A cockroach.

CDC, Public Health Information Library

Robots are machines. People build and program them to assemble cars, vacuum floors, or do other tasks. Some venture into dangerous places, such as volcanoes and minefields, where people can’t go safely. Others guard warehouses or simply serve as pets.

Many robots have sensors to detect what’s happening around them. They process this information and react to what they detect.

Scientists and engineers have observed that animals can move and respond in ways that people can’t. Dogs, for example, can hear high-pitched sounds that people can’t hear and smell odors no human nose can detect. Octopuses use a form of jet propulsion to get around and can cram themselves into tiny spaces (see “Walktopus”).

So, it makes sense for researchers interested in robots to learn more about how animals interact with the world around them (see “A Sense of Danger”). Using animals, such as cockroaches and lobsters, as models, they can then try to create robots to do even more things that people can’t do.

Roach navigation

Why would you study a bug to build a robot?

Cockroaches are really good movers, says Noah Cowan. He’s a professor of mechanical engineering at Johns Hopkins University in Baltimore.

Roaches run amazingly quickly for their size. They can dash about in total darkness, creep into tiny crevices, and get around all kinds of obstacles (including the shoes and flyswatters of people trying to squish them).

Because they move so well in difficult conditions, cockroaches could teach engineers how to build robots that can navigate in tight and unlit spaces.

A cockroach has two long antennas with thousands of sensors along each one. Cowan and researchers in his lab focused on how a cockroach uses its antennas to steer.

To find out, they first blindfolded cockroaches and placed them in a dimly lit chamber. Then they used a camera to film exactly how the cockroaches used their antennas as they moved.

It turns out that a cockroach can tell how far it is from a wall by how much its antennas curve as they brush against the obstacle. The insect can then adjust its movements accordingly. It’s the same idea as using your hand as a guide when you walk down a dark hallway. But because your hand isn’t designed for sensing distance, you probably can’t move as fast as a cockroach.

Johns Hopkins student Owen Loh developed this cockroach-inspired robot antenna, which is equipped with six strain gauges to sense bending.

Photo by Will Kirk, Johns Hopkins University

To apply this idea, Cowan and his coworkers built a cockroach-like antenna for a small robot with wheels. Their antenna is made of flexible plastic, which allows it to bend as the robot moves and touches its surroundings.

The antenna is also equipped with several strain gauges. Strain gauges measure how much an object bends. Measurements go from the strain gauges to a computer. A computer program then translates the bending data into distance information that the robot can use to tell how far it is from a wall.

This wheeled robot uses a special, cockroach-inspired antenna to sense walls and other obstacles.

Photo by Will Kirk, Johns Hopkins University

Although it has far fewer antenna sensors and moves more slowly than a cockroach does, the robot steers itself along curves and around obstacles—just like a cockroach in the kitchen.

Cowan isn’t the only robotics researcher who has studied cockroaches to build better robots. Several teams, for example, have created six-legged robots that imitate the way a roach moves it legs, scampers over rough terrain, or evades obstacles. One group has built a roach-inspired machine that climbs walls. Another group has even designed a little mobile robot that’s driven by a live cockroach.

Underwater smells

Like cockroaches, American lobsters have antenna structures that they use to sense the world around them. They also have a second pair of projections on their heads, usually shorter and stubbier than antennas, called antennules.

Using these antennules, lobsters have a particularly good sense of smell, says Frank Grasso. He’s a psychology professor at Brooklyn College.

A lobster’s sense of smell is based on tracking chemicals in the water, and it uses this ability to find food such as clams.

An American lobster, Homarus americanus, has large claws.

OAR/National Undersea Research Program (NURP)

Grasso and his team have spent a great deal of time learning how lobsters trace the odor of food to its source. This information has helped them design, build, and program robots that track the amount of various chemicals in water to their source in the same way that a lobster does.

One resulting robot, named Wilbur, doesn’t look much like a lobster. But it’s mobile and has sensors that respond to the presence of certain chemicals.

Inspired by a lobster’s sense of smell, Wilbur is a chemical-sensing robot.

Courtesy of Frank Grasso

The researchers have tested their “robolobsters” under realistic conditions in the Red Sea. Although they probably weren’t analyzing and responding to smells in exactly the same way that lobsters do, the robots still managed to work as well in the ocean as they do under controlled conditions in the lab.

