscape,” Chapron says.

Although the findings are encouraging for those who see predators as necessary to a healthy ecosystem, “This coexistence is not a peaceful love story,” says Chapron. “With carnivores, there will always be conflicts. They are big, they eat the wrong type of meat, including meat we would like to eat. The goal is not to have no conflict at all, because I don’t think that’s possible.”

– David J. Tenenbaum

1 2 3 4

Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. Recovery of large carnivores in Europe’s modern human-dominated landscapes, Guillaume Chapron et al, Science, 19 December 2014.
  2. Europe’s large carnivore initiative webpage.
  3. The status of large carnivores in Europe, 2013.
  4. Why should we care about carnivores in North America?
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Happy holidays: Inventions we need now! Thu, 11 Dec 2014 20:11:21 +0000 More »]]>
Happy holidays: Inventions we need now!

Can’t decide if you want a scarf or a fruitcake? Aim higher! The Why Files cooked up a science-lab wish list for the season. Let’s meet ‘n greet The Why Files big four inventions for a happier, healthier tomorrow!

Pie in sky? Why not stash carbon dioxide in the basement?

Three-dimensional diagram of rock layers underlying CO2 injection wells, where liquefied carbon is pumped below "cap" rocks into oil, coal and gas reserves, as well as unusable aquifers.
Adopting a method used to increase flow of oil to the surface, carbon capture and storage places liquefied carbon dioxide from coal plants deep beneath Earth’s surface, in porous rock formations under dense “cap” rocks that should permanently hold the carbon. But how much testing is needed to assure permanence?

The problem: Carbon dioxide – the king of the greenhouse gases – is warming the climate and raising sea level.

The holiday gift: A technology called “carbon capture and storage” (CCS) has panacea scrawled all over it: Solve the problem of fossil-fuel carbon dioxide by capturing the gas at the generating station. Inject it deep into the ground, where it will — we hope — solidify into stone.

Because carbon dioxide injections mobilize oil in partly-spent oil fields, this pollutant is worth money. Oil recovery is the goal of 20 of 27 CCS projects now operating or being built. The other seven will inject the gas into deep rock formations beneath a cap rock.

CCs is difficult, and expensive: the budget for the flagship U.S. effort, the Kemper-IGCC project in Mississippi, has ballooned from $2.4 billion to $5.6 billion. The plant is scheduled to start in May, 2015, one year late, and to pipe its carbon dioxide to an oil field.

A steel plant in the United Arab Emirates is expected to start injecting 800,000 tons of carbon dioxide for oil recovery in 2015.

The upshot: CCS is unproven, and even a rapid move toward a safe, affordable technology will not come close to solving our climate woes. More research is needed. If the goal is to store carbon underground, it may even be cheaper to leave petroleum, natural gas and coal where it is.

Universal flu vaccine

The problem: Influenza keeps evolving, so we need a new flu shot every year, and it doesn’t always work.

Black and white photograph of nurses donned with surgical masks hefting an infected flu victim on a stretcher into a Red Cross ambulance.
The Motor Corps of the St. Louis chapter of the American Red Cross on ambulance duty during the influenza epidemic. In 1918 and 1919, in the aftermath of World War I, influenza killed 50 to 100 million around the world.
Photo: October 1918 Influenza archive

The holiday gift: Influenza viruses evolve to battle the immune system. Immunity to last year’s virus fails against this year viruses, so we need an annual vaccination containing viruses expected in the coming flu season, and predictions are chancy. So flu researchers dream of a universal vaccine that would protect against any virus strain, even a deadly flu like H5N1. Now, some of the obstacles have become clear — and perhaps surmountable, says Thomas Friedrich, a virologist and associate professor in the School of Veterinary Medicine at the University of Wisconsin-Madison. These three improvements would go a long way toward improving protection against flu.

Generate “broadly neutralizing” antibodies. The flu shot induces antibodies, immune molecules that block structures the virus uses to infect cells. Because the antibodies are targeted against strains present in the vaccine, the virus is forced to evolve to “escape” the vaccine. Researchers have recently found people and animals with antibodies that neutralize most flu strains, even bird flu. Still to come: ways to induce these broad antibodies with a vaccine.

Recruit additional “arms” of the immune response: Currently, vaccines induce antibodies that recognize fast-evolving parts of the virus. T cells and non-neutralizing antibodies that recognize static elements could be effective against many strains, if we are able to stimulate them with vaccine.

