Book Review : The Bleeding Disease: Hemophilia and the Unintended Consequences of Medical Progress by Stephen Pemberton

A historian shows how advances in treatment made hemophilia manageable — yet led to many deaths from HIV-tainted plasma.

Johns Hopkins Univ. Press, 2011, 377 p., $50

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When birds go to town

Paris crows feast on some human leftovers. They’re not the only birds that have learned to like garbage.WITT/SIPA/Associated Press

Anne Clark and Kevin McGowan are discussing, perfectly seriously, how a crow might be able to recognize a car. Not tell a car from, say, a cat, but pick out the red Subaru from other cars in the parking lot.

Clark, an animal behaviorist at Binghamton University in New York, is sitting in her own red Subaru with McGowan, of Cornell’s Laboratory of Ornithology in Ithaca. Neither bothers to mention — it’s apparently so routine — that when Clark pulled into the lot, two crows flapped over to nearby trees. Country crows often back away from human doings, but these birds lingered as if people-watching.

Clark and McGowan are running a long-term study of what urban life is like for a group of Ithaca’s crows, tagging and following them as they grow up, take over or lose territories, and succeed or not in raising the next generation of research subjects. Even in a university town, the birds probably aren’t lured to the Subaru by the thrill of scientific discovery, but rather by the scientists’ occasional ploy of flinging peanuts and dog food out the window to engineer some bird activity.

“They know us,” McGowan says. There isn’t another Subaru in the lot to test the birds’ discriminatory abilities, but McGowan has inadvertently conducted his own experiment. He sold his car and bought a new one. McGowan was temporarily invisible automotively, but the birds caught on eventually. And the old car’s new owner reported that a crow appeared to be following him to work. It was OK; the driver just provisioned the car with peanuts for an occasional fling.

New food sources are just one of the opportunities that organisms of all kinds — including ants, birds and cockroaches on down to zoysia grass — encounter when they take up life around people. As human populations boom, more and more plants and animals are becoming city dwellers, a shift that intrigues biologists fretting over the practical problems of nuisance critters as well as theoreticians musing over how organisms adapt to new environments. For even a green town presents plenty of novelty unknown in any species’ evolutionary history.

Dropping dietary clues View larger image | Glaucous gulls living around the town of Deadhorse, Alaska, get much of their food in the form of human garbage, researchers recently found. This part of the diet proved particularly important to the gulls during chick rearing. Rural birds studied in Simpson, Alaska, appeared to get their dinner elsewhere.E.l. Weiser and A.N. Powell/Condor 2010

The considerable number of birds that now share cities and suburbs offer as good a focus as any for scientists trying to understand what happens when animals go to town. Though some birds are seizing new opportunities, the lifestyle often comes with costs. Biologists are now beginning to see how birds respond to some of the major facts of city life, from discarded french fries to relentless low-pitched noise.

And other studies are showing how, by encouraging species that can cope and filtering out those that can’t, urban areas are creating mix-and-match combos of inhabitants that have never had to deal with each other in quite the same way before. Odd juxtapositions of predators, competitors, prey and, oh my, people become a challenge in themselves.

Feed me

Clark and McGowan didn’t intentionally train Ithaca’s crow population to car watch, and the researchers throw food only when other attempts to coax a bird to cooperate have failed. Still, Team Crow’s adventures in the parking lot turn out to be a classic example of the new crow-human dealings that emerge where people abound. One of the big attractions of these urban environments is all the leftover and left-outside human food just waiting for the enterprising forager.

Clark, McGowan and Binghamton graduate student Jennifer Campbell-Smith are searching for this year’s nests so McGowan or another tree climber can band nestlings. The nestlings will be included in a database of crow families going back more than two decades. Crow family territories in Ithaca are smaller and nestle together much more densely than they do in rural New York, and the family sagas are complex. A day riding around on a spring nest survey is like dropping in from Mars and having to pick up the plotlines of The Sopranos, Lost and a lot of Shakespeare, all with feathers.

Urban birds deal with new surroundings in innovative ways. This hummingbird nest is in a power plant’s boiler feed return pipe.Jon Ridler, Cornell Lab of Ornithology, www.CelebrateUrbanBirds.org

All morning Clark has proved almost clairvoyant at driving in traffic along Ithaca roads and suddenly veering onto the shoulder after glimpsing the dark form of a nest among the many dark forms in conifers half a block away. The woods by the parking lot are tough even for the clairvoyant, though. A crow pair nested here last year, but the team never determined which tree held the young.

Crows are nesting in the same clump of trees this year, and the dilemma calls for flinging food in hopes that the birds it draws will take some back to the nest. They readily flap down to the asphalt to pick up the goodies and fly off with bulging beakfuls. A few loads get ferried into the dense tangle of branches in an uphill corner of the pines, but again, spotting which tree has the nest proves tricky.