Such robots may eventually be used to track and pinpoint underwater sources of pollution, detect and locate unexploded mines and bombs, and look for deep-sea vents and other ocean features.

A firm grasp

Another good model for a robot might be the slipper lobster.

Slipper lobsters are covered with large plates and don’t have claws. They’re also not as fast as their American lobster and spiny lobster cousins. “These guys are like Eeyore—slow-moving and lethargic,” Grasso says. “They can go months without eating a clam.”

A slipper lobster in captivity.

Courtesy of Frank Grasso

But when they’re hungry, slipper lobsters walk up to a clam and poke it with their sharp, pointed legs. Without looking, they pick up the clam, turn it to the right position, and put pressure on it to open the shell. Sometimes, they cut a small notch in the shell and pry it open with one of their legs.

Slipper lobsters are a good model for how people grasp and hold things, Grasso says.

In the same way that a person has 10 fingers, a slipper lobster has 10 fingerlike hinges (its legs and the plates). Because a slipper lobster handles clams from the underside of its body, it has to rely on its sense of touch. To do so, it needs to know the position of each leg at all times.

If he could build a robot that could open clams the way a slipper lobster does, he could apply the technology to many other problems, Grasso says.

One result could be an improved artificial hand or a robot that can grasp and manipulate objects with little direction from people.

Imitating nature

Cowan and Grasso are just two members of a large group of researchers who are studying animals to help design, build, and program robots with superhuman abilities. They’re learning a great deal about the animals themselves, and they’re creating ingenious machines that do amazing things.

Developing such robots could lead to the rescue machines of the future. Roboroach could use its antennas to feel its way around obstacles at a disaster scene; robolobster could smell smoke or detect a toxic chemical and follow it to its source. With such help, firefighters and other rescue personnel might be able to save lives without getting hurt themselves.

Going Deeper:

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Now, new evidence supports the notion that ivory-billed woodpeckers are indeed living in the Big Woods area of Arkansas.

The latest hopes for proving that the ivory-billed woodpecker (inset, from 1930s) hasn’t gone extinct come from sound recordings taken in this area, the Cache River Wildlife Refuge in Arkansas, and neighboring territory.

Cornell Lab of Ornithology

Researchers from Cornell University in Ithaca, New York, placed digital sound recorders at more than 150 spots in the woodlands of Arkansas and left them there for weeks. In all, they collected about 18,000 hours of sound.

Within the recordings, the Cornell scientists hear what they say could be the ivory-billed woodpecker’s distinctive sharp calls, which sound like “kent.” The recorders also picked up several dozen examples of a double-knocking sound, typical of the way an ivory-billed woodpecker is supposed to drum on a tree.

On the lab’s Web site (www.birds.cornell.edu/ivory/), the scientists have posted the new recordings, along with recordings from the 1930s. Computer analyses show that the recent calls are very similar to the 1930s sounds, which definitely come from ivory-billed woodpeckers. You can listen to the recordings, compare the sounds, and decide for yourself.

Critics who challenged the first claims (which included seven sightings and 4 seconds of blurry video footage) have been more accepting of the new sound recordings. Still, doubts remain. The bird in the original video looks like a pileated, not ivory-billed, woodpecker to some people.

Moreover, the sounds are not complete proof by themselves, the Cornell scientists say. Several people bird-watching in the Arkansas woods have said that blue jays there sometimes make an odd tooting sound. The recorded calls sound a little like them. To check this, the Cornell team plans to record blue jay calls in Arkansas.

So far, there’s no proof that will satisfy everyone. The only clincher, it seems, will be a clear, close-up photograph. Somebody still needs to take that picture.—E. Sohn

Going Deeper:

Milius, Susan. 2005. What’s that knocking? Sound evidence offered for long-lost woodpecker. Science News 168(Aug. 27):134. Available at http://www.sciencenews.org/articles/20050827/fob8.asp .

Sohn, Emily. 2005. Glimpses of a legendary woodpecker. Science News for Kids (May 11). Available at http://www.sciencenewsforkids.org/articles/20050511/Note2.asp .

Additional information about the ivory-billed woodpecker can be found at www.birds.cornell.edu/ivory/ (Cornell University).

