Super Sticky Slingshot
In comic books and movies, Spider-Man flings spider silk from his wrist.
In nature, a family of tiny spiders has taken the web-flinging move to a whole new level.
The ray spiders of South America construct a web and then reel in one central strand until the web is stretched into a cone shape.
When a yummy insect comes close . . . snap! The spider releases the strand and flings the trap (and itself) toward the prey.
Most spider webs are sticky. The garden cross spider’s web is sticky and electric. The spiders coat their web with special glue that gives the silk strands a small electric charge.
This charge makes the web spring outward toward flying insects, like a paper clip jumping toward a magnet!
Hungry, Hungry Alligators
Imagine you’re an egret looking for sticks to build a nest. Over in the murky swamp, you see a couple of branches floating in the water. Perfect! You wade over and . . . SNAP! You’re lunch for a hungry alligator.
Two things make these frogs unusual. First, they look just like dead leaves, which helps them hide from predators. And second, the father frog carries his babies around in his vocal sac. There’s still time to help save the southern species. Find out more at www.savedarwinsfrogs.org.
Goodbye, Darwin’s Frog
We have sad news to report: The frog pictured here is likely extinct. Charles Darwin identified the species in 1834 in Chile, and it was named after him. But in the past few decades, things haven’t gone well for these little guys. A deadly skin fungus seems to have completely wiped out the northern Darwin’s frog (none have been seen since 1980). The southern Darwin’s frog is on the edge of extinction.
Two things make these frogs unusual. First, they look just like dead leaves, which helps them hide from predators. And second, the father frog carries his babies around in his vocal sac. There’s still time to help save the southern species. Find out more at www.savedarwinsfrogs.org.
What animal can freeze solid, then thaw out and hop away? A wood frog from Alaska! Wood frogs are a common sight across much of North America, from Ohio to Canada, and the species is well adapted to winter weather. When the temperature drops below freezing, the frogs don’t eat or move at all. Their hearts even stop beating!
Recent research shows that Alaskan wood frogs are even hardier than their Ohioan cousins. The Alaskan frogs can spend two months at 24.8 degrees Fahrenheit and then thaw out in just two days. The Ohioan frogs needed at least a week to recover. To help prepare their bodies for hibernation, the frogs build up lots of glucose, a type of sugar, in their blood. They also save up the chemical urea, which is also found in human pee. “We’ve never seen the accumulation [of urea] like we’ve seen in these Alaskan frogs. It’s really spectacular,” said Jon Costanzo of Miami University who led the study. A better understanding of how the wood frogs survive freezing could lead to new methods for preserving human organs and tissues.
When the Bees Got Wiped Out
Dinosaurs almost all died out at about the same time: 65 million years ago. Most likely, a giant asteroid or comet hit the Earth, sending up great clouds of dust and debris. This event killed about 80 percent of all species, including dinosaurs and flowering plants.
If many flower species died, it follows that bees probably wouldn’t survive, either. But the fossil record doesn’t contain very many clues that can help tell the ancient bees’ story. Researchers instead compared the DNA of 230 different species of carpenter bees from across the globe to look at how they are related. “The data told us something major was happening in four different groups of bees at the same time,” says Sandra Rehan of the University of New Hampshire. “And it happened to be the same time as the dinosaurs went extinct.”
They found a long period when the bees’ shared ancestors did not evolve. Since bees evolve quickly, that lull most likely meant there weren’t many bees around. In other words, they (almost) got wiped out!
Too Quick to Be RoadkillSwallows in Nebraska seem to have evolved shorter wings to help avoid highway traffic
Highway overpasses look like home sweet home, if you’re a swallow. These birds often build their nests clustered under cement overhangs, which resemble their natural cliff-side habitat. The only problem? Cars. If a swallow can’t dodge traffic quickly enough—SMACK—it ends up as roadkill.
Scientists Charles Brown of the University of Tulsa and Mary Bomberger Brown of the University of Nebraska, a husband-and-wife team, have been studying swallow populations in southwestern Nebraska since the early 1980s. As part of regular expeditions to collect data, the Browns picked up and counted dead birds. Each year, they found fewer and fewer bodies, until in 2012 they picked up just four road kill casualties. But the total swallow population had more than doubled, and the amount of traffic hadn’t changed. What was going on? The answer: natural selection!
“Over 30 years, you can see these birds being selected for their ability to avoid cars,” Charles Brown told ScienceNOW. The road kill birds had longer wings on average than the rest of the population. The Browns concluded that since birds with longer wings tended to get killed, they didn’t have as many chicks, and eventually short wings became the norm. “Probably the most important effect of a shorter wing is that it allows the birds to turn more quickly,” explains Brown. Shorter wings may also help the birds take off faster. It sounds like short and speedy wins the race if you’re a swallow!
It’s a Bird!
It’s a dinosaur!
But is it real?
A chicken-sized creature named Aurornis xui most likely lived in the Jurassic period, 160 million years ago. It looked a lot like a bird‚ with feathers and wings‚ but it also had teeth, lizard-like claws, and a long tail. A remarkably complete fossil of this ancient creature has convinced some scientists that Aurornis is the earliest bird ever discovered.
Pascal Godefroit of the Royal Belgian Institute of Natural Sciences and his colleagues compared the fossil to about 100 other birds and dinosaurs and generated an evolutionary family tree. According to their analysis, Aurornis, or “dawn bird,” sits at the spot where birds branch off from dinosaurs.
But not everyone is convinced that Aurornis should really be called a bird, and others question whether the fossil is even real. Godefroit and his team did not dig up the fossil themselves: they found it in a Chinese museum, which purchased it from a fossil dealer. There’s a chance that the remarkable find was altered or even faked. Hopefully the story that farmers found the original fossil is true!
“To Frisbee Take Ball!”
Chaser the border collie understands some English grammar
How many commands does your dog know? Most dogs know what to do when you say “sit,” “come,” or “stay.” But if your commands get any more complicated, like, “get your muddy paws off the couch!” then the dog has no idea what it means.
Chaser is no ordinary dog. This 9-year-old female border collie knows the names of more than 1,000 toys, including Pancake, Playmate, Chuckles, and Leopard. She can identify balls from among other types of toys, and she can tell toys apart from objects she’s not allowed to play with.
Chaser’s owner, John W. Pilley, is a retired psychologist who taught at Wofford College in South Carolina. He started training Chaser four to five hours every day when she was a puppy. When Chaser was 7 years old, they started working on grammar.
Now, Chaser understands basic sentences, such as “Frisbee take ball.” That phrase means that Chaser should pick up a ball, carry it over to a Frisbee, and drop it. Chaser can also understand the opposite sentence: “To ball take Frisbee.” Pilley can replace “Frisbee‚” or “ball” with any of Chaser’s thousand other vocabulary words, and she almost always grabs the right toy and carries it to the right place.
Pilley sets up his experiments with Chaser to make sure that he isn’t showing the dog the correct thing to do. He typically sits behind a screen or in another room so he can’t see the objects the dog is supposed to identify. That way he can’t accidentally give Chaser any clues.
Is Chaser really a super genius in the dog world? Pilley thinks that most border collies could learn as much as her, if someone is willing to put in the time to train the dog! “She still demands four to five hours a day,” Pilley said. He doesn’t know how far Chaser’s language ability will go, but feels that they are on the frontier. She already knows more words than any other dog on record.
Your turn! What is the coolest trick your dog can do? (If you don’t have a dog, think about one that belongs to a friend or relative.) Tell us all about your dog’s trick and send a photo to email@example.com or: SMART DOG, ODYSSEY, 30 Grove Street, Suite C, Peterborough, NH 03458.