There’s another handful of peanuts. And another. After more than an hour of observation from the parking lot, the woods and two vantage points in a cemetery across the street, there’s still no obvious tree. The crows have gotten a fine lunch but have managed to keep their nesting address private. One might ask who trained whom.

For birds such as these Ithaca crows, which can balance a natural wariness with some strategic boldness, the world is their garbage dump. A 2010 study of glaucous gulls found that birds in northern Alaska towns rely heavily on human garbage, with up to 85 percent of regurgitated pellets and breeding-season bird remains including human leftovers. In Seattle it’s “roadkills, Cheetos and french fries, and Kentucky Fried Chicken — all the favorites,” says John Marzluff of the University of Washington.

In an upcoming article in Studies in Avian Biology, Marzluff discusses classic studies of three bird populations that picked up the knack of opening, and drinking from, milk bottles delivered to people’s doorsteps in the morning. He says Seattle’s crows even know what time the keepers at the zoo throw fish to the penguins, and the birds show up to vie for the handouts.

OVER THE GRUMBLEThe sounds of the city can drown out the lower ranges of a bird’s songs (figures show a great tit song in a quiet forest and the same song masked by urban rumblings). Recent studies suggest birds try to accommodate in various ways.H. Slabbekoorn

On the other side of the Pacific, birds known as jungle crows have visited a shrine in Kyoto and helped themselves to some of the thousands of fat-rich, potentially crow-edible candles set out along the paths. Video recordings revealed that the crows don’t shrink from flames, says Hiroyoshi Higuchi of the University of Tokyo. Crows carried still-smoldering candles away, suggesting an explanation for puzzling fires in fields nearby.

Human food, even when it’s not aflame, may not be so good for birds, though. In a 2009 study comparing the effects of available food on chick rearing in suburban and rural places, Clark, McGowan and Rebecca Heiss, a graduate student at Binghamton at the time, reported evidence that nutrient deficits in suburbia may be limiting the growth of young crows there. Suburban crows lag behind country cousins in size, and offering suburbanites high-protein, high-calcium supplements boosted nestling growth. What startled the researchers, though, was what happened when they set out supplemental nestling food in the countryside. Crows that took home the best nutritional formula used by specialists in nursing orphan chicks ended up with noticeably punier youngsters than neighbors relying entirely on wild food. Even the best food that humans could concoct fell short of a natural diet.

What human nutrition does for birds seems to depend on the species, meaning some dive and others thrive. Abundant human garbage, for example, is proposed as one of the drivers behind population booms in urban gulls worldwide over the last 50 years. The garbage in the diets of those glaucous gulls in northern Alaska turned out to be important in successfully raising chicks, according to an analysis in the fall 2010 issue of the Condor.

Yet the glaucous gulls also hunt other birds. Work done at the University of Alaska Fairbanks by Emily Weiser and Abby Powell has confirmed that remains of more than a dozen at-risk bird species turned up along with the garbage in gull nest debris. While garbage may be a boon for the gulls, their rising numbers may lead to more predation on rare birds — changing the circumstances for these already stressed populations.

Even the abundant food that human enthusiasts set out on their feeders comes with complications, writes Darryl Jones of Griffith University in Nathan, Australia, in the spring 2011 issue of Emu. Evidence so far suggests that feeding birds during the winter increases their chance of survival and advances the timing of nesting and egg laying come spring, meaning more time for raising young. Yet feeding can also push birds out of sync with natural food supplies and may encourage migratory species to stick around all year, possibly competing with winter residents.

BEWARE THE CAVEMANBirds seem to be capable of recognizing threatening people, and can pass that concern on to others. The map below shows sites in Seattle where researchers in caveman masks captured crows and locations where the same masks elicited scolding from birds more than two years later.H.N. Cornell et al/Proceedings of the Royal Society B 2011, adapted by T. Dubé

“There is absolutely no doubt that this amount of human provisioning is having massive and widespread influences on bird populations,” Jones says, “and we really need to know what is happening.”

Sounds of the city

Fine urban dining options often come with unnatural noise. But oddly enough, studies in the 1990s didn’t find that rumbling traffic affected the way city birds sing, says Hans Slabbekoorn of Leiden University in the Netherlands.

Unaware of those negative results at the time, Slabbekoorn went about carefully checking noise in male great tit territories. The more traffic noise competing with a male’s arias, the higher their minimum frequency, Slabbekoorn’s team reported in 2003. Much of the cacophony of urban environments, the cars and air conditioners and leaf blowers and such, growl and grind in the lower frequencies. Studies now suggest that birds can show some musical accommodation.

The frequency change that human hubbub prompts in great tits doesn’t come from singing the same songs at a different pitch, Slabbekoorn and graduate student Wouter Halfwerk announced in 2009. In a study designed to get at the mechanism of the song accommodation, the team experimented with individual birds, analyzing their normal songs and then playing some recorded urban rumble-grumble. Great tits have individual repertoires of up to nine songs. “Peta peta peta,” Slabbekoorn sings, a song heard from the same bird that also does “petati petati.” Lower pitches, prone to get drowned out, dominate some of these songs but not others. During the sessions of recorded urban noise, males sang fewer of the songs with substantial lower notes, showing off more of the high end of the repertoire.