Archaeologists have now uncovered the earliest strong evidence of salt production ever found. It suggests that large-scale salt making occurred at least 4,000 years ago in a settlement in central China.

This aerial view shows a mound beside a river that contains the remains of a site in central China where salt making occurred 4,000 years ago.

Rowan Flad/Proceedings of the National Academy of Sciences

The new evidence comes out of the ruins at Zhongba, a settlement along the salty Ganjing River. Artifacts include pieces of vessels that were used to boil river water. Boiling salty water causes the water to evaporate, leaving behind cakes of salt.

The oldest objects from Zhongba, dating back to between 2000 B.C. and 1750 B.C., include vats with pointy bottoms that were used to either store or boil salt water. From the period between 1630 B.C. and 1210 B.C., the researchers found lots of small cups with pointy bottoms. These were probably molds for making salt cones for trading.

From the period between 1100 B.C. and 200 B.C., the archaeologists dug up small jars with round bottoms. People still use jars like this in some parts of the world to boil salt water and make salt cakes.

Chemical analyses of the river water and of the soil in pits at Zhongba provide further evidence of salt making. Remains inside the round-bottomed jars seem to be calcium oxide, a chemical that forms during the salt-making process. There were also tiny traces of salt inside many of the vessels found at the site.

Learning how to produce large amounts of salt helped the Chinese develop cities and build empires, the scientists say. Back when salt and salted foods were hard to come by, the crystal seasoning was worth a lot, and the Chinese traded it for other goods.

Now that they have the technology to do it, archaeologists want to look for signs of salt making at even older sites in the Middle East. Even as nutritionists today warn that people are eating too much salt, the history of the seasoning has a lot to say about the development of cultures around the world.—E. Sohn

Going Deeper:

Bower, Bruce. 2005. A seasoned ancient state: Chinese site adds salt to civilization’s rise. Science News 168(Aug. 27):132-133. Available at http://www.sciencenews.org/articles/20050827/fob4.asp .

You can learn more about salt and its history at www.saltinstitute.org/38.html (Salt Institute), www.saltsense.co.uk/aboutsalt01.htm (Salt Manufacturers’ Association), and www.historyforkids.org/learn/food/salt.htm (History for Kids).

“There were times when I’d close my eyes and see octopuses because I’d been watching them so many hours a day,” Huffard says. She’s a graduate student at the University of California, Berkeley.

“I’d have dreams that I’d find land octopuses,” she says. Then she wouldn’t have to be in the water all the time, using scuba and snorkeling gear to study them.

Crissy Huffard uses scuba gear and a video camera to study octopuses.

Courtesy of Crissy Huffard

Huffard hasn’t come across any land octopuses yet, but she has made another important discovery. In Indonesia and Australia, she has found two species of octopus that actually walk on two arms.

It’s the first time anything like walking has ever been seen in an animal with no bones. Understanding how octopuses do it might eventually help engineers design “soft” robots that can move in a similar way.

The discovery, Huffard says, also emphasizes just how much there is left to learn about these squishy, eight-armed creatures.

“We’re just now piecing together a lot of aspects of [octopus] behavior,” Huffard says. Although people have been observing octopuses for hundreds of years, “only recently have we had the technology to take video cameras underwater to spend long periods of time with them.”

Jet propulsion

Octopuses normally move around in one of two ways. Sometimes, they funnel water through their bodies, then squirt the water out to propel themselves. They can also crawl on the seafloor by pushing and pulling with suckers on their arms. They have flexible muscles filled with fluid to help them move around.

A small Octopus marginatus sitting on a coconut shell.

Image courtesy of Roy Caldwell, UC Berkeley

Huffard first noticed a walking octopus one day in 2000, while scuba diving in Indonesia. She had spent an entire day following a type of octopus called Octopus marginatus. About the size of a small apple, it’s also known as the coconut octopus.

She was observing its behavior and trying to learn more about its day-to-day life. Oceanographers, meanwhile, filmed the animal.

“At one point, we got close to it with the camera,” Huffard says, “and it just lifted its arms up and started walking. And I thought, ‘That’s really strange.’”

Octopus aculeatus walking over rugged terrain.

C. Huffard, UC Berkeley

A few years later, she observed the same behavior in another species, Octopus aculeatus, while snorkeling off Lizard Island in Australia. Also known as the algae octopus, its body is about the size of a walnut. Huffard then collected more video footage.

