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Our World — 19 September 2009

MUSIC: "Our World" theme

This week on Our World: The newly-discovered dinosaur that's a human-sized ancestor of T. Rex ... probing the link between brain cancer and mobile phones ... and searching for wildlife in America's biggest city.

BUFFINGTON: "What you're listening to, these things, have been out here in the world for millions of years. To me it's almost an honor and a privilege to be able to listen to them sing to me."

Those stories, how fish farming is affecting ocean fish, and more.

I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Dinosaur Found in China is Older, Human-Scale T. Rex Ancestor

An international team of paleontologists has reported the discovery of a new species of dinosaur that looks like a miniature version of the fearsome predator, Tyrannosaurus Rex.

You've probably seen T. Rex in a museum or in the movies — 6 tons or so of killing and eating machine, standing 6 meters tall, and 12 meters long from teeth to tail.

Well, now say hello to T's much smaller ancestor.

SERENO: "I'm describing a new species of tyrannosaur – something that's more primitive than the ones we're most familiar with, like Tyrannosaurus Rex, something that's twice as old, and something that comes from China."

Paul Sereno of the University of Chicago writes about the new dinosaur in SciencExpress, the online counterpart of the journal Science.

The new dinosaur, named Raptorex, lived about 125 million years ago in an area that included what is now northeastern China.

Sereno says Raptorex was a miniature version of T. Rex — roughly human size, about three meters long and about the weight of a person — with many of the features that would define the bigger dinosaur tens of millions of years later.

SERENO: "Basically it stole away, in one blow, all of the things that were special to the big guys. We had thought that a lot of these things like the short arms [with] two fingers, maybe the extra fast legs – these things were what evolved in the course of them becoming giants and basically taking over the large, predatory dinosaur role. But no, they're all present in pint-size Raptorex."

The fossil Raptorex skeleton was brought to Paul Sereno by a collector, who had bought it after it had been illicitly excavated. Normally that would mean that the context of the discovery would be lost, but in this case the bones came with part of the matrix, the rock in which it was found.

SERENO: "And in that rock were fish vertebrae and clams the size of your palm stuck right next to the dinosaur bone, and sediment that was sandy and muddy and other kinds of clues and details just like the forensic data from a crime scene. So I knew that I could determine in a very restricted area where that dinosaur came from. And then, where it fits in, in time. And that was important."

Sereno persuaded the collector to donate Raptorex to science, and after further study it will be transferred to a museum in Inner Mongolia, near where the dinosaur lived.

Where and How North America's First Humans Lived

On November 12, 1955, as Albert Miller took a walk through Meadowcroft, his Pennsylvania property, he noticed a freshly dug groundhog hole. He looked at the disturbed earth, and – being an amateur archeologist – saw a chance to prove that Native Americans once lived on his land.

He expanded the hole until he found evidence to support his theory. Eighteen years passed before archeologists excavated the site, but when they did, they discovered the oldest evidence of human habitation in North America. Erika Celeste reports from Avella, Pennsylvania.

CELESTE: For many years, the oldest evidence of human existence in North America dated to 12,000 years ago. But when Albert Miller's property was excavated in the early 1970s, Smithsonian archeologists made a remarkable discovery. According to radiocarbon dating, several artifacts were 16,000 years old.

David Scofield, director of Meadowcroft, says not only did the results put people on this continent 4,000 years earlier than previously understood, but it put them on the East Coast – a place that didn't fit with earlier theories of human migration, from Asia through Alaska and down the West Coast.

SCOFIELD: "And so, it wasn't well received at first because it contradicted what had been understood to be the first people in North America."

CELESTE: But Dennis Stanford, head of paleoarchaeology at the Smithsonian National Museum of Natural History, says the museum has held firm to its original results, which have been confirmed again and again over the years through new equipment and technology.

STANFORD: And so now it's pretty clear to most of us at least, that the dates at Meadowcroft are correct and that they show one of the earliest finds of pre-paleo people was at Meadowcroft, oddly enough it wasn't in British Columbia, or Alaska, or Montana, but Pennsylvania. And that was pretty exciting, to me at least.