Tamarin monkeys don’t seem to care for Mozart, but what about a song based on the monkeys’ own calls? Composer David Teie of the University of Maryland teamed up with psychologist Charles Snowdon of the University of Wisconsin-Madison to do just that. Teie used his cello and his voice to create two songs just for tamarin monkeys: one calming, and one fearful. A group of 14 monkeys that had never heard music before listened to each song. The calming music made them more relaxed and social, while the fearful song caused nervous behaviors.
Before writing the music, the team identified the types of monkey sounds that cause emotional reactions. Some tones, pitches and tempos are soothing, while others cause anxiety.The same is true for humans. Snowdon explains, “We use legato [long flowing notes without a break between them] with babies to calm them. We use staccato [short choppy notes] to order them to stop… If you bark out, ‘PLAY WITH IT,’ a baby will freeze. The voice, the intonation pattern, and the musicality can matter more than the words.”
Monkeys seem to respond in a similar way to musical content, but they prefer different tones than humans. What’s relaxing to a tamarin monkey may sound a bit like nails on a chalkboard to you! Listen to the songs here: http://www.news.wisc.edu/17030
Your turn! Play each song for a friend without revealing which is calming and which is fearful. Can your friend tell the difference? Do you like monkey music? Why or why not? Tell us your thoughts at firstname.lastname@example.org or: MONKEY MUSIC, ODYSSEY, 30 Grove Street, Peterborough, NH 03458.
Watch a Zebrafish Think
For the first time ever, scientists have captured thought on video in real time!
Watch the video: http://blogs.smithsonianmag.com/science/2013/01/video-see-a-thought-move-through-a-living-fishs-brain/ It looks like a pink and purple grain of rice zipping around a large purple blob. Really, that grain of rice is a thought moving around in the brain of a zebra fish.
Researchers at the National Institute of Genetics in Japan picked the zebrafish for this study because it has a see-through body. By altering the genes of zebrafish larvae, scientists can make certain parts of the fish glow with fluorescence. Since neurons in the brain use calcium to fire, the Saitama University researchers linked a protein to the fish’s genes that glows in the presence of calcium. When neurons fire in the fish’s brain, the protein lights up, and we can see it with the help of a fluorescent microscope. “We can make the invisible visible; that’s what is most important,” said researcher Koichi Kawakami.
Once you’ve got a fish with a glowing brain, how do you know what it’s thinking about? Before recording the thought, the scientists figured out which neurons in the fish’s brain responded to movement. Then, they released a paramecium, a tiny single-celled creature that the fish love to eat. As the paramecium moved, neurons in the fish’s brain lit up in a pattern that matched the fish’s motion.
So what does a fish think about? That’s easy—food!
Great Green-Glowing Zebrafish
In cartoons, you often see pollution depicted as icky green slime. In reality, it can be a lot harder to detect harmful chemicals in our environment or inside our bodies. Wouldn’t it be helpful if pollution actually turned things bright green?
In the case of this tiny zebrafish, it does! Scientists created the fish with a genetic system that responds to certain chemicals by glowing green under a fluorescent microscope. The chemicals are called endocrine disruptors, scary pollutants found in plastics, medicines, and other products. These chemicals can cause reproductive problems in people and animals, and have even turned some male fish into females.
The green-glowing fish lets scientists easily see where the pollutants go inside the body. “It’s often been assumed that these chemicals impact the liver or reproductive organs, but in these fish we’ve identified them in many different tissues, including parts of the brain,” Charles Tyler of the University of Exeter in the United Kingdom told National Geographic. The pollutants also made it into the fish’s heart, eyes, and muscles.
Making a fish glow is much more than just a cool trick. Research with zebrafish will help us learn more about how pollution impacts the human body.
Meet the Alien Horned-Faced Dinosaur
Maybe it’s just more fun to dig up dinosaur bones than it is to puzzle out how they fit together. That could be why some bones sat in a drawer at the Canadian Museum of Nature for over half a century before scientists realized that they belonged to a whole new species of horned dinosaur: the Xenoceratops.
“When we find something in the field, we wrap it up in a large plaster-burlap jacket so the fossils won’t fall apart,” Dr. Michael Ryan of the Cleveland Museum of Natural History explained to National Public Radio. “And those field jackets, as we call them, will sit on the shelves sometimes for dozens of years.” In this case, the bones had been on a shelf since 1958.
Xenoceratops is related to the well-known Triceratops, but has extra horns jutting out from its frill, the big shield-like plate behind its head. “In the museum we found . . . two large pieces of the frill, including one spike,” Ryan told National Geographic. “As soon as I saw them, I recognized it as being different from every other horned dinosaur.”
Xenoceratops, a plant-eater roughly the same size as an elephant, roamed Canada 15 million years before Triceratops. The name comes from the Latin xeno (“alien”) and ceratops (“horned-face”). What a great name for a new dinosaur!
Your turn! No one knows exactly what any dinosaur looked like. Draw a picture of the Xenoceratops send it to us at email@example.com or: DINO-ART, ODYSSEY, 30 Grove Street, Peterborough, NH 03458. We’ll include some of our favorites in an upcoming issue.
Sonar Math and Dolphin Bubbles
Have you ever been in a car at night, surrounded by thick fog? Turning on the high beams doesn’t help the driver see better—the light just bounces off the drops of water in the air. When a dolphin uses echolocation to get around under the water, bubbles are a lot like fog. Instead of scattering light, they scatter sound.
Human-made sonar gets confused in bubbly water, but dolphins seem to get along just fine. In fact, dolphins sometimes create nets or rings of bubbles when hunting. Tim Leighton of the University of Southampton (UK) watched this fascinating dolphin behavior on the Discovery Channel’s Blue Planet series, and knew that something “fishy” was going on. “These dolphins were either ‘blinding’ their most spectacular sensory apparatus when hunting . . . or they have a sonar that can do what human sonar cannot. . . . Perhaps they have something amazing,” Leighton told Discovery News.
Leighton knew that dolphins emit clicks that are not all the same loudness. He wondered if this wasn’t an accident—maybe changing the loudness of each click helps them tell fish from bubbles. Bubbles bounce back sound a lot more energetically than a solid object, like a fish. So a sonar system sending out different types of clicks could use some complicated math to figure out which echoes are bubbles and which are fish. Leighton and his team built a sonar system to do just that—and it worked!
The dolphin-inspired breakthrough could mean advances in sonar technology to help the U.S. Navy detect dangers like underwater mines through bubbly or murky water.
Coyotes in Chicago ... and in Portland, Seattle, and New York City, Too!
You expect to see animals like pigeons, squirrels, and even raccoons in cities. But coyotes? “We used to think only little carnivores could live in cities, and even then we thought they couldn’t really achieve large numbers,” says Stan Gehrt of Ohio State University, who’s been tracking the coyote population in Chicago for 12 years. “But we’re finding that these animals are much more flexible than we gave them credit for and they’re adjusting to our cities.”
Gehrt estimates that about 2,000 coyotes live in the city of Chicago and its suburbs, coexisting with 9 million people and all of their cars, trucks, buildings, noise, lights, and parking lots. The coyotes dine on rodents, rabbits, young deer, geese, bugs, fruit, and our garbage. In the city, people are the only thing higher up on the food chain than a coyote. Despite the dangers of collisions with cars or hunters with guns, urban coyote pups have a five times greater chance of surviving their first year than their rural cousins.
The coyote is the largest predator yet to move into cities, but Gehrt points out evidence that wolves, mountain lions, or even bears are starting to show up in our backyards. As these animals become more and more comfortable living with us, we’ll have to decide how we feel about living right next to them. Though coyotes do us a favor by keeping rodent, deer, and goose populations in check, they also sometimes eat pet cats or small dogs.
What Do You Think?