As an additional test, the researchers played what they call reverse urban noise, an artificially created opposite to traffic sounds that puts most of the sound energy at the higher frequencies instead of the lower ones. Confronted with this vexation, the males abandoned the higher-pitched tunes in their repertoire and returned to the lower ones.

Song switching may be the great tit way, but researchers are finding it’s not the only way birds get around extra sound. Nightingales tend to sing louder in loud places, and European robins grow more likely to sing at the formerly unrobinlike hours of the relatively quiet urban night.

While birdsong may be music to human ears, to the birds themselves it’s, “Get your foul feathered rump out of my territory right now,” “Choose me, baby” or some other vital communication. Disrupting such important messages or sabotaging some other aspect of sound could be exacting costs even for birds that readily live in the din. It’s a tricky matter to test, but Slabbekoorn’s group has some evidence. Great tits nesting at various distances from a Dutch motorway fledged fewer offspring in noisier territories, his team reported in the February Journal of Applied Ecology. Though tits persist, they’re paying a price for their urban homes.

And, like any other bit of city living, noise can affect different dwellers differently. Investigating that variability has been challenging because shrubbery, food, pollution, people and plenty of other factors vary along with city noise. For a cleaner test, one team turned to another kind of noisy environment: land around natural gas wells. In piñon-juniper forests of the southwestern United States, some wells run thundering compressors around the clock while others in the same kind of woodlands don’t. Loud compressor zones had about the same number of bird nests as quiet sites, but only 21 nesting species instead of 32, says Clinton Francis of the National Evolutionary Synthesis Center in Durham, N.C.

One of the species conspicuously rare around compressors was the Western scrub jay, which raids nests of a variety of species and eats the eggs. Low risk of jays may have had something to do with why several species such as black-chinned hummingbirds appeared to favor noisy sites. And low numbers of jays likewise might explain why the bird community that tolerates relentless compressor roars overall reproduces more successfully than the quiet community. Ability to cope or not has rejiggered the dynamics of the bird mix.

The living city

The inevitable species in all of these mixes is Homo sapiens. Humans, for all their generosity with garbage, have a dark side as far as a bird is concerned. They’re not just predators, they’re opinionated predators with technology.

Crow shooting, for example, used to be much more common around Ithaca. McGowan hypothesizes that crows living in the city now descend from those that were willing to take a chance and move closer to people as shooting waned. Several decades ago, old-timers told him that crows hardly ever appeared in town. These days, he and Clark have banded more than 2,000.

Crows may have gotten cozier with people, but the birds don’t forget insults. Crows even appear to recognize and remember the faces of upsetting humans, Marzluff and his colleagues reported in Animal Behaviour in 2010. Marzluff and other experimenters trapped wild Seattle crows just once while wearing rubber masks sold on the Internet as caveman faces. More than two years after the incident, people of various genders and ages and with different body sizes and walking gaits attracted shrieking, dive-bombing crows when wearing the masks. Yet the same people could walk unmasked with hardly any attention from crows.

Crows can even learn grudges from other crows, the Marzluff team reported in June online in the Proceedings of the Royal Society B. Five years after the original trapping episode, crows that weren’t among the offended birds — and crows that weren’t even hatched at the time of trapping — now scold people wearing the masks. The tendency to mob someone wearing the dangerous face has become twice as common at some Seattle sites and spread at least a kilometer from the original study area, apparently via crow information networks.

Crows are celebrated as clever birds, but some capacity for distinguishing among individual people has even turned up among birds of more humble reputation: free-ranging pigeons. When two similar-looking people wearing coats of different colors routinely set out food in a park in Paris, the pigeons could still tell the friendly one from the one that chased them even when the people switched coats, Ahmed Belguermi of Université Paris Ouest and colleagues reported online in Animal Cognition in June. Birds hopping around sidewalks and city parks know about more than human clothing. When Clark is viewing an especially edgy bird, she sometimes puts it at ease by facing off at an angle and pulling out her cell phone for a mimed conversation. Crows seem to assume that people on cell phones ignore their surroundings.

Such studies of urban birds are telling a nuanced tale of animal reactions to previously unencountered environs. A casual observer might assume that animals thriving in the city are just the oblivious, bold species that don’t happen to notice or care if people tramp among them. But that doesn’t appear to be the case.

Instead, Clark says, “living in a city is probably very cognitively complicated.” A bird in the country seems to flourish with just a few simple rules about humans. “People — bad! Fly away!” as she puts it. To survive among the urban wonders and terrors, though, metropolitan animals are using their native cognitive abilities to distinguish the opportunities from the perils. In the city, it’s caveman — bad, Subaru driver — good.