Conveyor belts

When she looked at the tapes, Huffard was able to see exactly what was happening. “Immediately, we knew this was different from all other types of octopus locomotion,” she says.

Huffard demonstrating how an octopus can propel itself.

Emily Sohn

Typically, such an octopus moves by drawing six arms around its body and using its backmost pair of arms for propulsion. The two arms take turns bending forward and rolling on the bottom of the ocean, like little conveyor belts, to push the octopus backwards.

Interestingly, researchers in Italy had previously found that they could produce a similar motion in octopus arms that had been cut off. All they had to do was to stimulate an arm with an electrical pulse or bump it. The motion was exactly the same every time.

Based on that work, Huffard and her colleagues suggest that octopuses don’t need to use their brains to walk. Such walking might be just an automatic, or instinctive, behavior.

Masters of disguise

Octopuses are famous as masters of disguise. They can change color rapidly to blend in with their environments. They have muscles under their skin that can make them look spiny or smooth, depending on whether they want to resemble rocks or sand. They can also change their body shapes and squeeze in and out of small holes and other hard-to-reach places.

Walking on two arms appears to be another form of camouflage, Huffard proposes. It’s perfect for when the animals want to move but don’t want to be seen.

O. aculeatus look like blobs of tiptoeing algae when they move quickly. O. marginatus, which live near areas where coconut trees are common, look like fallen coconuts rolling with the current.

Flashy projections on the skin of Octopus aculeatus allow the animal to camouflage itself so that it looks like a blob of algae.

Image courtesy of Roy Caldwell, UC Berkeley

Walking has long been thought to require the combination of muscle pushing against bone. Walking octopuses prove that bones aren’t necessary.

Like walking octopuses, robots of the future may be able to squeeze themselves in and out of small spaces while remaining strong enough to support themselves. Soft robots could be useful in rescue missions and other situations.

A wet life

Huffard, meanwhile, continues to dream about what else her career as an octopus researcher might have in store. She has even grown used to the lifestyle required by the work.

As an octopus researcher, “you spend a lot of time in the water,” she says. “Life proceeds with pruny fingers.”

Huffard adds, “You spend a lot of time away from home and away from pizza and movies and the normal creature comforts that we think of.”

All that sacrifice, though, is worth it, she says, because there’s still so much left to learn about octopuses and the world they live in.

“It’s great because you see something new and different every day,” Huffard says. “And that really motivates me to spend more time in the water trying to understand our marine environment.”

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Now, scientists at Harvard University have found that even tiny algae can be used to do work. Made of just one cell, certain types of algae can drag little objects around, the researchers say. If this skill can be harnessed, algae may someday power tiny machines.

In this algal species, named Chlamydomonas reinhardtii, each rounded cell has two threadlike structures known as flagella, which beat back and forth in a kind of breast stroke to propel the organism.

Algae and other single-celled organisms move with the help of motor-like structures inside their cells. But removing the motors from cells to use them in micromachinery is tough to do. The Harvard scientists, instead, used the whole cells to do work.

First, they created a special molecule with two sticky ends. One end sticks to an algal cell’s body and the other end sticks to plastic. They coated a bunch of tiny plastic beads with this substance.

Next, the researchers put a pile of coated beads in the middle of a track that had been cut into a glass slide. They put a few algae on one end of the track, and they shined a dim light on the other end. Algae are attracted to light, so they swam toward it.

Once the algae got to the middle of the track, they ran into the sticky beads. Each cell picked up one or two of the plastic objects as it kept moving toward the light. Each cell could haul up to its own weight in plastic without slowing down much at all. Some swam as far as 20 centimeters (about 8 inches). That’s 20,000 times the length of their bodies!

Beating its twin flagella, this algal cell lugs a plastic bead through water.

Proceedings of the National Academy of Sciences

To separate the beads from the algae, the researchers shined ultraviolet (UV) light on them, which broke the sticky molecule’s bonds. Then, they used visible light to get the algae to swim away.

Algae will never be as fetching as your pet dog Spot or Fluffy. But they may eventually make your life a bit easier, working on microscopic assembly lines to help construct special microdevices for you and your body.—E. Sohn

Going Deeper:

Brownlee, Christen. 2005. Bitty beasts of burden: Algae can carry cargo. Science News 168(Aug. 20):117-118. Available at http://www.sciencenews.org/articles/20050820/fob6.asp .