Field Guide to Urban Wildlife
Learn the secrets of your animal neighbors. Squirrels, robins, flies, mice, raccoons, starlings, bees, and more all call North American cities home, but they often go unnoticed. Julie Feinstein of the American Museum of Natural History in New York City wrote the Field Guide to Urban Wildlife to help us focus on the commonplace and recognize the animals that share our space. Visit http://www.urbanwildlifeguide.net/ to read Feinstein’s blog about her daily encounters with urban wildlife or to buy a copy of the guide.
Boy Finds a Frozen Mammoth
Keep your eyes open when you’re playing outside—you might just find a frozen mammoth! Eleven-year-old Evgeny Salinder, who goes by “Zhenya,” was walking his dogs in northern Russia when he found just that—a mammoth estimated to be 30,000 years old, buried in frozen mud. The creature still had one tusk attached, and is one of the best-preserved mammoths ever found, according to Russian scientists. Sergei Gorbunov, from the International Mammoth Committee, described the process of getting the mammoth out of the ice to the BBC. “We had to use both traditional instruments such as axes, picks, shovels as well as such devices as this ‘steamer’ which allowed us to thaw a thin layer of permafrost. Then we cleaned it off, and then we melted more of it. It took us a week to complete this task.”
The mammoth has been nicknamed “Zhenya,” after the boy who discovered it.
Home for One of Britain’s Rarest Birds
An airshow full of roaring jet engines and crowds of people doesn’t seem like a place a bird would want to live. But in the summer of 2012, a breeding pair of black redstarts took up residence in a temporary building set up outside the Farnborough International Airshow. Experts estimate that only 40 black redstarts remain in the entire United Kingdom, making this one of the country’s rarest birds. After the show was over, organizers planned to leave the building up until the chicks were ready to leave the nest.
Black redstarts tend to live in unusual places. Their natural habitat is the barren, rocky slopes of the Alps. After London was bombed in World War II, the birds moved into the destroyed areas, living among the rubble. Now, conservationists with the group Living Roofs (LivingRoofs.org) are making an effort to create habitats for redstarts on rooftops. Roofs may contain construction rubble and are often seeded with vegetation that redstarts love. It’s a slow process to bring the birds back, but hopefully they will start to see these rocky roofs as home sweet home.
Jet Lag = Brain Damage for Hamsters
What about humans?
Have you ever traveled on a plane across the country? When you got to your destination, you probably noticed that it wasn’t very easy to fall asleep at bedtime or wake up in the morning. You had jet lag! Your body’s circadian rhythm acts like a clock to tell you when you should be asleep, and when you should get hungry. When you change your schedule, it takes the clock a few days to adjust.
What if you never really let your clock adjust? Pilots, world-traveling executives, and factory workers with rotating shifts often go for long stretches of time without a regular sleeping and waking schedule.
Erin Gibson of the University of California, Berkeley, wondered how messing with the body’s clock again and again like that affects the brain and thinking patterns. To find out, her team recruited some hamsters.
Gibson and her team didn’t actually send hamsters flying around the world. They created the effect of a long flight in the lab, by mimicking sunrise six hours earlier than usual. If you traveled from New York City to Paris, you’d experience the same shift. Every three days for a full month, the hamsters’ schedule shifted another six hours, basically putting the animals in a permanent state of jet lag.
The result? After a month of changing schedules, the hamsters had trouble with basic learning exercises that are easy for normal hamsters. Plus, the jet-lagged hamsters’ brains (specifically, the hippocampus, the area responsible for learning and memory) produced half as many neurons as before the experiment.
Gibson told Science News that jet lag “is having a long-term effect on learning and memory.” More research needs to be done to see if this effect applies to people, too! What do you think? Have you ever been jet-lagged? How did it feel?
Send your thoughts to firstname.lastname@example.org or: JET LAG, ODYSSEY, 30 Grove Street, Suite C, Peterborough, NH 03458.
As the Heat Rises, Damsel Fish Learn to Cope
On a broiling hot summer day, you can hop in a pool or the ocean to cool off. But what is a fish supposed to do when the water heats up? Global warming is slowly increasing the temperature of the world’s oceans, and by 2100, our oceans will likely be three degrees warmer on average than they are now. You may enjoy swimming in warmer water, but to coral and fish, those extra degrees could spell doom.
Or maybe not. Damsel fish, at least, have demonstrated that they can adjust to warmer water. If you put a regular damsel fish in water that’s warmer than it likes, the fish can’t swim as fast and has trouble avoiding predators. But new research shows that damsel fish can get used to temperature changes. “When we bred the fish for several generations at higher temperatures, we found that the second generation offspring had almost completely adjusted to the higher temperatures,” said Jennifer Donelson of the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies. “We were amazed . . . stunned, even.”
The researchers don’t think natural selection or evolution can be the reason for such a quick adjustment. Instead, they think that somehow the parents have transmitted information about the environment to the offspring.
Although this is good news for damsel fish, it doesn’t mean our oceans are safe from global warming. There are many, many species of fish that may not be able to adjust as well or as quickly. And if humans don’t get climate change under control, we’ll have a lot more than just three extra degrees to worry about!
Video Corner: Watch a Horse Run on a Treadmill!
Why in the world is that horse running on a treadmill? For the same reason a human would—exercise. At Rutgers University, scientists want to know how exercise affects a horse’s body, and it’s tough to measure things like heart rate and lung capacity when the horse is running outside. That’s why the Equine Science Center has a high-speed treadmill built specially for horses.
Take a virtual tour of the center to learn about the different tests the horses complete at the Center, and why the researchers are studying horses. You’ll learn that just like us, horses sweat to cool down, and also pump blood and burn calories in a similar way. “When a horse exercises, its body goes through many of the same changes as humans,” says Karyn Malinowski, director of the Equine Science Center. The research her team conducts doesn’t just teach us about horses, it also applies to human medicine! Now, don’t you want to get on a treadmill and run?
Equine — relating to horses
Dolphins See, Hear, Touch, Taste . . . and Detect Electricity!
When you’re looking for tasty fish in the ocean, sometimes eyes and ears just aren’t enough. New research shows that Guiana dolphins detect electricity with dimples on their noses.
This species of dolphin finds most of its food on the sea floor, where rooting around stirs up a lot of muck, making it hard to see. “And echolocation doesn’t work at very close range, so this is where electrolocation would come in,” researcher Wolf Hanke of the University of Rostock, Germany, explained to the BBC News. Echolocation is all dolphins’ tried and true method of hunting: They make sounds, and listen to how the echoes bounce off of things in the water. Electrolocation detects the electricity produced when other animals (or kids!) move their muscles. Many fish, including sharks, have a sensitive sense of electrolocation. But the platypus and echidna are the only mammals other than the dolphin known to have this “sixth sense.” Technically, it’s not a sixth sense for the Guiana dolphin, which has no sense of smell!
Wish you had dimples on your nose for electrolocation? What would you use this sense for? Send your ideas to email@example.com or: ELECTRO SENSE, ODYSSEY, 30 Grove Street, Peterborough, NH 03458.
A Heart That Doesn’t Beat
Abigail is an eight-month-old calf. But something’s strange about her: She has no heartbeat or pulse. An EKG machine would show a flat line, not healthy spikes.
“By every metric we have to analyze patients, she’s not living,” Dr. Billy Cohn of the Texas Heart Institute told NPR. “But here you can see she’s a vigorous, happy, playful calf licking my hand.” How is that possible?
Abigail has an artificial heart that’s different from other hearts. Rather than pumping blood in pulses, it uses two propellers to continuously circulate blood. Cohn compares the breakthrough to the realization that a flying machine doesn’t have to flap. “When man first tried to come up with machines that flew, he looked around and saw bats and birds and butterflies and mosquitoes. Everything had wings that flapped.” By similar reasoning, scientists trying to create artificial hearts have always made hearts with a beat because all living creatures have beating hearts.