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Science & the Public: Growing need for space trash collectors

Greenhouse gas, solar slowdown are lengthening the lifetime of space debris — increasing its threat to satellites and astronautsWeb edition : Monday, August 15th, 2011 Hovering hazardsThe yellow cloud marks orbiting aerospace debris in low Earth orbit. The longer the debris remains in orbit, the longer it can threaten spacecraft.H. Lewis/Univ. of Southampton

On April 2, for the fifth time in less than three years, the International Space Station fired its engines to dodge a piece of orbital debris that appeared on a collision path. Other spacecraft also regularly scoot out of the way of rocket and satellite debris. Such evasive action will be needed increasingly frequently, a new study finds.

Friction between the atmosphere and materials passing through it, known as drag force, offers the only natural means for culling detritus left in orbit by space launches. But the thermosphere is cooling. A resulting drop in its density is cutting this portion of the atmosphere's drag force, thereby increasing the lifetime of orbiting trash (including pieces in that heavily populated band at 800 to 1,000 kilometers).

Space agencies around the world have been discussing a need to actively remove aerospace debris. One reason: The number of pieces has been steadily rising, driven in part by collisions between orbiting pieces of trash or trash and spacecraft. Among the biggest debris multipliers: a spectacular 2009 crash between the dead Russian Kosmos 2251 spacecraft and the U.S. Iridium-33 telecommunications satellite.

Two years ago, aerospace engineer Hugh Lewis of the University of Southampton, England, and his colleagues calculated that within a few decades, space agencies would have to begin culling perhaps five major pieces of debris annually to slow this collision-enhanced growth in the number of orbiting trash particles. But in a paper in the Journal of Geophysical Research, posted online Aug. 10, the Southampton team now doubles that number, pointing out that the thermosphere’s falling density renders the old trash-pickup requirements obsolete.

Climate impacts

The thermosphere does not behave as a gas, explains Lewis. Molecules originating on or near Earth’s surface are propelled upward based on their energy, he observes. With cooling, fewer of them reach satellite (and associated debris) heights.

Growing emissions of carbon dioxide, a greenhouse gas, contribute to the thermosphere’s cooling, the Southampton team points out. The mechanism, Lewis says, appears to be collisions between CO2 and atomic oxygen at high altitudes. Those collisions release heat in the form of infrared energy, which radiates out into space — removing warmth from Earth’s atmosphere.

A drop in the sun’s activity will also cool the thermosphere. Although the new JGR analysis assumed that solar cycles during the next 70 years would roughly match those seen over the past 30, this may prove an overly conservative assumption, Lewis acknowledges. This spring and summer, scientists have been reporting that the current solar cycle is particularly anemic. And solar activity might remain lackluster for the indefinite future.

Upper atmospheric increases in carbon dioxide “is the primary cooling agent of the thermosphere,” observes thermosphere climate scientist John Emmert of the Naval Research Laboratory in Washington, D.C. The Southampton team’s new analyses, he says, “demonstrate for the first time that space climate change has significant consequences for orbital debris proliferation and for debris mitigation strategies.”

Trash collection realities

Although actively removing space trash from orbit “is absolutely desirable,” focusing on how many pieces to remove annually “is sort of a moot point, since we don’t know how to clean up even one,” says Nicholas Johnson, chief scientist of NASA’s Orbital Debris Program Office, at the Johnson Space Center in Houston.

There’s also the issue of relative risk, he says. “Although there is a sort of sandblasting going on in space all of the time, both from man-made and natural debris, we’ve only had two operational spacecraft ever hit by man-made debris (that we know of) that sustained any major damage.” One was the Iridium-33 catastrophe, the other a French satellite hit in 1996 which was temporarily disabled. While not wishing to dismiss the risk of a possible catastrophic impact, Johnson notes that the risk of a spacecraft-killing collision remains rare — and that “even two times a small number is still a small number.”

But even if space engineers were given the go ahead to develop a waste-collection service for space, succeeding would likely take a very long time. “There is nothing on the horizon that either DOD or NASA believes can do the job [space-trash removal] from either a technical standpoint or from a financial one,” Johnson notes. Still, that won’t stop U.S. researchers from formally brainstorming solutions — and on Uncle Sam’s dime.

Johnson notes that the President’s new national space policy, announced last year, for the first time directs NASA and the Defense Department to develop technologies for removing threatening debris. Their challenge is complicated by the fact that no one has decided which trash to target first. And the issue isn’t as simple as it might at first seem.

There is debris in low Earth orbit — between 400 km and perhaps 1,000 km — where the Hubble Space Telescope, International Space Station and some other satellites reside. Then there’s the geosynchronous Earth orbit regime at altitudes of perhaps 36,000 km. Protecting craft orbiting at such vastly different altitudes will require different strategies.