CELESTE: Stanford's theory is that people migrated to both sides of the North American continent, and that Meadowcroft's first inhabitants were early Europeans who crossed the Atlantic in boats as they followed game such as seals.

Meadowcroft is located on the side of a hill, under a giant rock shelter, and over the last 35 years, two-thirds of the site has been excavated. Meadowcroft director David Scofield explains that besides its age, the site is also unique because it was used repeatedly over the course of centuries, and each generation left behind artifacts neatly preserved in chronological layers of dirt.

CELESTE: The extensive site has yielded more than 20,000 artifacts either made or modified by people. Archeologists have also found hundreds of thousands of animal and plant remains.

Meadowcroft's director says those finds will help scientists learn more about the diets of various cultures who used the site, the evolution of native species, and even climate change.

SCOFIELD: "Our mission is really to help people understand how people interacted with the environment here and how they used the natural resources to survive and build a better life for themselves. And so that is true of the first people that used the site, the paleo-Indians; it's true of the 18th century native people who were here; it's true of the Europeans who came here."

CELESTE: Because of Meadowcroft's significance in world history, visitors come here from all over the globe, from Japan to Germany, Brazil to Bosnia. And so, Scofield explains, the rock shelter was turned into a working museum.

SCOFIELD: "As the oldest site of human use in North America, this is certainly something that people are interested in standing on the spot where people stood thousands of years ago, 16,000 years ago. That's remarkable a experience just to be there and know what took place at this site thousands of generations ago."

CELESTE: David Scofield says unearthing treasures containing the mysteries of thousands of years of history is what makes archeology truly exciting.

SCOFIELD: "You can speculate and you can excavate in areas where you believe there might be something, but until you actually excavate nobody really knows."

CELESTE: Erika Celeste, for VOA News, Avella, Pennsylvania.

Build Your Family Tree at our Website of the Week

Time again for our Website of the Week, where we showcase interesting and innovative online destinations.

Tracing your family tree, or genealogy, is a practice that's probably about as old as families themselves. It's a popular hobby that used to require painstaking research and carefully inscribed charts drawn according to complex rules.

More than 20 years ago, computer software started to ease the burden. And now you can create your family tree online with the help of a genealogy website, such as
SACKS: "Geni is creating a family tree of the whole world. Users go to the website. They use a fun, simple, graphical interface to start creating their family tree. And then they can invite other family members to participate. And then those family members join that same tree, and they keep expanding it, so it becomes this collaborative family tree."

David Sacks is the founder of, where building your family tree meets social networking.

Unlike a stand-alone genealogy program, helps you link your family tree with those created by other users.

SACKS: "We will actually look to see if any of the relatives in your [family] tree might be in other trees, and we will suggest when these matches occur."

If you do find a common relative, you can merge the family trees together.

Geni's members have already entered 60 million names, and Sacks says 25 million of them are linked together in one massive family tree – a small step toward his goal to creating a family tree for everyone on Earth.

For now, the site is just in English, though more languages are set to be added soon. But Sacks says you can enter information using any character set. He also stresses that privacy protections are built in to Geni.

Basic functions are free to use, though some advanced features require a paid membership at, or get the link to this and more than 250 other Websites of the Week from our site,

MUSIC: Sister Sledge – "We Are Family"

You're listening to Our World, the weekly science and technology magazine from VOA News. I'm Art Chimes in Washington.

Fish Farming Has Impact on Wild Fish Used for Feed

Half of the fish consumed worldwide this year will come from fish farms, according to a new report. It's the first time the aquaculture industry will reach that milestone. But the industry's growth is putting pressure on ocean fish used to feed farmed fish, and the report calls for changes to reduce aquaculture's environmental impact. VOA's Steve Baragona has more.

BARAGONA: Experts say a number of factors are pushing up global demand for fish, including the growing population, household income growth in Asia, and fish's growing status as part of a healthy diet.