Not anymore. Dr. Billy Cohn and his colleague Dr. Bud Frazier implanted their new beat-less heart in a human patient for the first time in March 2011. Craig Lewis, a 55-year-old man, was dying from a disease called amyloidosis that attacked his organs. He had only 12 hours left to live if he didn’t get a new heart.
The doctors made his new heart from two ventricular assist devices—a common medical implant, but one that has always been used alone, and never to replace the entire heart.
“I listened and it was a hum, which was amazing. He didn’t have a pulse,” said his wife Linda Lewis. Sadly, Craig Lewis passed away about a month later—the disease had taken too much of a toll on his other organs. But his new heart worked flawlessly.
His family is glad that his bravery may help future heart patients. We’ll also have to change our thinking: You don’t need a pulse to be alive.
Don’t Pet That Armadillo! You Could Get Leprosy . . .
Leprosy is a scary disease. It causes skin sores and can numb sensation in your limbs. A long time ago, leprosy was untreatable and victims were often shunned from regular society—they lived in leper colonies until they died. Now, a series of antibiotics can cure leprosy, and the disease is almost completely gone in the United States.
Strangely, humans and armadillos are the only animals in the world that can catch leprosy. The bacterium Mycobacterium leprae, the cause of leprosy, is extremely finicky and won’t survive in a laboratory, making it difficult to study the disease. Scientists think that the armadillo’s cool body temperature (90 degrees Fahrenheit) makes it a perfect home for the bacterium, which in humans prefers cooler areas like the fingers, toes, and nostrils.
A team of researchers from Louisiana State University discovered that 22 of 29 leprosy patients in Louisiana shared a very specific strain of the leprosy bacterium with armadillos. In addition, the researchers interviewed 15 of these patients and discovered that eight of them had come in contact with wild armadillos, including one woman who regularly worked in her garden where the animals had been digging (and probably pooping).
“Just by touching an armadillo you’re not going to get leprosy,” study author Richard Truman told Scientific American. About 95 percent of us are immune to leprosy bacteria, and skin contact alone is likely not enough to catch the disease. But . . . it doesn’t hurt to be safe! So next time you see a wild armadillo, keep your distance.
Wacky Fungus Controls Ant-Zombies
Imagine you’re an ant just going about your business on the forest floor in the Brazilian rainforest. Suddenly, something hits you in the head -- it’s a fungal spore-- a single-celled body capable of growing into a new organism. No big deal. Until you start to feel funny -- and then you can’t control your own actions anymore. You start walking like a zombie up a branch to a certain type of leaf, and when you get there, you bite down on the leaf’s underside and die. The fungus begins to grow out of the top of your head, and eventually shoots its own spores at passing ants.
This is not some weird science fiction story; “zombifying” fungi actually exist, and scientists recently discovered four different species. Each species seems to infect one certain kind of ant. “This potentially means thousands of zombie fungi in tropical forests across the globe await discovery,” said David Hughes of Pennsylvania State University.
All four of these newly named species live in the Atlantic Rainforest of Brazil, a rapidly shrinking habitat. Climate change is likely to affect these fungi, because they need an exact amount of humidity to grow. “We’re worried we’ll see the extinction of a species we’ve only just managed to describe,” Hughes told Wired.com.
Besides being totally freaky, these fungi are extremely complex. Scientists do not yet know what chemicals they use to direct ants to specific locations, with the perfect conditions for the fungi to grow. Hopefully we’ll get a chance to learn more about how the ant-zombie fungus works before its habitat disappears.
Feud! How Did Ant and Bee Colonies Really Evolve?
Ants and bees live together in colonies where certain members sacrifice themselves for the good of the group. Biologists call this cooperative behavior eusociality, and they’ve spent a long time figuring out how these eusocial, selfless colonies could have evolved. Normally, evolution is about survival of the fittest, not helping your neighbors. But a theory called kin selection says that if you’re related to someone, their survival matters because they share many of your own genes. So a worker bee that never reproduces and dies protecting its hive is, in fact, protecting its own genes. The more general theory of inclusive fitness says that the benefits of a cooperative action must outweigh the costs.
That all sounds pretty reasonable, right? Not to famous biologist E. O. Wilson (see the April 2007 ODYSSEY), Martin Nowak, and Corina Tarnita of Harvard University in Cambridge, Massachusetts. They published a paper rejecting inclusive fitness and kin selection theory. “After four decades ruling the roost, it is time to recognize this theory’s very limited prowess,” said E. O. Wilson. His basic idea is that close ties to family do not cause colonies to evolve; the family closeness is a consequence. The team developed mathematical models of evolution, one relying only on the theory of natural selection (survival of the fittest) and the other on inclusive fitness. According to their analysis, inclusive fitness seemed unnecessary and limited. “We show that inclusive fitness is not a general theory of evolution. . . ,” said Nowak.
Other biologists couldn’t believe their ears. “I don’t know what’s gotten into E.O. Wilson. They’re attacking kin selection. . . .And they’re wrong -- dead wrong,” Jerry Coyne wrote on his blog. A University of Chicago professor and author of Why Evolution Is True, Coyne was one of almost 150 evolutionary biologists to sign their names to a rebuttal of Wilson, Nowak, and Tarnita’s paper. “We believe that their arguments are based upon a misunderstanding of evolutionary theory,” wrote the group.
Who’s right and who’s wrong? Read the debate yourself at http://news.sciencemag.org/scienceinsider/2011/03/researchers-challenge-eo-wilson.html, then write and tell us whose side you’re on. Send your argument to firstname.lastname@example.org or mail it to: EUSOCIALITY, ODYSSEY, 30 Grove Street, Peterborough, NH 03458.
Dogs Shake It Off; Cats Lap It Up
Wet dogs of all sizes wiggled and shook for the camera in Atlanta, Georgia. In Massachusetts, a cat drinking milk starred in the show. These sound like funny home videos destined for YouTube, but it was all science.
“The [dogs] are shaking at optimal frequencies. I think it’s pretty amazing they can do that,” David Hu of the Georgia Institute of Technology told Science News. Basically, dogs and most other furry mammals have discovered the shaking speed that will dry fur the fastest (and get you soaking wet if you stand too close!). Hu’s team even discovered the math equation for the wet-animal-shake: frequency = radius75. That means that animals with smaller bodies (thus, a smaller radius) have to shake faster (at a higher frequency) to loosen the surface tension of the water. A tiny mouse has to wiggle back and forth 27 times a second (a frequency of 27 hertz), but a huge bear only four times. If mammals couldn’t shake themselves dry, they’d be in danger of hypothermia every time they got wet, Hu explained.
Dogs may be great at shaking, but cats beat dogs at efficiency and elegance when it comes to drinking. You may know from experience that dogs tend to make a mess with a bowl of water, while cats neatly drink it up without even getting their chins wet!
Roman Stocker of MIT noticed the very same thing, but wondered what was involved in the fluid dynamics. So he put his family pet, a gray cat named Cutta Cutta, on camera. “Science allows us to look at natural processes with a different eye and to understand how things work, even if that’s figuring out how my cat laps his breakfast,” Stocker said. The team also filmed a tiger, lion, and jaguar at local zoos. Here’s what they found out: Instead of using the tongue to scoop up a mouthful of milk, cats just brush the surface of a liquid with the top of the tongue, then quickly lift the tongue back toward the mouth, pulling a column of liquid with it. Then the cat nips off the column, and goes back for more. To see this process for yourself in slow motion, touch your finger to a container of marshmallow fluff and lift up, then use another finger to pinch off the string of fluff. Not only is this the cleanest way for a cat to drink, but a cat chooses its lapping speed based on its size. Just like a large dog has to slow down to shake off water efficiently, a big cat has to lap more slowly to drink efficiently.