Engineers also will have to decide whether to focus on protecting today’s operational spacecraft over the next decade or two or protecting craft that may orbit a century from now.

If the focus is going to be on protecting future generations, Johnson says, then the priority should be ridding the skies of big pieces of trash — perhaps the car-size multi-ton behemoths that can break up into hundreds (if not thousands) of shards. Shifting the emphasis to current-generation spacecraft, he says, will argue for getting rid of small debris. “If we’re going to lose spacecraft in the next two decades,” he explains, “statistically, we’re going to lose them to small things we can’t track.”

Government agencies are already tracking thousands of large debris particles in low Earth orbit. Another half million smaller ones, between 1 and 10 centimeters, also pose threats. Uncertainties in their paths currently prompt satellite managers to be overly conservative, maneuvering spacecraft to new paths more frequently than is truly necessary, Johnson notes. The only way to limit that, he says, is to improve the tracking of trajectories for small, but potentially spacecraft-killing debris.

Found in: Atom & Cosmos, Climate Change, Earth Science, Environment, Matter & Energy, Planetary Science, Science & Society and Technology

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JediBot uses Kinect to control lightsaber

Stanford University graduate student Ken Oslund reveals that he is the JediBot's father.

(Credit: Video screenshot by Amanda Kooser/CNET)

You spent countless hours locked in lightsaber battles with your buddies while growing up. What happens when there's no one left to play with you because they all have jobs and babies? You make your own Star Wars playmate.

Students at Stanford University programmed a robotic arm dubbed the JediBot. The bright orange arm swings a red foam lightsaber against a human opponent. It gets off surprisingly snappy attacks with some decent robotic muscle behind it.

It's one thing to create an arm that goes on the offensive, but another to build one capable of defense as well. That's where the Microsoft Kinect comes in. The opposing lightsaber is green so that the Kinect sensors can pick up on where it is in space. The JediBot uses that information to plan its defensive maneuvers.

Related link
• A Star Wars video game unlike any other

The robotic arm--which can swing its sword about once every two to three seconds--was created for a 3.5-week Experimental Robotics course. The class also produced a robot that grills hamburgers and even adds the ketchup. The only thing that would make the JediBot better is if it battled you to a draw and then offered you a tasty cheeseburger.

It's about time someone came up with a Star Wars action figure that truly brings the action. All that's missing are the awesome sound effects. Good thing you've been practicing. Wuumph! Zzzsh! Zzzsh!

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Robo-vac, bouncing blender in design finals

The foot-controlled Robo TAP keeps you on your toes.

(Credit: Gyu Ha Choi)

Even if you're not into home appliances, Electrolux's Design Lab 2011 competition is something worth watching, not least because a neat robot vacuum made it to the finals.

After a field of 25 semi-finalists was announced last month, the judges recently narrowed the hopefuls to eight crushworthy concepts.

One is the Robo TAP Cleaner by Gyu-Ha Choi of Handong Global University in South Korea. This design improves upon automatic vacuums like Roomba by giving users more hands-on (well, make that feet-on) control.

Robo TAP makes use of an indoor positioning system as it follows its own route to vacuum household floors. But when you want it to pay attention to a particularly dirty spot, you just tap your foot twice to summon it.

Bounce that thirst away with the Smoobo Blender

(Credit: Roseanne de Bruin)

All you need is a slender remote tucked into your footwear to get its attention. Three taps return it to its previous routine. And if you click your heels together, you get whisked back to Kansas.

As seen in the vid below, there are some out-of-the-box designs among the other seven finalists. One is the Smoobo Blender by Roseanne de Bruin of New Zealand's Massey University.

To make a smoothie, you pour the ingredients into a large ball covered with nodules, and bounce. Interior blades mix it up for a perfect drink. Just don't try to slam-dunk it.

Kent Madden of Carleton University in Canada, meanwhile, dreamed up a portable rotating bagel toaster that runs on sugar crystal batteries--the same power source as the winning entry for 2010, a portable cooking device called the Snail.

Other finalists for this year include a wall-mounted slow cooker and a portable microwave. The winners will be decided in September, and the top designer will bag 5,000 euros (a little over $7,000) and a six-month paid internship at an Electrolux global design center.

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Trash can reborn as cute Android robot

(Credit: M.I.C. Gadget)

If you've always wanted that little Android icon on your phone to come to life, there's hope. Someone from Taiwan has built himself an Android robot--made from a painted garbage can.

Despite its trashy origins, the wheeled robot certainly looks adorable with its rotating arms and LED lights for eyes. All of these actions are controlled via an external remote control. There's even a little port at the back to charge the machine.

This little fella was built using Arduino, an open-source microcontroller board for developing interactive objects. The microcontroller takes commands from the remote control and sends them to the switches used to control the lights and motors of the robots.

Additionally, it has a little screen in front that reads:

Hi! I'm Android, ready to go!