You can learn more about Chlamydomonas reinhardtii at www.chlamy.org/info.html (Chlamy Center). You can order materials for science fair projects and classroom lab experiments involving these algae at www.chlamy.org/strains/projects.html (Chlamy Center).

The asteroid 87 Sylvia and its two moons appear in this illustration, along with the sun (far left).

© European Southern Observatory

The asteroid, called 87 Sylvia, is one of the largest in the asteroid belt, a collection of rocky objects that orbit the sun between Mars and Jupiter. The lumpy, potato-shaped asteroid is about 280 kilometers (174 miles) wide.

In 2001, astronomers announced finding a moon orbiting 87 Sylvia, making it one of about 60 asteroids known to have a moon. After the announcement of 87 Sylvia’s first moon, an astronomer from the University of California, Berkeley and several coworkers wanted to see if there were additional moons.

Asteroid moons probably form when large asteroids collide and break apart. Scientists have suspected that the process could end up leaving more than one moon around certain asteroids.

The astronomers looked through 2 months of images of 87 Sylvia. They spotted the second moon in images taken by an infrared camera on the European Southern Observatory’s Very Large Telescope in Chile.

Telescope image of 87 Sylvia and the two moons.

Courtesy Franck Marchis/UC Berkeley and VLT

The first moon measures about 18 kilometers (11 miles) across and orbits about 1,360 kilometers (845 miles) from 87 Sylvia. The newly discovered moon is smaller—about 7 kilometers (4.3 miles) across. It orbits 710 kilometers (441 miles) away.

By analyzing the orbits of 87 Sylvia’s moons, the astronomers were able to learn more about the asteroid itself. Like some other asteroids, it has lots of holes in it. Up to 60 percent of it, in fact, is empty space.

The asteroid and its moons appear to be the result of a collision between two large asteroids. Gravity keeps the lightweight objects loosely bound together. Astronomers call this kind of system a “rubble pile.”

Discovered in 1866, 87 Sylvia was named after Rhea Sylvia, a figure in Roman mythology. In the same spirit, the astronomers who discovered 87 Sylvia’s moons propose naming the moons Romulus and Remus, after Rhea’s two mythical sons who supposedly founded Rome.—E. Sohn

Going Deeper:

Cowen, Ron. 2005. Three’s company: Asteroid 87 Sylvia and her two moons. Science News 168(Aug. 13):101. Available at http://www.sciencenews.org/articles/20050813/fob5.asp .

You can learn more about asteroid 87 Sylvia and its two moons at www.eso.org/outreach/press-rel/pr-2005/pr-21-05.html (European Southern Observatory) and www.berkeley.edu/news/media/releases/2005/
08/10_sylvia.shtml (University of California, Berkeley).

About 83 million miles from Earth, at 1:52 a.m. Eastern time, a projectile released by a spacecraft called Deep Impact smashed into Comet Tempel 1. In Maryland, Lucy McFadden was watching the event with about 50 coworkers. Even though it was the middle of the night, she didn’t feel sleepy at all.

“We were observing on a big screen, and all of a sudden there was a big, bright flash,” McFadden says. “I was stunned. It was just awesome to see. We were jumping up and down.” McFadden is an astronomer at the University of Maryland, College Park.

A bright flash marked the spot where a projectile launched by the Deep Impact spacecraft crashed into Comet Tempel 1.

NASA/JPL-Caltech/UMD

The collision was no accident. Scientists first proposed a comet-slamming mission in 1996, and work on Deep Impact began in 2000. Launched in January 2005, the spacecraft was designed to release a probe that would slam into Tempel 1. The spacecraft would also take pictures and make measurements of the collision. The mission’s goal was to see, for the first time, what comets are like on the inside.

Wild orbits

A comet is a ball of ice, dust, and frozen gas that travels around the sun. A typical comet follows an orbit that brings it close to the sun, then swings it far out beyond the outer planets.

Many comets speed by Earth on a regular schedule. Halley’s comet, for instance, visits our neighborhood every 76 years. Other comets have such wild orbits that they may pass us once but never come back.

When a comet nears the center of the solar system, the sun’s heat vaporizes some of its ice, giving the comet a telltale tail.