Try this at home! Film your dog shaking or your cat drinking. Or switch things up: Film your dog drinking and your cat shaking (but don’t dump him in the water!). Email your video to email@example.com with a description of what you discovered. Your work could show up on our Web site!
Hypothermia -- Dangerously low body temperature
In the dark, cold depths beneath Antarctica’s ice, you wouldn’t expect to find anything swimming around -- and neither would NASA scientists. In November 2009, a group of researchers simply wanted to take pictures of an ice sheet’s underbelly to help understand why polar ice is getting thinner. Using hot water, they bored an 8-inch-wide hole into the ice, and lowered a camera on a cable into the hole. Suddenly, a pinkish-orange, shrimp-like creature swam up to the cable! “We were like little kids huddling around, just oohing and aahing at this little creature swimming around and giving us a little show,” said Bob Bindshadler of NASA’s Goddard Space Flight Center in Maryland. “It was the thrill of discovery that made us giddy; just totally unexpected.”
The creature is a three-inch-long Lyssianasid amphipod, not technically a shrimp, though it looks a lot like one. Amphipods typically thrive in icy Antarctic waters, thanks to ocean currents constantly feeding in warmer, nutrient-filled water. But this little guy was swimming beneath the nearly 600-foot-thick Ross Ice Shelf in Windless Bight, 12.5 miles from the open ocean. Either he’s a long way from home, or there’s more going on beneath the ice than scientists ever thought.
“The more we learn about life in ice, the more we become aware that life in Europa or Enceladus or comets or the polar caps of Mars is far more possible than previously thought,” Richard Hoover of NASA’s Marshall Space Flight Center in Alabama told Livescience.com. Hoover wasn’t involved in this discovery, but found a 32,000-year-old species of bacteria living inside Alaskan permafrost in 2005. Finding life in unlikely conditions on Earth increases scientists’ understanding of where to look for life in space.
Bindschadler and his colleagues aren’t done with their camera. In two years, they’re moving on to the Pine Island Antarctic glacier. What do you think they’ll find next time?
Draw a picture! What else is living beneath the ice? Draw the bore hole, and fill it in with whatever creature you can imagine. Email your drawing to firstname.lastname@example.org or mail it to: ODYSSEY30 Grove Street, Peterborough, NH 03458.
Abracadabra, Watch Me Disappear. . .How the Velvet Belly Lantern Shark Turns Invisible
You’re a fish swimming in the ocean, minding your own business. Suddenly, a shadow passes overhead -- a shadow much bigger than you! Swim away quickly, because that dark shape blocking the light means that something big, maybe even a shark, is on the prowl.
Yep, a shadow is a dead giveaway in the open ocean. That’s why some sharks have evolved the ability to glow -- mimicking the sunlight filtering through the water. This is called bioluminescence. More than 10 percent of all sharks have this ability, including the Velvet Belly Lantern Shark, which is nicknamed “the phantom hunter of the fjords” for its brightly glowing belly disguise and its home along the coast of Norway.
Just like magic, there’s no shadow when a Lantern Shark swims overhead. Fish will never see this shark coming, and neither will larger predators. Many bigger, badder fish that like to snack on the 18-inch-long Lantern Shark have upward-looking eyes, so that glowing belly pays off.
But how does it work? And is it only for camouflage? A team of scientists from Belgium captured several Lantern Sharks and kept them in tanks while they measured the intensity of the light coming from special organs on the shark’s belly called photophores. The color and angle of the light matched the sunlight in the fjord where they live. When the scientists adjusted the amount of light over the tanks, the sharks could adjust their camouflage only slightly to stay invisible. It was easy for the sharks to turn on and off, but not to adjust brightness. The team thinks that the sharks may swim deeper during the bright middle of the day -- since the light deeper down won’t be as intense -- and then higher in the evening and at night, evading enemies and catching unaware prey the whole time. That’s what I call a magic trick!
The First Horse Riders
Where in the world do you think the first people managed to tame and keep horses? It wasn’t in Europe or America. We’ll have to travel to the Central Asian steppe to find out more about the history of domesticated horses. Recent research published in the journal Science found three different pieces of evidence pointing to the same conclusion: Horses were tamed about 5,500 years ago by the Botai culture in Kazakhstan, a large country bordering China and Russia. That’s 2,000 years before domestic horses appeared in Europe!
Horses are still central to Kazakh culture. People ride horses, eat horse meat, and drink horse milk in a special fizzy, fermented beverage called koumiss. It turns out all of these traditions may be a thousand years older than archaeologists thought. “The domestication of horses is known to have had immense social and economic significance, advancing communications, transport, food production and warfare,” says the paper’s lead author, Alan Outram of the University of Exeter in England.
Outram and his colleagues looked at excavated horse bones, skulls, and Botai pottery to find their evidence. The bone structures of the ancient horses’ feet resembled later (Bronze Age) domestic horse bones more than wild horse bones from the same time and region. This suggests that the Botai were already keeping and breeding horses. The skulls showed that the Botai rode their horses, too. Five out of 15 skulls showed scarring in the lower jaw where a simple leather bridle was probably looped. Finally, the researchers managed to develop new methods to find traces of fats from horse milk on Botai pottery. “Seventy percent of the sherds we looked at had appreciable fat residues in them,” said Richard Evershed of the University of Bristol in England in a Planet Earth podcast. The tricky part was figuring out what kind of animal the fat came from, and whether it was milk, or meat, fat. It turns out that most of the fat on the pottery was from horsemeat, but about 10 percent of the sherds once held horse milk. Want a taste? Visit Kazakhstan today to try a 5,500-year-old milk drink recipe!
Bird Feeders Split a Species
Does your family feed the birds? You could be changing the future -- the evolutionary future, that is. The Blackcap Warbler, a species of small migratory bird that nests in southern Germany, is splitting into two species. One group migrates southwest to Spain for the winter and the other goes northwest to England. You might be thinking: Wait, they go north for the winter? Isn’t that crazy?Genes determine the direction an individual bird migrates. Before people started putting out bird feeders, any Blackcap Warbler born with migration genes that sent it in the wrong direction wouldn’t survive the winter. But now there are all sorts of tasty treats in English backyards, and there’s an added bonus: The trip to England is only 560 miles, while the trip to Spain is almost twice as far. Because the trip is shorter, the north-migrating birds arrive home in Germany first, and tend to get the best nesting spots and mate with each other.
“This is reproductive isolation, the first step of speciation,” says evolutionary biologist Martin Schaefer of the University of Freiburg. Reproductive isolation occurs when two groups of the same species of birds tend to mate only within their separate groups because of an outside influence that keeps them apart from each other. When Darwin studied finches on the Galápagos Islands, the separation was an ocean. In the case of Blackcap Warblers, people with bird feeders cause the separation! If this separation continues for long enough, the groups may eventually evolve into two distinct species of bird that never mate with each other. It could take 100,000 years to complete the change, though, and Schaefer doubts that people will keep feeding the birds for that long.
However, some changes are already taking place. The north-migrating birds have rounder wings, which make quick turns easier but long-distance flights more difficult. They also have longer, narrower beaks that are better for eating seeds from bird feeders. The south-migrating group has short, fat beaks for eating fruits and olives in Spain.When these two groups do mate, their offspring migrate to southwest France. Schaefer is studying these offspring now to see if they have any trouble surviving. I wonder if the French have as many bird feeders as the British.
Your turn! What do you think the Blackcap Warbler will look like after 100,000 years of evolution? Send your drawing to email@example.com or write to: BIRD OF THE FUTURE, ODYSSEY, 30 Grove Street, Peterborough, NH 03458.
Speciation -- Evolutionary formation of a new species
Best Friends Forever!