Make vaccines faster: It takes almost a year to grow vaccine in chicken eggs — after next year’s strains are selected. Vaccine producers are adopting modern cellular and molecular biology techniques that hasten this process, but the pace remains slow.

The upshot: A universal vaccine will not arrive tomorrow, but progress is likely with good funding.

Better antibiotics on the horizon?

False-colored, electron microscope image of the spherical "staph" virus being engulfed by voracious white blood cells.
Scanning electron micrograph of a human neutrophil ingesting MRSA (methicillin-resistant staph aureus), a drug-resistant “superbug.”

The problem: Abuse of antibiotics, in human health and animal agriculture, has caused a resistance crisis. When antibiotics kill susceptible bacteria, the bugs evolve toward resistance.”Super-bugs” are emerging from India, where babies are routinely injected with strong antibiotics, which helps accelerate the very infections they are intended to save.

The holiday gift: Antibiotics that work without killing bacteria. The idea is not to be nice to pathogens, but to avoid causing resistance to evolve.

Quorum sensing: Many bacteria release “I-am-here” chemical that their own species can detect. Once the microbes are numerous enough to withstand immune attack (when they reach their “quorum”), their behavior can change from harmless to hateful, as they secrete toxins or tissue-destroying enzymes, or form a biofilm that protects from harm. At UW-Madison, Helen Blackwell is investigating the signals of quorum sensing in an effort to trick bacteria into thinking that their numbers are small so they remain harmless. She says such a tactic could avoid the antibiotic-resistance paradigm. Because the bacteria are not killed, there is no selective pressure for resistance.

Interrupting the cell cycle: Another way to monkey-wrench the microbial menaces occurs when bacteria multiply and break proteins using enzymes called proteases. “When the environment becomes damaging, these proteases selectively target particular proteins to stop cell division so the bacteria can focus instead on repair until the stress is over,” explains “Peter Chien, of the University of Massachusetts Amherst. “Understanding how bacteria use these machines at the cellular and molecular level could reveal avenues for discovery of new drugs to treat infectious diseases.”

Madison (Wis.) Metropolitan Sewerage District distributes biosolids — the remains left after sewage is processed — to nearby farms. The district injects its liquid fertilizer-soil conditioner into the soil, minimizing runoff and odor. Rollover to see the injection machine being filled: Notice the tidy bucket that catches spills during the transfer?
1992 photos courtesy David Tenenbaum

The upshot: Learning to mess with the bacterial signals could sidestep the evolved-resistance problem. But don’t count bacteria out. They outnumber us, and they will do anything to come out on top.

Recycle and save soil!

The problem: Soil, the basis of civilization, is easily damaged by erosion, over-cropping, and other abuses. Gardeners compost organic scraps, and municipalities compost the “biosolids” left after biological treatment of sewage. About 60 percent (4 million dry tons) of U.S. biosolids was applied to land after treatment in 2004. It’s time to recycle the 40 percent that was buried or burned.

The gift: Biosolids, when used with care, improve soil’s structure, water retention and nutrient content, while reducing erosion and replacing conventional fertilizers.

Biosolids are the leftovers from sewage, and they can carry toxic metals or pharmaceuticals, but when done correctly, biosolids are more thoroughly analyzed than the conventional fertilizer used on farmland. Biosolids are so effective they can even restore tailings piles at abandoned mines — which leach toxic metals as rainfall and sulfates in the rock form sulfuric acid.

The upshot: More recycling would be better, but the mistaken “don’t defecate on our food” movement is strong. Yet caution is needed. Fear-mongering will only be fed by errors and short-cuts that cause soil or water pollution.

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. ‘Superbugs’ Kill India’s Babies and Pose an Overseas Threat
  2. High Cost Hinders Progress of Carbon Capture As Climate-Change Fix
  3. Potential “universal” influenza vaccine tested at FDA.
  4. Biosolids May Help Fight Global Warming.
  5. Superbugs to kill ‘more than cancer‘ by 2050.
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The deadly jolt of the electric eel Fri, 05 Dec 2014 14:38:51 +0000 More »]]>
The deadly jolt of the electric eel
Photo of an electric eel, set on a white background, its smooth body coiled, 2 tiny fins at front, no fins on top;  with a tiny tail fin.
The electric eel (Electrophorus electricus) has three uses for the electric field it generates.
Courtesy Kenneth Catania, Vanderbilt University

Long before the first battery, the electric eel was an ambassador from the unknown world of electricity. So Kenneth Catania, a professor of biology at Vanderbilt University who has just published a study on the hunting behavior of the eel, was a bit surprised that nobody had studied exactly how the eel attacks its prey.