Comet Tempel 1, as observed from a telescope at the Kitt Peak National Observatory, shows a bluish ring of gas around the comet and a pinkish dust jet (pointing toward the lower right corner of the image).

Tony Farnham and Matthew Knight, University of Maryland

Ancient cultures noticed comets and either feared or admired them. Some people believed that a comet’s appearance foretold the future, hinting at major events to come on Earth.

These days, astronomers are interested in studying comets for the secrets they might hold about how our cosmic neighborhood was created.

“Comets give us a look back in time to the beginning of the solar system,” McFadden says. “They formed long ago and far away at the edge of the solar system, many hundreds of thousands of times farther away from the sun than Earth is.”

There’s even a hypothesis that water and the ingredients for life were first delivered to Earth when comets struck our planet a long time ago. So, learning more about comets could help us learn more about ourselves.

Space balls

Three previous space missions had flown past comets and taken pictures. But these pictures didn’t reveal what the icy space balls are like on the inside.

For years before the launch of Deep Impact, scientists considered a variety of possibilities. Comets could be dense and strong, hard and brittle, light and fluffy, or soft in the middle with a hard crust on the outside.

Crater expert Peter Schultz and his coworkers at Brown University did experiments to see what might happen to a comet hit by a projectile.

Brown University

To see how each of these types of objects would behave when pummeled, geologist Peter Schultz of Brown University and his coworkers experimented in the lab, building a variety of miniature models of comets out of sand, ice, and other materials.

In a vacuum to simulate space, the scientists used a giant gun to shoot pellets at the artificial comets from different angles. Some of the models exploded into many bits. In other cases, it looked like a space probe would just bury itself in the comet and stop, with no rebound at all.

So, what would happen when a probe actually struck a comet? If the comet were mostly solid ice, the projectile would probably gouge out a small crater. If its surface were like powdery snow, the projectile could even tunnel right through.

“I was hoping that such an impact would form a big curtain of debris that would be ejected after the shock waves hit the surface,” McFadden says. This was the scenario that looked most spectacular and beautiful in the lab.

Impact

When the space probe crashed into Tempel 1, it produced a bright flash. About a second or so later, there was a second flash, and the comet belched out a fan-shaped plume of debris.

This image, which has been colored to highlight important features, shows the plume of material kicked up by the Deep Impact probe’s impact. The comet itself is silhouetted against the light reflected from surrounding dust. The plume was very bright, sugg

NASA/JPL-Caltech/UMD

These observations suggest that the probe ran into fluffy material—very fine dust on the comet’s surface—creating the first flash. The probe then burrowed into the comet and exploded. A high-speed plume of gas blew back out the path created by the probe, creating the second flash. A slower shock wave then reached the surface, releasing a cloud of debris.

By comparing the real explosion to what they had seen in lab experiments, the scientists concluded that Comet Tempel 1 is largely light and fluffy.

“If it were a snowball and you tried to pick it up,” McFadden says, “it would collapse.”

There’s still plenty of analysis left to do. Scientists are now looking through the images frame by frame to peel back the layers of the comet and see how different the inside is from the outside. That might reveal something about how the solar system has evolved over time.

Future mission

Meanwhile, the mission’s work isn’t yet done. Although the probe was destroyed, Deep Impact itself remains in orbit around the sun. It’s currently scheduled to fly past Earth in late December 2007. It may yet get a chance to visit another comet or to set off on some new mission.

A view of Comet Tempel 1′s surface, as seen from Deep Impact’s probe just 90 seconds before it slammed into the comet.

NASA/JPL-Caltech/UMD

If you’re worried about poor, innocent comets getting smashed to bits, don’t fret, McFadden says. First of all, there are billions of comets out there, and comets get hit in space all the time. Most of them are already pockmarked with craters and other features.

Secondly, comets are not as fragile as you might think. Deep Impact’s probe weighed 820 pounds and was about the size of a washing machine. Tempel 1 is about 9 miles long and 2.5 miles wide, or about half the size of Manhattan.

“It was like a gnat running into a 747 jet,” McFadden says. The comet is still moving along on its original path as if nothing had happened.

Keep your ears open for more comet news. A spacecraft called Stardust is on its way back to Earth from the comet Wild 2, where it collected samples in January 2004. It’s scheduled to deliver its load early in 2006.