Friendship isn’t just for humans, and the benefits go beyond feeling accepted and having someone to chat with about your problems. For female horses, friendship can mean a greater number of healthy babies and less trouble from male horses. Zoologist Elissa Cameron of the University of Pretoria in South Africa studied 55 wild, unrelated mares (female horses) in New Zealand for four years. Cameron and her team collected data on the mares’ social habits, including grooming and hanging out close together. They also kept notes on any aggressive harassment by stallions (male horses). After a whopping 2,000 total hours of observation, the researchers calculated a “social-integration” score for each mare -- which means that they figured out how popular and friendly she was. Surprisingly, this score correlated directly with the horses’ reproductive success rates. The least social mares had only about half as many healthy babies as the most social ones. Also, those pesky stallions tended not to pick on the mares that had lots of friends.
It’s very difficult to prove that friendship directly causes healthier, happier mares and foals (young offspring), because a correlation like this can work both ways: Perhaps the mares with the healthiest babies make more friends. Either way, you can text your BFFs that friendship evolved for a reason: even horses know it!
Think that itty bitty egg at the bottom of the ocean is mindlessly sitting there, waiting to hatch? Actually, it’s watching you! Cuttlefish eggs are encased in black ink when they are first laid, but eventually the translucent eggs swell to the point where the not yet hatched embryo can peer out and watch the surrounding world. And what it sees from inside the egg may determine its favorite food after hatching!
This is the first time science has found evidence of visual learning before birth. Ludovic Dickel and his colleagues at the University of Caen Basse in Normandy, France, chose cuttlefish (which are actually mollusks, not fish) based on previous experiments proving their learning skills as hatchlings, and because of their excellent eyesight, which develops fully before birth.
In the experiment, Dickel harvested wild cuttlefish eggs from the ocean and placed them in several laboratory tanks. One group got a clear view of crabs in a separate tank -- because of the glass walls, there was no way for the embryos to smell or taste their future prey.
As soon as the eggs hatched, researchers moved the baby cuttlefish to a tank out of view of the crabs. After seven days, all the newly hatched hunters were introduced to both crabs and shrimp. In the wild, cuttlefish tend to prefer shrimp. But the cuttlefish that had seen crabs from inside their eggs went straight for the crabs as their favorite food! And the clearer the view of crabs an embryo had, the more it liked to eat them. Baby cuttlefish that hadn’t seen any other creatures while in their eggs liked the shrimp best.
Let’s welcome the world’s newest sub-species of monkey -- Mura’s saddleback tamarin (saguinus fuscicollis mura). The little primate is nine inches tall with a 12-inch long tail, and weighs less than a pound. It managed to remain hidden from the eyes of science in the Amazon River basin until a 2007 expedition. “This newly described monkey shows that even today there are still major wildlife discoveries to be made,” says Fabio Röhe of the Wildlife Conservation Society, lead author of a June 2009 study introducing and describing the new species.
The Amazon River basin is chock full of a surprising number of species -- known and unknown. But local plans for development in the area, including a major highway currently under construction, do not bode well for the newly discovered monkey’s future. “This discovery should serve as a wake-up call that there is still so much to learn from the world’s wild places, yet humans continue to threaten these areas with destruction,” says Röhe.
Hyena Poop Hairballs
Tough luck, mummy, your hair isn’t the oldest of all anymore!
Until now, a 9,000-year-old South American mummy held the world record for the oldest human hair. But thanks to a recent discovery of fossilized hairy remains in ancient hyena poop, that honor now belongs to an unknown hominin who died between 195,000 and 257,000 years ago in the Cradle of Humankind in South Africa. No, hyenas didn’t necessarily eat this early human. Most likely, one of the dog-like creatures found and scavenged a dead body, then took a bathroom break in its usual spot -- inside a cave. Today, thousands of years after this ancient hyena dined and pooped, brown hyenas in Africa still use specific spots in caves as toilets.
A team of researchers led by Lucinda Backwell of the University of the Witwatersrand in South Africa discovered the ancient hyena midden, or toilet, inside a cave and used tweezers to extract forty fossilized hairs that looked like glass needles from one coprolite, the archaeological word for “turd.” Using electron microscopes, the team compared the scales on the hairs to those of many different species, and humans were the closest to a match. Modern humans were just emerging during the time when the coprolites were fresh, so the old hairs may have come from a close relative such as Homo heidelbergensis.
“The oldest known hairs (for all mammals) are found in carnivore feces, permafrost, and amber,” Backwell told Discovery News. She explained that calcium dripping from the cave roof and the additional high calcium content of the hyena poop helped fossilize the hairs and keep them intact for so many years. Now that’s a hairy tale!
Your turn! Have you ever discovered unknown animal hairs in an owl pellet, nest, or elsewhere outside? Did you try to figure out what the hair belonged to? Email your “hairy tale” to firstname.lastname@example.org or write to: HAIRY TALES ODYSSEY, 30 Grove Street, Suite C, Peterborough, NH 03458.
Cradle of Humankind -- An area of about 200 square miles just north of Johannesburg in South Africa with an incredible density of hominin remains. It has been the site for some of the most exciting fossil discoveries since the 1940s.
Meet Ida, Your Long Lost Primate Cousin!
Forty-seven million years ago, a small, monkey-like creature spent her days swinging through the trees of the Messel rainforest in Germany, until she met an untimely death at the edge of a volcanic lake. Her fossilized body was so well preserved that “you can see the fur, the ears, all of the gut contents [leaves and a fruit], all the fingertips and toes,” Holly Smith of the University of Michigan in Ann Arbor told Science News.
Smith is one of a team of international scientists who analyzed Ida’s skeleton and determined that the fossil represents a whole new genus of primates! There’s a bizarre story behind this exciting discovery: Ida was actually unearthed from the Messel pit in 1983, but private collectors split the fossil into two parts. One part wound up in a Wyoming museum, and the more complete part spent 25 years in a private collection before being purchased by Dr. Jørn Hurum for the Natural History Museum of the University of Oslo in Norway. In secret, Hurum brought together a team of international scientists, including Dr. Jens Franzen of the Senckenberg Research Institute in Germany who had previously studied Ida’s Wyoming half. The team realized that the two parts belonged to the same fossil, and began their research of the newly discovered piece. Hurum named the fossil “Ida” after his 6-year-old daughter, and the scientific name Darwinius masillae was given in honor of Darwin’s 200th birthday on February 12, 2009.
Ida lived during a span of time when the “dry nose” haplorhines (an evolutionary branch of primates eventually leading to monkeys, apes, and humans) began to split from the “wet nose” strepsirrhine branch (leading to lemurs, aye-ayes, and bush babies). Although she resembles a primitive lemur, Ida can’t be one because she doesn’t have a toothcomb or toilet claw. She also has finger and toe nails instead of claws, opposable thumbs, and a special foot bone called a talus bone -- all features shared with humans!
While it’s tempting to call Ida the missing link in human evolution, she’s really only one of many, many links between us and our long-lost, tree-swinging ancestors.
Holy Hot Pink Caterpillars. . .
If you want to meet a striped rabbit, a poisonous dragon millipede, or a frog with green blood and turquoise bones, travel on over to the Greater Mekong region in southeast Asia. This corner of the world -- including Cambodia, Myanmar, Laos, Thailand, Vietnam, and some of China -- is packed with fascinating critters. According to a report by the World Wildlife Fund (WWF), 1,068 new species have been found there in just ten years! Here’s the run down: 519 plants, 279 fish, 88 frogs, 88 spiders, 46 lizards, 22 snakes, 15 mammals, four birds, four turtles, two salamanders and a toad. “Who knows what else is out there waiting to be discovered, but what’s clear is that there is plenty more where this came from,” says Stuart Chapman, head of the WWF network’s Greater Mekong Program.