While teaching about eels, he says, “I got fascinated by their behavior. Under high-speed video — no-one had done that as far as I can tell — the prey were completely immobilized about 3 milliseconds after the eel began its electric attack.”

When the eel’s specialized muscle cells created an electric field in the water, “I imagined the prey would twitch,” Catania says, “but it completely froze up, which suggests this was caused by involuntary muscle contraction, which is pretty much how a Taser works.”

With its prey immobilized, the eel mounts “an incredibly fast, explosive strike,” says Catania. And even though the fish muscle cells must devote energy to generating current, “There was no indication in its behavior that suggests they had lost a substantial amount of movement. I thought, and others thought, the electric eel could lazily swim up, shock and consume the prey.”

All things considered, Catania says the eels “are quite a formidable predator.” In its native Amazon Basin, “Fishermen really don’t like them, and there are historic accounts of people who study eels who have slipped, been shocked and immobilized.”

Photograph of an elderly fisherman in a hand-carved canoe floating on the muddy waters of the Amazon.
The electric eel thrives in the shallow, murky waters of the Amazon Basin, where it locates hidden prey with low-energy electric discharges.
Photo: Shutterstock.

A three-step “dance of doom”

But the shocks are only the final step in a sophisticated, three-prong attack. Electrically speaking, the eels use:

A form of low-voltage (think electric sonar) to detect prey in its muddy environment.

A different, low-voltage signal that elicits a twitch from nearby prey that makes waves that the eel’s pressure sensors can detect.

The immobilizing jolt at a frequency of 400 hertz. At 600 volts, it’s more than four times the voltage of household current. The attack causes tetanus — a widespread explosion of muscular activity that turns the fish into a rigid, helpless dinner.

“It’s a very sophisticated animal,” says Catania. “It’s got eyes, and even though a lot of people say they are mostly blind, the ones I study clearly are paying attention visually. They have passive electrical receptors and active electrical receptors; they can probe with electricity, and have that high-voltage immobilizing discharge. And they are incredibly sensitive to slight water movement, which will cause them to attack almost immediately.”

A large electric eel captures a fish during its high-voltage discharge. The clicking sound represents the electric signal in the water; notice how the frequency changes before and after the attack. The slower clicks are used to detect prey, not immobilize it.
Courtesy Kenneth Catania

“First, you become my slave. Then you die!”

Perhaps the most astonishing part of the story is how the eel seizes control of the prey’s nervous system. In part of the experiment, Catania removed the brain and spinal cord from the prey fish, and saw that the electric attack nonetheless caused its muscles to fire by activating nerves linking the spinal cord to the muscles. “There is a remarkably tight correspondence between eel’s output and the muscles,” Catania says.

Photo of brilliant blue wasp yanking a cockroach’s antennae, leading the insect to the wasp’s lair.
It’s a cruel world: The emerald cockroach wasp converts its prey into zombies — for the benefit of the wasp’s larvae.

Other predators enslave their prey. For example, the emerald cockroach wasp injects its eggs and disables the cockroach’s nervous system, forcing the roach, zombie-like, to carry the wasp’s larvae until the larvae eats it alive. The rabies virus turns dogs aggressive to help the virus spread before its host dies. “But nothing I know of works as fast” as the electric eel, says Catania.

Photo of an electric eel’s head bent upward to face a small, silver fish moments before the prey is swallowed
This electric eel is attacking a fish that been immobilized by the eel’s high-voltage output.
Courtesy Kenneth Catania

If it’s so powerful, why doesn’t the electric eel shock itself? “I’ve not found any obvious explanation,” says Catania. “Presumably there is some way of projecting the electricity through a path of least resistance that does not include its own brain.”

Creating all that electric energy does tire the fish, Catania adds. “You can see, over time, that the frequency of the pulses does slow down.”

All-electric alliance

The electric eel Electrophorus electricus is one of hundreds of fish that create electric current for defense, predation, navigation and communication. A new study by University of Wisconsin-Madison researchers shows that all six electric fish lineages use essentially the same genes and cellular pathways to make the electric organ. “What is amazing is that the electric organ arose independently six times in the course of evolutionary history,” says Lindsay Traeger, a UW-Madison graduate student and a co-lead author of the report.