And, as scientists continue to look at the data from Deep Impact, more surprises are bound to flare up.

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Scientists have recently analyzed the oldest dinosaur eggs ever discovered with embryos still inside. The study suggests that the dinos couldn’t take care of themselves when they first hatched, say the researchers, who come from the University of Toronto at Mississauga in Ontario. Just like human babies, the little dinosaurs relied on grown-ups for help.

The study closely examined two of seven eggs that were discovered 30 years ago in South Africa. The 190-million-year-old eggs belonged to a common plant-eating dinosaur called Massospondylus carinatus, the researchers say. Fully grown, the creatures measured about 5 meters (over 16 feet) long.

Skeletal features of a fossil of a dinosaur just before hatching reveal ungainly proportions and little evidence of teeth.

Illustration by K. Dupuis/University of Toronto, Mississauga

Six of the eggs held bones and other remains that filled their shells. That fact, plus the highly developed state of the bones, suggests that the baby dinos were nearly ready to hatch.

As big as the two embryos were, all of them had empty tooth sockets except one, which only had a single tooth. That means that M. carinatus babies were probably born without teeth or with teeth that were soft and so not preserved as fossils. The scientists say that the youngest of these dinosaurs wouldn’t have been able to bite leaves off of trees. Adults would have had to feed them.

Grown-up M. carinatus walked on two legs. However, the shape of the embryo skeletons made the researchers conclude that the babies traveled on all fours. They had large heads, thick necks, and small pelvic bones, so they would have been awkward and in need of guidance from older, bigger relatives.

Funny enough, dinosaurs that lived later on were built like M. carinatus babies even as adults and grew up to be huge, weighing up to 100 tons and stretching up to 40 meters long. It’s possible that these ancient embryos were an early sign of what was yet to come.—E. Sohn

Going Deeper:

Perkins, Sid. 2005. Young and helpless: Fossils suggest that dinosaur parents cared. Science News 168(July 30):68. Available at http://www.sciencenews.org/articles/20050730/fob3.asp .

Capuchin monkeys have a different experience, a recent study discovered. When these little primates see themselves in a mirror, they know they are looking at something interesting. They’re just not exactly sure what it is.

An adult male capuchin monkey touches his reflection. In the experiment, a mesh barrier separated the monkey from the mirror.

Marietta Dindo

Scientists define an animal as “self-aware” if it touches a painted spot on its own face when it looks in a mirror. People start to recognize themselves in this way at around age 2. Apes and dolphins figure it out in adulthood. Most monkeys, on the other hand, ignore facial markings. They just don’t understand that the image in the mirror is their own.

To find out whether capuchins are self-aware, psychologist Frans B.M. de Waal of Emory University in Atlanta and his colleagues studied eight female and six male monkeys that live at a research facility in Georgia.

Each capuchin entered a test chamber, where it was presented with three different situations. In the first, the monkey saw an unfamiliar monkey of the same sex on the other side of a glass barrier and behind a mesh screen. In the second scenario, the capuchin saw a monkey of the same sex that it was familiar with. Finally, it confronted its own reflection in a mirror behind the screen. The tests lasted for 15 minutes. Each monkey faced each test scenario twice.

When monkeys saw other monkeys that they already knew, they didn’t do much. When shown an unfamiliar monkey, males made threatening gestures. Females looked nervous and avoided eye contact. These were all natural reactions.

When the monkeys saw their own reflections, however, something odd happened. Females looked into their own eyes and acted friendly. They swayed and smacked their lips, as if they were flirting. Males also made more eye contact with their reflections than they did with the animals in the other two scenarios. Unlike females, though, they squealed, curled up on the floor, tried to escape the chamber, and otherwise acted confused and distressed.

The study shows that capuchins have some medium level of self-awareness, de Waal concludes. They don’t quite see the image as another monkey. Nor do they see it as themselves.

Other experts disagree. It is possible, they say, that capuchins simply respond to mirrors as they would to another monkey who won’t stop imitating them. And everyone knows how flattering or annoying a copycat can be.—E. Sohn

Going Deeper:

Bower, Bruce. 2005. Reflections of primate minds: Mirror images strike monkeys as special. Science News 168(July 23):53-54. Available at http://www.sciencenews.org/articles/20050723/fob6.asp .