(Credit: M.I.C. Gadget)

The project took three days to finish and cost about $104. Right now, we're visualizing an army of these things rolling toward Apple's headquarters.

(Credit: M.I.C. Gadget)

Here's the video of the little robot in action. Try not to laugh too hard around 3:28.

(Source: Crave Asia via M.I.C. Gadget)

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Water on the edge of the ancestors

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Stone age human ancestors residing near caves at South Africa’s Pinnacle Point (shown) may have learned to track the tides in order to harvest shellfish. Some propose that this type of activity may have played an important role in human evolution.SACP4

In a cave hugging South Africa’s lush southern coastline, Curtis Marean suspects he has cornered a wily Stone Age crew that brought humans back from extinction’s brink. These plucky refugees of continent-wide desolation were able to pull off such a stunning evolutionary turnaround because they got lucky. A coastal oasis near the bottom of the world spread its sheltering arms in the nick of time.

Marean proposes that it was there, where the Arizona State University archaeologist now conducts excavations, that humankind’s mental tide turned sometime between 164,000 and 120,000 years ago. Seaside survivors learned to read the moon’s phases in order to harvest heaps of shellfish — brain food extraordinaire — during a few precious days each month when ocean tides safely retreated.

Tantalizing traces of complex thinking and behavior, including lunar literacy, have turned up at South Africa’s Pinnacle Point, a cave-specked promontory that juts into the Indian Ocean. Chunks of dark red pigment and strikingly beautiful seashells found by Marean’s team in one cave attest to ancient ritual activities. Stone points unearthed in the same cave sport glossy patches, signs that the rock was heated to make it easier to work with. The finds challenge the long-standing view that Stone Age people did not think abstractly and perform complex rituals until about 50,000 years ago.

People chanced upon Pinnacle Point and its dietary bounty, Marean says, only after global cooling had rendered much of Africa barren and uninhabitable. Several genetic studies suggest that modern human numbers throughout Africa plummeted to a few hundred breeding individuals around that difficult time.

“Our excavations may have intercepted ancient people who shadowed the shifting shoreline and are the ancestors of everyone on the planet,” Marean says.

Research on Pinnacle Point’s mussel-seeking moon trackers exemplifies a growing scientific conviction that fish and shellfish have played a largely unappreciated role in brain and mind evolution throughout the history of the Homo genus, which appeared at least 2 million years ago and includes people today. Though several East African savanna sites contain butchered animal bones, signaling carnivorous tastes among human ancestors, some scientists now argue that red meat has been oversold as a dietary staple.

At a meeting of the American Association of Physical Anthropologists, held in Minneapolis in April, researchers argued that ancient menus focused heavily on food from lakes, rivers and oceans. New work presented at the meeting pointed to lakeside fishing in East Africa nearly 2 million years ago, the shoreline shellfish harvesting among Homo sapiens at Pinnacle Point starting more than 160,000 years ago and sea voyages to Pacific Ocean islands by an unlikely group of New World settlers around 12,000 years ago.

Seashells found at a South African cave were probably carried there by early peoples.A. Jerardino and C. Marean/Journal of Human Evolution 2010

Food scientists at the meeting emphasized that nutrients essential for brain growth are much more abundant in fish and shellfish than in red meat or any other food. And grabbing catfish out of shallow waters, not to mention scooping up handfuls of shellfish along the shore, may be far easier than hunting land animals or scaring predators away from meaty carcasses, says archaeologist Jon Erlandson of the University of Oregon in Eugene.

Shellfish collecting and fishing probably began early among members of the Homo genus, Erlandson says. “These foods later could have provided nutrients that enabled the evolution of fully modern brain size and cognition.”

Olduvai gorging

Erlandson suspects that, before Homo sapiens’ Pinnacle Point pursuits, fishing was a catch-as-catch-can affair. Consider ancient cuisine unearthed on the eastern shore of Kenya’s Lake Turkana. Someone there bellied up to an aquatic buffet nearly 2 million years ago, leaving a mess that only an evolutionary scientist could love.

At a site unceremoniously dubbed FwJj20, a team led by anthropologist David Braun of the University of Cape Town in South Africa unearthed butchered remains of fish, turtles and crocodiles. Remains of animals that don’t live in the water but often reside nearby, such as tortoises, birds, giraffes, hippos, rhinos and antelope, also turned up. Stone tools lay among scraped and fractured shells of tortoises and water-dwelling turtles. Several catfish bones bore tool marks made by individuals who cut off the heads of their catches. Whatever members of the human evolutionary family once dined at FwJj20, they needed only basic implements to put catfish and other lake animals in hungry mouths.

“A large rock is probably all that ancient hominids would have needed to catch fish,” Braun said at the anthropology meeting. Even simpler fishing techniques may extend deep into primate prehistory. Orangutans have been found to snatch catfish from shallow ponds bare-handed and chase the finned snacks out of deeper water with poking sticks (SN: 5/7/11, p. 16).