Some scientific advances rely on new instrumentation or theories, but not the current (heh-heh!) study. Instead, the hunting behavior of the electric eel was hiding in plain sight. “Maybe it sounded open and shut,” Catania says, when asked why the eel’s electric secret was not unraveled before now. “What was there to know if eel shocked the heck out of its prey? But it turned out to be far more interesting than you could have imagined.”

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. The shocking predatory strike of the electric eel, Kenneth Catania, Science, 5 December, 2014.
  2. Sequencing electric eel genome unlocks shocking secrets.
  3. Eel muscle could be the first step towards human-generated electricity.
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Eating to extinction (Happy Thanksgiving, bird eaters!) Thu, 27 Nov 2014 13:33:27 +0000 More »]]>
Eating to extinction (Happy Thanksgiving, bird eaters!)
A prone man  aims shotgun, resting on log, at 3 turkeys; an Indian guide crouches behind him.
1890 lithograph by Rufus Fairchild Zogbaum, Harry T. Peters “America on Stone” Lithography Collection

Sept. 1, 1914: The passenger pigeon goes extinct after billions were shot to feed hungry urban markets during the preceding century.

Nov. 27, 2014: Thanksgiving, the day we gobble gobblers (AKA turkeys) and wonder: Is the original Thanksgiving meat now extinct? Hint: It’s not the wild turkey.

The turkey, supposedly the focus of the Pilgrim’s first feasts, was eliminated across much of its wild realm by over-hunting and habitat destruction. These days, after extensive restoration efforts, the wild turkey is easy to find (though reputedly difficult to hunt).

But we’ve learned that the heath hen, a smaller bird that was more common in the Northeast during Pilgrim times, was more likely the focus of the feeding frenzy in those first feasts. If so, the true “Thanksgiving turkey” went extinct in 1932.

Thanksgiving ruminations: Remembering the birds we ate ’til they were gone!

ird with striped feathers seen in profile,  with crest on its head.

Heath Hen

Ornithologist and conservationist Stanley Temple at the University of Wisconsin-Madison, says “Many people, myself included, believe the Pilgrim Thanksgiving meal was not turkey but the heath hen.” The area had few turkeys, but the many heath hens “were intensely hunted and very good to eat. I don’t think anyone would argue against overkill, over-hunting as the major cause of their demise.” By the late 19th century, heath hens were only found on Martha’s Vineyard, an island only 50 miles from the Pilgrim’s colony at Plymouth, Mass. Even though a large preserve was created for them, heath hens were battered by predatory birds, a catastrophic fire during nesting season and possibly diseases carried by poultry. Eventually, low fertility and other symptoms of inbreeding depression appeared, and the birds died out in 1932.
Feathered game of the Northeast, by Walter H. Rich
Mid-1800s wood block engraving of 9 hunters shooting an enormous swarm of passenger pigeons; some birds fall, and hunters collect them from the ground.

Passenger Pigeon

In 1871, hundreds of millions of passenger pigeons nested across 850 square miles of central Wisconsin, and eyewitnesses reported that almost every tree held dozens of nests. So if any bird seemed extinction-proof, it was this one, but later in the century, squads of “pigeoners” travelling the new railroads shotgunned these colonial-nesting birds and stuffed their carcasses into barrels for shipment to Eastern and Midwestern cities. “Martha,” the last of her species, died in a Cincinnati zoo in 1914.
A plump dodo, with huge bill, in profile, before other extinct birds


The dodo, a pigeon-family bird that lived and died on the island of Mauritius in the Indian Ocean, has come to symbolize both death (“dead as a dodo”) and extinction. The island lacked mammals, so the bird was unfamiliar with their rapacious ways, making it easy prey for hungry sailors who arrived in 1598. The dodo was gone by 1662, or perhaps a few years later. With such a quick extinction, it’s impossible to know precisely the bird’s appearance or behavior, but it was about one meter tall and apparently not fearful enough for its own good. A wide range of other animals on Mauritius went extinct, including the Mauritian duck and the Round Island burrowing boa. And although the dodo came to exemplify the idea that people could eat birds to extinction, introduced monkeys, rats and cats may have played a bigger role, says Temple.
“Edward’s Dodo,” painted by Roelant Savery, in 1626 Public Domain
Photo: Short, squat pigeon with wings flexed; tail feathers are bright pink, breast pinkish-white, bird has band on leg.