Environmentalists have raised concerns over aquaculture, in part because of the amount of wild fish like sardines and menhaden that are caught to produce feed for farmed fish. Even species like tilapia and carp that don't eat other fish as part of their normal diet are often given fish meal or oil to help them grow better, according to lead author Roz Naylor, an environmental scientist at Stanford University.

NAYLOR: "Even with relatively small amounts in the diet for each fish, there are so many fish that it's adding up to be quite a [lot] of fish feeds now going into those sectors."

BARAGONA: Naylor's colleagues included aquaculture experts and environmental scientists – groups, she says, that have not always agreed on this issue. But they worked together to produce the new report, published in the Proceedings of the National Academy of Sciences.

NAYLOR: "What the paper really showed was that as aquaculture continues to grow and consume a larger and larger share of wild forage fish in its feeds, at some point it's going to put pressure on wild fisheries unless substitutes are made available."

BARAGONA: The report looks at substitutes ranging from new, high-tech sources like genetically modified plants or algae raised for bio-fuels; down to more mundane sources like the waste by-products of other fishing industries.

Not all of these substitutes make economic sense right now. But Naylor says policymakers could help drive the market with incentives and regulations. Fish farmers also could be encouraged to raise species that require less wild fish in their feed. And she adds that some coastal nations will need to restrict the amount of fish caught for feed in their waters to avoid putting too much pressure on fisheries that are already exploited to the maximum — and sometimes beyond.

Steve Baragona, VOA News, Washington.

They go by various names — cellular telephone, cell phone, mobile, wireless, handy – and an estimated four billion people use them worldwide.

Each of those phones has a tiny radio transmitter to communicate with the wired telephone network, and for years, scientists have been trying to determine whether those RF, for radio frequency, transmissions might be harmful.

A U.S. Senate subcommittee this week brought together some experts to review the evidence and focus on whether more research is needed.

Not too long ago mobile phones were exotic and expensive, even seemed magical. Now, as subcommittee chairman Tom Harkin noted, we take them for granted.

HARKIN: "I would venture to guess that almost everyone in this room uses a cell phone on a regular basis, and most of us don't give a second's thought that it could harm us in any way."

Measuring that harm is difficult. One problem is that mobile phones have been in widespread use for a relatively short period of time. Israeli researcher Siegal Sadetzki says cancers triggered by environmental factors, such as radiation, may take a decade or more to develop.

SADETZKI: "In the case of brain tumors, it may reach even 30-40 years. For example, the atomic bombs in Hiroshima and Nagasaki occurred in 1945, while the first report demonstrating brain tumors among the survivors was not published until 1994, 50 years later."

Although many studies have been inconclusive, some newer studies are starting to turn up evidence that long-term use of mobile phones may be dangerous. John Bucher is a senior official at the U.S. National Institute of Environmental Health Sciences.

BUCHER: "There have been some hints recently that there is an increase in brain cancers in people who have used these cellular communication devices for a number of years."

Bucher's agency is funding a large scale animal test designed to simulate in rodents the kind of exposure that humans get when using cell phones. But results won't be in until 2013 or so.

In the meantime, Linda Erdreich of the consulting firm Exponent reviewed scientific evidence on potential health hazards and found no proven link.

ERDREICH: "All of the agency reports that assess the evidence using a comprehensive approach reach similar conclusions: that the current scientific evidence does not demonstrate that wireless phones cause cancer or other health effects."

Although quite a few studies have been published, the experts called before the Senate subcommittee saw a need for more research. Among them was Dariusz Leszczynski of Finland's Radiation and Nuclear Safety Authority.

LESZCZYNSKI: "We need international, well-designed, human volunteer studies. These studies should be aimed at proving or disproving whether human bodies respond to mobile phone radiation. In spite of years of research, we still do not have the answer to this basic question."