The Greater Mekong is also home to river dolphins, Asian elephants, tigers, Javan rhinos, and the largest freshwater fish in the world: the Mekong giant catfish measuring nearly nine feet long and weighing over 600 pounds. But this biodiversity hot spot is in danger. As the human population grows, factories and farmland threaten local wildlife. The WWF plans to work with local governments and businesses to protect the environment while still helping the economy.
WWF’s report, First Contact in the Greater Mekong illustrates just how rich this region is in newly discovered life. Colorful caterpillars and freaky frogs are only the beginning! Scientists browsing a food market in Laos discovered a species of rock rat everybody thought had been extinct for 11 million years, and officially identified the “new” species in 2005. The world’s largest huntsman spider (Heteropoda maxima), which has up to a foot-long leg span, was also discovered in Laos and named in 2001. A black and white striped krait from Vietnam, Bungarus slowinskii joined the black mamba and spitting cobra in a growing family of super-deadly snakes in 2005. And in 2000, scientists discovered a new mammal -- a truly rare occurrence these days! The furry, black and brown Annamite striped rabbit (Nesolagus timminsi) lives in Vietnam and Laos. And then there’s that dragon millipede (Desmoxytes purpurosea) from Thailand added to the list of new species in 2007. This hot pink, spiny, creepy-crawly protects itself with the deadly poison cyanide! Are you still sure you want to travel to the Greater Mekong?
Blame the Octopus
Who do you blame when an aquarium tank floods? That’s right, the octopus. When the Santa Monica Pier Aquarium staff showed up for work on February 26, 2009, they were greeted with over 200 gallons of spilled saltwater. They didn’t need to call in detectives to figure out whodunit. The culprit was watching the mess from inside her tank, perhaps waving all eight of her suction cup arms in delight!
Octopuses are well known for being intelligent, curious, and strong. This foot-long female California two-spotted octopus had found a valve near the top of her tank and tugged on it, releasing a steady stream of water onto the floor. Thankfully, the staff discovered the disaster before any other creatures in the tank were harmed. “It’s actually quite comical,” said Tara Crow, the Aquarium’s Public Programs Manager. “I think the whole staff is still laughing about the ordeal.” The only bad part, Crow explained, is that the aquarium had just installed brand new, environmentally friendly floors. “Even after two hours of cleaning up we still have salt water seeping up between the tiles every step we take,” she said. Now the curious octopus has lots of extra clamps and tape covering the top of her tank. Next time she’ll have to enlist the help of some razor clams to help her break free so she can do some more mischief!
Chirp! Chirp! Chirp! The rats are laughing again! These lucky rats are part of Dr. Jaak Panksepp’s research on tickling and laughter that he hopes will lead to discovering the source of human joy.Dr. Panksepp, a neuroscience researcher with the College of Veterinary Medicine, Washington State University, observed that rats quickly bonded with researchers who tickled them. To tickle a rat, Dr. Panksepp says he uses “hand play. . . with rapid tickle-type movement of [his] fingers across their bodies.” The tickling action is similar to rat behavior. The resulting laughter sounds like a series of 50 kHz (gigahertz) chirps. Special recording equipment is needed to hear the chirps.
What can we learn from rat laughter? “Lots,” says Dr. Panksepp. “If one has an animal model of an emotional process, one can work out the brain mechanisms.” Tickling and laughter are controlled by the ancient brain systems that humans share with other animals. In fact, rough and tumble play, like tickling and chasing, has been observed in humans, chimpanzees, squirrel monkeys, dogs, and rats.
Play in humans, Dr. Panksepp explains, “probably helps program higher regions of the brain, making us more socially sophisticated and allowing us to learn about our world more effectively.” Tickling rats could lead to a better understanding of how play helps construct parts of the brain.Dr. Panksepp also is looking for the brain chemistries that control the good feelings created by laughter. By studying these brain chemistries, he hopes to find new treatments for depression attention deficit hyperactivity disorder (ADHD).
Ultimately, he would like to track down the gene for joy.
Tickling -- it’s good for so much more than just a laugh!
To see Dr. Panksepp tickling rats, check out “Laughing Rats” on YouTube.com (http://www.youtube.com/watch?v=j-admRGFVNM).
Dolphins: All Work, No Play?
Dolphins may be famous for playing all day, but some of these intelligent sea creatures really know how to get the job done when it comes to finding fish hiding beneath the sandy sea floor. Out of the several thousand dolphins living in Australia’s Shark Bay, 41 mostly female bottlenose dolphins spend up to 17 percent of their time using sea sponges like shovels to sweep yummy fish out of the sand.
“It turns out the brainiacs of the marine world can also be tool-using workaholics, spending more time hunting with tools than any nonhuman animal,” says Janet Mann of Georgetown University in Washington D.C. “This is the first and only clear case of tool-use in a wild dolphin or whale.” Mann has been studying the Shark Bay dolphins and collecting data on their behavior for over 20 years. Although “sponging” was discovered in the 1980s, no one really knew at first why some dolphins carried sponges around in their beaks. Now Mann has not only observed dolphin tool-use first hand, she has documented that mothers pass the behavior on to their daughters.
In every case where Mann observed female “spongers” with their calves, the daughters started sponging within a few years of birth. Sons, however, rarely took up sponging, or if they did, they didn’t start until after weaning. It’s unclear why so many more female dolphins use sponges than males, but it might have something to do with the fact that “spongers” tend to spend more time alone, hunting in deep crevices. It’s important for a female to have strong foraging skills in order to support herself and her calf during the three to eight years of nursing, and this antisocial behavior doesn’t seem to affect a female’s chance for having babies. But having strong social bonds with other males is extremely important to a boy dolphin’s future, so he might ignore his mom’s odd behavior in favor of making new friends!
The Most Ferocious Bite
Imagine a shark gigantic enough to snack on whales, with a bite that could crush a small car. This ancient ancestor of the Great White, Carcharodon megalodon, or megalodon for short, actually swam the seas over a million years ago. At over 50 feet long, and weighing around 50 tons this dude had to be one of the scariest predators ever!
Megalodon means “large tooth” but “large bite” would be just as accurate. Recent research by Dr. Stephen Wroe and his colleagues at the University of New South Wales in Australia used data collected from great whites and computer modeling to show that megalodon had the most powerful bite of any creature ever to live. For comparison, try biting down on an apple as hard as possible. That’s only about 150 pounds of force. An African lion bites with about 1,235 pounds, a T. rex could chomp with 6,834 pounds. . .and the super-shark? Those giant jaws generated 24,000 to 40,000 pounds of crazy bite power! That’s over 100 times more powerful than our favorite great white shark, the star of Jaws.
“I reckon [megalodon] could have crushed a small car,” Wroe told National Geographic News. “Of course it would probably have broken most of its teeth in the exercise.” Those teeth are the real killing tools for the extinct giant fish. Throughout its life, old dull teeth fell out and were constantly replaced by rows and rows of fresh teeth. You could say that its bite was the ultimate in overkill. Megalodon could easily have sliced open a whale with a fraction of all that biting power.
What do sharks and golf balls have in common? Not much unless you zoom in on the golf balls’ dimples and compare them to a sharks’ skin. Despite Jaws’s smooth and sleek look, a shark’s skin is actually studded with millions of tiny scales, called dentricles, which look like little teeth pointing toward the shark’s tail. If you’re brave enough to pet a shark, rub from head to tail! The other direction feels like enlarged sandpaper.
Those little scales may be the secret to sharks’ ability to swim at super speed. The shark speed record belongs to the shortfin mako, which has been clocked swimming at 31 miles per hour. There are estimates that it can actually achieve bursts of up to 45 miles per hour or more, but it’s hard to get a wild shark to volunteer and show off its speed!