Pink Pigeon

A relative of the dodo shows how a bird can resist extermination through clever chemistry. The pink pigeon ate tropical fruits loaded with toxic alkaloids and was the only pigeon species on Mauritius not hunted to extinction. “Once the report got out that you would became deathly ill if you ate the pink pigeon, it survived,” says Temple, a professor emeritus of wildlife ecology. As a young ornithologist on Mauritius, Temple had a taste of the pigeon’s menacing meals. “Whenever I saw a bird feeding on something, I would pluck a piece of fruit and touch it to my tongue,” he says. “I saw a pigeon eat several fruits and picked one on the tip of my tongue, and most of my throat and mouth went numb, like I’d been shot with Novocain.” Although the pink pigeon survived, and hundreds live in captivity, it is endangered by habitat loss.
Illustration of long-legged, long-beaked birds on a rock and grass; one bird lies on its back, presumably dead

Eskimo curlew

The Eskimo curlew almost certainly met its demise via a hungry market. Possibly the most numerous migratory bird in North America, their numbers plummeted in the late 1800s after market hunters targeted them as the supply of passenger pigeons petered out. Large flocks of curlews migrated south along the Eastern Seaboard to the Caribbean and South America, then back north through Texas and the Great Plains, where, according to some accounts, millions were slaughtered annually. Although the species hasn’t been seen, officially, since the 1960s, occasional sightings are claimed.
Painting by John James Audubon
Illustration of three waterfowl -- a black and white male, brown female and juvenile -- wading in chilly waters and perched on floating ice.

Labrador duck

Cold winters in New York spelled trouble for the hapless Labrador duck, which wintered along the New England coast and Long Island Sound. Wintering waterfowl were a big source of meat supplied to New York City markets. Although the Labrador duck wasn’t the tastiest tidbit on the menu, its conspicuous plumage made it an easy target. The last one was seen on Long Island Sound in 1875.
Illustrated by J.G. Keulemans, Rowley’s Ornithological Miscellany Vol II
Drawing of two large ostrich-like birds in a tropical landscape, unaware of the looming Maori hunter brandishing a spear from behind a tree. 

Giant moa

When Polynesian settlers called the Maori landed on the islands of New Zealand around 1280, they encountered several endemic species of moas: large, wingless cousins of the ostrich. Confined to islands, and never knowing humans, the moas were easy prey for the Maori. Even the topographically and ecologically diverse landscape of New Zealand couldn’t curb the hunters’ excess success. Radiocarbon dating shows all species of moa were hunted to extinction within 200 years of Maori arrival. Not a single species in the moa genus survived the 15th century, not even these 12-foot-tall giants.
From Extinct Monsters: A popular account of some of the larger forms of ancient animal life, by Rev. H. N. Hutchinson, 1896.

Add it up, and you have to start wondering about the birds we love to eat. How much “love” is too much love? Lest you argue that we have learned from our history, Temple points to the bluefin tuna — a heavily fished delicacy of the sea that is, he suspects, headed for extinction. “You could superimpose the trajectory of the passenger pigeon’s decline on this modern day example, which we are exploiting with deadly efficiency,” he says. “It reminds me of the passenger pigeon, where the simple answer is that we killed ‘em and ate ‘em.”

– David J. Tenenbaum & Kevin D. Barrett

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. Dodo, a lá Wiki.
  2. Pacific island birds: 1,000 species gone!
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Bankers: dishonest when banking is on their minds? Thu, 20 Nov 2014 15:28:34 +0000 More »]]>
Bankers: dishonest when banking is on their minds!

Be honest: Do you look at banking and other financial institutions and imagine the swishing sound of billions of dollars and euros flushing down the drain? Lies, thefts and frauds are not getting any scarcer grow among the people who handle money, so we ask:

Flyer on a metal pole carries image of a smirking Bob Diamond, reading, 'I've got your money, and I'm keeping it! Why isn't Bob Diamond in prison?'
When a bank pays interest on your savings account, or charges interest on a loan, who sets the interest rate? The bank, usually based on Libor (London interbank offered rate). So tempers flared when major London-based bank Barclay’s was caught rigging Libor. Former Barclay’s CEO Bob Diamond resigned in 2012, and the company handed over a $435 million settlement to U.S. and British authorities. On Nov. 19, 2014, National Public Radio reported that the Federal Reserve is talking with European authorities about finding a replacement for Libor. The same day, we learned that “ANZ, one of Australia’s biggest banks, has suspended seven traders as part of an inquiry into the potential rigging of key interbank interest rates.”
Photo: duncan c

Who takes? What gives?