In the meantime, mobile users who might be worried about the possible effect of emissions from their phones can take some precautions recommended by experts: Use a headset – a wired one is probably safer than a wireless Bluetooth earpiece – or use speakers. Use a low-radiation model handset. Keep the phone away from your body, while talking or between calls. Use text or SMS rather than voice mode. And limit children's cell phone usage, since young brains may be more sensitive to radiation emitted by the phones.

An Urban Wildlife Expedition: New York's Cricket Crawl

Crickets and katydids are part of the natural soundscape almost everywhere in the world. But how much do we really know about these insects, and how many of them are chirping away in major metropolitan regions like New York? To find out, researchers held a "Cricket Crawl," in which "citizen-scientists" took to the parks, waterways, and iconic locales of the Big Apple and reported back on their mobile phones. VOA's Adam Phillips was there.

PHILLIPS: In a conference room deep inside in New York's American Museum of Natural History, Sam Droege is deep in concentration at a computer. An animal and plant monitoring specialist with the U.S. Geological Survey, is Droege is cycling through field recordings of the seven cricket and katydid species volunteer citizen-scientists will be listening for during tonight's "Cricket Crawl." Many will also have these recordings on hand-held digital players for comparison purposes.

DROEGE: "The nice thing about this is that, by organizing all of New York City to count crickets and katydids for us we will get our answers to where they are, and we've also engaged a whole bunch of people who thought before that they heard at night were background sounds with no meaning, and now people are very excited about the fact that 'Oh that's the Jumping Bush Cricket…'"

DROEGE: "Oh, that's the Greater Anglewing."

PHILLIPS: Sam Droege's co-leader on the Cricket Crawl is Liz Johnson, who also manages the museum's Metropolitan Biodiversity program. She is especially hoping to locate Common True Katydids.

JOHNSON: "It used to be really common in New York City area, especially in New York City. And we're hoping that by getting folks out to do the survey this evening that we'll actually find out where in the city it still exists."

PHILLIPS: There are important differences among the 7,500 known species of crickets and katydids — or Gryllidae and Tettigoniidae, as scientists call them. Most katydids are green and tend to live in the trees, where they munch endlessly on leaves. Crickets tend to be brown and live mostly on the ground where they eat grass, leaves, even dead animals.

The males of both groups attract mates through their distinctive calls, which they make by rubbing their wings together. Each species of cricket and katydid has its own song. Droege says that feature will also enables tonight's eleven "expeditions" to find and identify the insects almost anywhere in the New York metropolitan area.

PHILLIPS: It's now 9 p.m., halfway through the Cricket Crawl, and five canoes are paddling through Brooklyn's murky Gowanus Canal. This post-industrial waterway runs past cement factories and garbage-truck garages and is lined with century-old half-sunk barges. It seems an unlikely place to encounter wildlife of any kind, but Rueben Cope is having luck. He looks excited in his green canoe.

COPE: "I heard the Lesser Anglewing just here. But then some guy started unloading his shopping trolley so that noise of the chain sort of confused me it confused me."

BUFFINGTON: "This is the Buffington Expedition. We're at north 40 ..."

PHILLIPS: That's Matt Buffington, identifying the exact position of a jumping field cricket in Manhattan's Madison Square Park for his blogger. An entomologist with the US Department of Agriculture, Buffington has a keen interest in science. But he says most of all, he loves the Cricket Crawl because it exposes New Yorkers to the wild nature in their midst.

BUFFINGTON: "It brings them back to the earth and roots them into their own existence, I think. Just a simple cricket. It brings them back to the fact that we evolved from something too, as did the cricket and the katydid. That's really what sends chills down my spine and the fact that these things have been out here in the world doing this for millions of years. And it's to me almost an honor and a privilege to listen to them sing to me, you know?"

PHILLIPS: By all accounts, the Cricket Crawl was a success. Sightings were reported from over 300 locations throughout the New York area, mostly in the city itself. And researchers could finally confirm that the Common True Katydid is once again alive, well, and chirping in the Big Apple.

I'm Adam Phillips, VOA News.

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That's our show for this week.

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Our program was edited by Rob Sivak. Felicia Butler is the technical director.

And this is Art Chimes inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.