A steady diet of fish would have nutritionally powered brain expansion in early members of the Homo genus, such as the untidy Lake Turkana crowd, in Braun’s view.

SOUTHERN BOUNTYThe distance between a Pinnacle Point cave labeled 13B and the shoreline changed over time. Shellfish collection probably occurred at times when the coast was within 10 kilometers (highlighted below), though the harvest probably changed with sea level.Africa map: geoatlas/graphi-ogre, adapted by Janel Kiley; receding shoreline map: A. Jerardino and C. Marean/Journal of Human Evolution 2010, adapted by Janel Kiley

The Lake Turkana finds leave a sweet taste in archaeologist Kathlyn Stewart’s mouth. In a 1994 study, Stewart, of the Canadian Museum of Nature in Ottawa, concluded that abundant fish, crocodile and turtle remains at five sites within Tanzania’s Olduvai Gorge represented leftovers from hominid meals. Finds at these nearly 2-million-year-old locations, which have yielded fossils of early Homo and a related lineage called Paranthropus, also include butchered bones of land animals, which have received the lion’s share of scientific attention for more than 30 years.

Game hunting occasionally occurred at Olduvai Gorge, Stewart pointed out at the meeting in April, but aquatic foods provided stable, high-quality nutrition. Pollen data and chemical analyses of fossils indicate that hominids began hanging out in marshy areas, eating grasses and papyrus shoots, more than 3 million years ago, Stewart reported. Papyrus marshes feature a lot of fish, shrimp, snails, mollusks and microalgae, which the gorge residents also dined on. “Lake and river margins provided high-quality food to ancient hominids, especially pregnant and lactating females,” Stewart says.

Some researchers argue that a few aquatic munchfests don’t confirm that ancient hominids across East and South Africa fancied fish. Doubters and advocates alike await finds from more digs along African lakeshores and riverbanks.

Coast with the most

Marean suspects that such excavations will demonstrate that an increasing taste for catfish and other water creatures accompanied increases in brain size among early Homo species. Stone Age people exploited that evolutionary endowment at Pinnacle Point, putting their outsized brains together to solve the puzzle of the tides, Marean says.

Protein-rich shellfish, loaded with omega-3 fatty acids crucial for brain development, led to further social innovations, including a move from eating for now to organizing seaside harvests for later, in his opinion. If so, a sense of time needed to plan for the future characterized the human species almost from its start about 200,000 years ago.

Marean’s team previously reported that mounds of brown mussels and local sea snails excavated in one Pinnacle Point cave date to 164,000 years ago, providing the earliest evidence of coastal dwellers scarfing shelled food with relish, if not condiments (SN: 10/20/07, p. 243).

Stone tools from Channel Island sites dating to 12,200 years ago suggest that the first colonizers to the New World may have come by sea.Univ. of Oregon

The researchers have since found that, by 110,000 years ago, limpets and sand mussels joined the menu. Shellfish foragers face their own brand of perils, Marean explains. Mussels, limpets and sea snails live in treacherous rocks that border the ocean. If the tide is not at its lowest, incoming swells can easily knock collectors onto sharp rocks or into the sea.

The cave excavated by Marean’s group sat two to five kilometers inland around 164,000 years ago, when sea levels were lower than today. Early foragers must have scheduled their activities around the best times to go to the coast for shellfish. When tides were high, foragers instead headed inland eight to 12 kilometers to exploit other foods in South Africa’s rich Cape Floral Region. This 90,000-square-kilometer strip curves around the bottom of Africa like a half-smile. Many plants in the Cape Floral Region produce edible geophytes, underground energy-storage organs that swell with carbohydrates at certain times of the year.

Coastal residents dug up geophytes and hunted inland game until the moon issued a call to the sea, Marean proposed at the anthropology meeting. When the sun and moon align, their combined gravitational forces cause daily tides to spring back and forth from extremely low to extremely high levels. Such spring tides, a twice-monthly effect that has nothing to do with the seasons, correspond to full and new moons.

During spring tides, low tides advance by 50 minutes each day. Fishers and other coastal devotees today consult printed tide schedules or programmed watches to coordinate activities with daily tidal rhythms. Pinnacle Point’s Stone Age crowd informally estimated each day’s prime time for shellfish collecting, Marean suggests.

Access to shellfish wasn’t always available during the Stone Age, though. Climate and environmental records indicate that South Africa’s coastline repeatedly advanced and retreated between 195,000 and 123,000 years ago. Thanks to a gently sloping continental shelf off much of the coast, as much as 95 kilo­meters of land was exposed when sea levels retreated during that period, Marean and his colleagues estimate.

Pinnacle Point attracted human visitors when its caves lay within about a day’s walk of the sea, the scientists assert. This off-and-on shoreline access over tens of thousands of years was enough to trigger big lifestyle changes. “Organizing foraging activities around a complicated system of tidal timing had a trickle-down impact on social life,” Marean says.