Like the dimples on a golf ball, the denticles help reduce drag, as the shark zips through water. Drag is the force of water (or air) resisting a moving object. Amy Lang and her team at the University of Alabama in Tuscaloosa decided to research how, exactly, the scales on a shark’s skin affect the water around the shark to reduce drag and help it swim faster.
Based on evidence that some shark species bristle their scales, or make them stand on end, in order to swim faster, Lang placed a sharkskin-like material with bristled scales in a water tunnel. Thanks to lasers and special materials in the water, the team could see tiny vortices, or swirls, of water form behind the scales. Those swirls act like tiny wheels rolling the shark through the ocean. Imagine rolling a heavy box along on wheels versus pulling it across the floor. Just like the box you drag, a perfectly smooth golf ball or shark would actually have a tougher time speeding along!
Eventually, sharkskin-like material could be used to help save energy on airplanes, ships, or submarine vehicles. So if you want to pet a submarine, better do it now while they’re still smooth!
Lemmings: Boom or Bust?
Warmer winters mean less fluffy snow, and less fluffy snow means hard times for the lemmings of Norway. These little rodents are famous for their huge population bursts and the (untrue) myth that when there are too many lemmings, some will commit suicide by walking off cliffs. Lemming booms used to occur every 3–5 years, but due to global warming, there hasn’t been a population peak since 1994.
Lemmings need light, fluffy snow because the guinea-pig-sized rodents can scamper around in melted spaces beneath the drifts to search for food, mostly mosses and grasses, without predators noticing. Warm winters mean wetter snow and ground often covered in ice, so there’s no place to hide. Predators like the arctic fox and snowy owl used to depend on lemmings’ population booms. Now, they have to search for different prey. Nils Christian Stenseth and colleagues at the University of Oslo in Norway published a study in the November 6, 2008, issue of Nature linking the lemming population decline and climate change.
The study points out that lemmings are still far from endangered, and people in Norway remember what it was like when the population boomed. One commentary on the study pointed out that the numbers were so high in 1970 that people in North Norway used snowplows to clear all the squashed lemmings from the roads!
Hidden Gorilla City
Last year, scientists predicted there might be only about 50,000 western lowland gorillas left in the whole world by 2011. But it turns out our critically endangered primate cousins have a secret city all to themselves -- in the swamp forests of the Republic of Congo in Africa.
A Wildlife Conservation Society (WCS) survey team spent two years tromping through muck and wilderness in those swamp forests, and counted 125,000 gorillas! That’s more than twice the number expected.
Since gorillas don’t exactly line up for role call, the team counted nests -- beds of sticks and leaves that gorillas make every night. Then they used a mathematical model to estimate how many gorillas lived in the area. In the most hidden gorilla city, discovered because of a tip from local hunters, the team found evidence of 6,000 gorillas living close together in a swamp so remote it is impossible for people to reach for over half of the year. The WCS team had to hike through mud for three days to get there!
These high numbers don’t mean we can erase gorillas off the endangered species list. Nest counting isn’t a perfect method for determining creature numbers and there are still lots of threats facing gorillas, including illegal hunting and Ebola (a viral disease that is deadly for both gorillas and humans). Half the surveyed area was already part of national parks or reserves, and the WCS is working with the government of the Republic of Congo to create new protected areas.
“Conservation in the Republic of Congo is working,” says Dr. Steven E. Sanderson, President and CEO of WCS. “This discovery should be a rallying cry for the world that we can protect other vulnerable and endangered species, whether they be gorillas in Africa, tigers in India, or lemurs in Madagascar.”
Three cheers for the gorillas! Now, let’s hope we can leave them alone to enjoy their swamp forest city in peace.
Great Booming Bats!
Have you ever seen a bat swooping silently, using echolocation to find its prey at night?Be thankful your ears can’t hear ultrasonic frequencies or you’d be in for a big, booming surprise. A new study shows that bats roar louder than a rock concert or a fire alarm! Researchers Annemarie Surlykke of University of Southern Denmark in Odense and Elisabeth K.V. Kalko of the University of Ulm in Germany looked at the sounds produced by eleven different species of bats hunting for insects on Barro Colorado Island in Panama. Their results were published in the April 2008 PLoS ONE (Public Library of Science online journal.
Scientists knew bats were loud, but in the lab, bats don’t make quite as much noise as in their natural habitat. In order to measure wild bats, Surlykke and Kalko set up an array of microphones and cameras to record the flying predators. The researchers used their data to reconstruct the bats’ flight paths, then estimated the sound intensity of each cry based on the bat’s distance from the microphone. Most of the sounds ranged between 122 and 134 decibels (db). But the bulldog bat (Noctilio leporinushit) 140 db, a new loudness record for an animal in air! Your home fire alarm screeches at about 108 db, and a rock concert blasts out between 115 and 120 db. Even brief exposure to a sound as loud as 140 db would cause permanent damage to your ears.
Bats need to use high frequencies in order to track tiny insects. But these frequencies fade very quickly in the air, so the louder the sound, the farther away bats can detect prey before the sound fades out. The loudest species of bat also uses the highest frequencies, and can detect a large moth at a range of about 30 feet. I wonder if all that noise drives the other bats batty?
What Do the Whales Think?
We know that whales sing and dolphins play, but are they smarter than humans? The sperm whale wins the prize for the biggest brain on Earth, and dolphins are second only to humans (and tree shrews, which just happen to have very tiny bodies) for the largest brains relative to body size. But neuroscience has shown that the complexity of folds in a brain is more significant than size. One measure of this folding is called the gyrification index. Humans have an index of 1.75, dolphins 2.7, and killer whales score even higher! Dr. Lori Marino of Emory University in Atlanta, Georgia, concluded in a study published in the Public Library of Science journal PloS Biology that cetaceans (marine mammals) show evidence of “complex behavior, learning, sociality, and culture."
The evidence out there is overwhelming. Dolphins recognize themselves in mirrors (see “A Good Look in the Mirror,” ODYSSEY October 2007), learn quickly, imitate humans, and may even give each other names. Killer whales in the eastern North Pacific belong to distinct social groups, and many produce beautiful sounds that are almost definitely a form of language, and perhaps even art. In 2002, the Southwest Fisheries Science Center (SWFSC) identified a sound that had baffled the U.S. Navy for years. Submarine crews had nicknamed the pulsing sound a “boing” when it was first heard in the 1950s off the coast of Hawaii and San Diego, California. Thanks to the SWFSC, we now know that minke whales make this sound, but we still don’t know why. The illustration is a mathematical "wavelet" image by scientist and sound artist Mark Fischer that reveals features of the “boing” invisible to our human ears (see picture, above right).
Another possible measure of smartness based on brain biology is the number of neurons, especially in the neocortex, the area of the brain most responsible for intelligence. Neuroscientists Nina Eriksen and Bente Pakkenberg of the University of Copenhagen counted neurons, and discovered that minke whales have about 12.8 billion, only two thirds of the human neuron count. But there are also 98.2 billion cells called “glia” in the minke whale’s giant neocortex! (Humans have only a small number more glia than neurons.) Recent research suggests that glia may help with information processing. Based on this evidence, researcher R. Douglas Fields, in an article for Scientific American, asks: “Is the whale brain intellectually weaker than the human brain, or just different?” Maybe glia process information in a different way than neurons do, and maybe all those extra glia make whales as smart, or smarter, than humans.
What do you think? Are there whale scientists out there right now discussing their theories on human intelligence? Maybe whales don’t care for science, and create beautiful sound artworks, instead. Or is all this just speculation by us humans, who are desperate for company on the evolutionary ladder? Email your response to email@example.com or write to: WHALE BRAINS, ODYSSEY, 30 Grove Street, Suite C, Peterborough, NH 03458.
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