The august scientific journal Nature took a stab at explaining the apparent rise in financial cheating with a study by three researchers at the University of Zurich (a banking capital!) who looked at 120 employees of an anonymous international bank. The study rested on the concept of “salience,” the idea that behavior is affected by thoughts and values that happen to be present in our minds.

The question was, are bankers less honest when the thoughts and values associated with banking are running through their minds?

Who takes?

The study was built around a coin-flip experiment. Participants were told which side would win, and asked to report the result after each of 10 flips. Wins were worth $20 apiece. Statistics were the only way for the testers to know if the subject was being honest — in the long run, close to 50 percent of the flips should be heads, so any deviation from 50-50 marked dishonesty.

In the control situation, the bankers were asked a series of generic questions about their lives; in the experimental situation, some of the question were intended to raise the salience of banking, such as, “What is your function at the bank?”

 Man-on-the-street -shot of a worried man in a navy suit amid press cameras and reporters.
Wall Street billionaire Raj Rajaratnam was convicted on five counts of conspiracy and nine counts of securities fraud in 2011, and is serving an 11 year sentence. According to Preet Bharara, the federal prosecutor who put him away, “Rajaratnam was among the best and the brightest — one of the most educated, successful and privileged professionals in the country. Yet, like so many others recently, he let greed and corruption cause his undoing.”
Photo: GalleryHip

Bankers responded honestly, essentially stating that half the throws were winners — unless the thoughts of banking were raised. But after the banking prompts, 58.2 percent of their responses were winners — a result that is not possible given the random results of flipping a coin many times. Close to 10 percent of the primed bankers reported a win on every throw, a result that would be expected in about 1 percent of the 120 cases!

What gives?

Why are bankers honest — but only until they are reminded that they work in a bank? The cause seems to lie in the bank culture or values, says author Ernst Fehr, a professor of economics, who commented in a conference call that the spate of banking and financial scandals “raise question of whether the business culture in banks is favoring, or tolerating, fraud, to a larger degree than business culture in other industries.”

The researchers wrote that after being reminded of their profession, subjects were significantly more likely to “endorse the statement that social status is primarily determined by financial success.” That endorsement, they added, “is positively correlated with the reported number of successful outcomes.” Recall that an excessive number of successes involved what we call cheating.

The authors continued that their findings “substantiate current concerns about the influence of materialistic values in the banking sector,” especially since the simple recognition that one is a banker, “may have increased dishonesty through an increase in materialistic values.”

It’s not that bank management is telling employees to be dishonest, “it’s the opposite,” Fehr said. But does not seem to be getting through, he added. “I believe that … what is thought to be implicitly okay is what is showing up here.”

Photo of a smiling white-collar hand-cuffed man escorted from a building by London police officers.
Convicted of fraudulent trading in 2011, Kweku Adoboli’s work at Swiss megabank UBS’s London office cost the company $2.3 billion in losses, called at the time “UK’s biggest fraud.” Billions aside, the conviction also unveiled an atmosphere of negligence and profit-hounding at UBS, leading to the resignation of the bank’s CEO, Oswald Gruebel, and an investigation by the Financial Services Authority. Adoboli has appealed his conviction.

When money talks, can we answer?

Co-author Michel Maréchal, an assistant professor of economics at Zurich, added that “those in the experimental group who most strongly endorse the materialist statement have a positive relationship with dishonesty.” Occupational norms in the banking industry, he added, “put a greater employee emphasis on dishonesty and materialism.”

What can be done, given that financial businesses commonly encourage employees with financial incentives, which the authors said could play a role in the outbreak of cheating.

Recall that the study found that, until being primed to think about banking, these bank employees “are basically honest, so it’s really the cultural aspect, the unwritten norms and values that prevail in the company that seem to make them more dishonest, and that is something we can change,” said Fehr.

Incentives may offer one basis for fighting dishonesty, Fehr said, since any incentive “can be an incentive for being dishonest… and the stronger it is, the bigger is the problem. We don’t argue for removing all incentives, but maybe we should reduce the strength of these incentives.”

A second fix may reside in trying to counter the professional norms with pledges or standards, a tactic that is being tested to battle fraud among taxpayers and insurance claimants.

– David J. Tenenbaum

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Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer


  1. Business culture and dishonesty in the banking industry, Alain Cohn, Ernst Fehr & Michel André Maréchal, Nature (online 19 November, 2014).
  2. What science tells us about why we lie.
  3. Convicted of felonies, banks are allowed to stay in business.
  4. What’s so significant about Barclays Bank lying about the interest rate they paid on loans?
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