Abundant shellfish and geophytes made foragers less nomadic, increased birthrates and reduced infant death rates, Marean suggests. Burgeoning Pinnacle Point communities adopted symbolic and ritual behaviors, as well as advanced toolmaking techniques, to express social identities.

Tide tracking’s domino effect on mental and social life may have given modern humans a survival advantage when they met European Neandertals after leaving Africa. Caves overlooking the Mediterranean Sea in southwestern Europe contain remains of fish, seals and dolphins, as well as mollusks, eaten by Neandertals toward the end of their evolutionary run around 42,000 years ago (SN Online: 9/22/08). But these Neandertal caves contain no huge shell heaps that suggest that coastal visits occurred at tidal low points, when masses of mollusks lay exposed, Marean argues.

It seems that hungry Homo sapiens patiently consulted the moon, whereas Neandertals heeded the urgency of their grumbling bellies.

New World sea cruise

Tide tracking at Pinnacle Point led to expanding numbers of people who eventually turned to sea travel to find virgin territory. These seafood-lovers may well have colonized the world.

Starting around 50,000 years ago, ocean voyagers based in Asia fanned out across the Pacific to Australia and points beyond. These mariners have sailed under the radar of many scientists seeking the earliest settlers of the Americas, Oregon’s Erlandson asserted at the anthropology meeting.

Inland sites in North America contain stone points and mammoth bones that have nurtured a decades-old idea: The New World was first colonized by Asian big game hunters who crossed a land bridge to Alaska around 13,000 years ago. A corridor through massive ice sheets ushered these intrepid carnivores into what’s now the United States, where they founded the Clovis culture, named after a New Mexico site that has yielded stone spear points.

It’s now an open question whether the Clovis-first hypothesis will hold up, Erlandson says. In the March 4 Science, he and his colleagues reported that people lived on California’s Channel Islands by about 12,200 years ago. A sea cruise of nine to 10 kilometers was required to reach these ocean outposts.

Three Channel Island sites — seasonal camps, most likely — yielded narrow-stemmed stone points and crescent-shaped implements, lying among bones of seabirds such as geese and cormorants, seals and other sea mammals, and several types of fish. Piles of shells from red abalone, giant chiton, mussels and other shellfish also turned up.

Stone tools found on the Channel Islands look nothing like Clovis points. In an upcoming Quaternary International, Erlandson and Todd Braje of Humboldt State University in Arcata, Calif., argue that stemmed stone points found on the islands instead resemble those that have been found at coastal sites stretching from Korea, Japan and northeastern Russia to North and South America.

These finds date to between 35,000 and 15,000 years ago in Asia, and to as early as 14,500 years ago in the Pacific Northwest, Erlandson said at the meeting, supporting his suspicion that initial New World colonists used canoes or other vessels to navigate along the coast from Asia to the Americas. Stemmed points found around lakes and marshes in western North America look like Channel Island finds, indicating that coastal people not only cruised the open sea but headed inland, possibly to trade for goods with Clovis people, Erlandson says.

“We have to start creating new models of the peopling of the Americas,” he says. “Received wisdom and a good story can inhibit research for decades, as happened with the Clovis hypothesis.”

Inundated evidence

Encroaching oceans also inhibit investigations of humankind’s water-traveling ancestors. A global sea level rise of about 120 meters between 20,000 and 6,000 years ago flooded shorelines and nearby lowlands where ancient populations presumably camped. “Current evidence for Stone Age coastal occupations represents the tip of the iceberg,” Erlandson says.

Yet the patchy evidence available for ancient tide tracking on South Africa’s coast leaves some researchers skeptical. A connection between shellfish harvesting at Pinnacle Point and a rapid transformation in human thinking remains questionable, argues Stanford University archaeologist Richard Klein.

Coastal caves bearing stone tools and seafood remains from more than 164,000 years ago may yet be found, he asserts. And shellfish gathering requires no special knowledge, tools or personal risk if the tide happens to be out. Coastal baboons in Africa collect and eat shellfish. Seagulls drop mussels and other tidal treats on hard ground to break open shells, leaving behind what sometimes looks like human garbage, Klein says. Also, abundant archaeological evidence of fish eating by Europeans and Africans dates to no more than 50,000 years ago, long after brain size had ballooned.

“It will take a long time to test my hypothesis about an ancient coastal adaptation in South Africa,” Marean acknowledges. Prime shoreline camps from long ago undoubtedly lie under­water, “guarded by great white sharks and dangerous currents,” he says.

He and his colleagues are now exploring more caves at Pinnacle Point and have expanded their search to caves on South Africa’s eastern coast. Some of these sites are located where the continental shelf drops steeply and the coast was always near, possibly giving researchers access to ancient camps that never got inundated by the ocean.

Marean looks forward to further encounters with long-dead lunar tide trackers. This is, after all, no fishing expedition.

Found in: Humans

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