How to Say “SOS” in Catfish

By Elizabeth Preston | October 3, 2014 9:02 am

catfish

It’s good to have a plan in case of emergency. If there’s a fire, take the stairs to the ground floor. If a bird tries to eat you, say “ERK ERK ERK” by grinding your spine bone against your shoulder bone until it drops you. That latter one will work best if you’re a certain kind of catfish (but feel free to try it and report back).

Our glossary of thorny catfish phrases is getting a little more complete, thanks to Lisa Knight and Friedrich Ladich at the University of Vienna. Thorny or “talking” catfish make up the family Doradidae and are native to South America. Back in 1997, a study by Ladich suggested that these catfish choose their distress calls based on the type of predator that has them in its grasp.

That research thread had since been abandoned. Picking it up again now “happened by chance,” Ladich says. “We had a large number of catfish in our lab,” he explains (who hasn’t been there?), and his student Lisa Knight wanted to investigate their alarm sounds. So the scientists set out to see whether Ladich’s hypothesis from the nineties held up. Read More

Wind Turbines Kill Bats by Impersonating Trees

By Elizabeth Preston | September 29, 2014 2:04 pm

wind farm

Survival tip: don’t hang around machines that have giant spinning blades. It’s a lesson bats have been slow to learn, judging by the large numbers of their corpses found beneath wind turbines. New video footage suggests some bats are attracted to wind farms because they can’t tell turbines apart from trees. If it’s true, this might help us find ways to keep them safer.

“I wish we knew for sure” how big a problem wind farms pose to bats, says USGS research biologist Paul Cryan. Other researchers have estimated that tens of thousands—or even hundreds of thousands—of bats are killed every year by wind turbines in the U.S. and Canada.

Without a good idea of the population sizes of these bats, it’s hard to put those numbers in perspective. But we do know that bats have long lives and reproduce slowly, which makes them vulnerable. “Bat populations do not respond quickly to rapid losses,” Cryan says. And some species of bats seem to die at turbines more often than others, so the danger may not be evenly spread out. The safest solution, Cryan says, is to find ways of stopping bat deaths as soon as possible: “We might have the luxury of time and we might not.” Read More

Walking Really Is Just Falling and Catching Yourself

By Elizabeth Preston | September 26, 2014 9:30 am

lilwalkingdude

The flailing of a gymnast who’s missed a step on the balance beam might not be far off from what the rest of us experience every day. Each step we take is really a tiny fall, a mathematical model suggests. The random-looking variation in our footfalls is actually a series of corrections. Our strides are all screw-ups—but thanks to the fixes that happen without us knowing, our walking routines look like a perfect ten.

Manoj Srinivasan, who runs the Movement Lab at Ohio State University, and Yang Wang, a doctoral student at the time, studied walking down to the millimeter. They put motion-capture markers on people’s feet and pelvises, as if preparing their legs to star in Avatar 3. Then the 10 subjects walked on treadmills at various speeds, while cameras captured every motion.

The data showed that no one was a perfect walker. Read More

CATEGORIZED UNDER: math, physics, screwups, top posts, walking

This Robot Can Plug In a USB But I Still Can’t

By Elizabeth Preston | September 22, 2014 9:00 am

MIT-GelSight-01_0

Why is it that every time I try to insert a USB plug it’s backward? Shouldn’t it be right at least half the time by dumb luck? Whatever my problem is, a dextrous new robot doesn’t have it. The robot’s advantage is that its fingertips don’t just feel—they see, too.

Researchers at Northeastern University and (where else?) MIT created the plug-savvy bot. They started with an existing factory-worker robot called Baxter and gave it a pair of pinching fingers. Then on one finger, they added a shrunken-down and adapted version of a sensing technology called GelSight, invented a few years ago.

GelSight creates a precise sense of touch by, essentially, combining it with vision. It uses a small box (below) surrounding a rubber surface that’s coated in metallic paint. A different color of light shines across the surface from each of the box’s four sides: red, green, blue, and white. Read More

MORE ABOUT: Physics, Robots, Senses

Too Many Penguins Is the Best Kind of Problem

By Elizabeth Preston | September 18, 2014 12:35 pm

hangin out

If you wish your internet procrastination breaks involved fewer weird Facebook relatives and more animal hordes, you’re in luck. The citizen-science enablers at the Zooniverse have just launched a new project called Penguin Watch. You can count penguin babies, squint at rocks, and be back to work before your coffee cools. And help scientists, if you’re into that.

The Zooniverse hosts over two dozen crowdsourced science projects. You can click and scroll through stars, craters, the ocean floor, and even old notebooks to help researchers classify data. (The project called Snapshot Serengeti has already been completed, though, probably because I did half the photos myself.)

The newest dataset comes from remote cameras that are monitoring more than 30 penguin colonies in Antarctica. To participate, users view photos and tag adult penguins, chicks, eggs, and any other animals lurking nearby. The Oxford University scientists behind the project, led by zoologist Tom Hart, say they have about 200,000 images to get through. So I jumped in. Read More

Poop Transplants Let Pack Rats Eat Poison

By Elizabeth Preston | September 15, 2014 11:06 am

WoodratCreosoteByKohl_300dpi2.4MB (1)

Can’t eat poison without dying? Maybe your gut microbes are to blame. Rodents in the Mojave Desert have evolved to eat toxic creosote bushes with the help of specialized gut bacteria. Although scientists had long suspected that bacteria might be key to the rats’ power, they proved it by feeding the rodents antibiotics and ground-up feces.

The desert woodrat or Neotoma lepida lives in dry parts of the western United States. (You might know woodrats as “pack rats”; they build elaborate nests out of debris they’ve hoarded.) In the southern part of the desert woodrat’s range, a bush called creosote grows. Its leaves are coated in a toxic material—the key ingredient, nordihydroguaiaretic acid, normally damages the kidneys and liver of rodents. Yet desert woodrats that live in the creosote bush’s range can eat it without any trouble. In fact, the amount of creosote a desert woodrat eats in just a day would kill a laboratory mouse.

University of Utah biologist Kevin Kohl says it’s “conventional wisdom” that the woodrat’s ability to eat poison comes from the bacteria that live in its gut. But it was difficult to study any animal’s gut microbes before recent advances in DNA sequencing, he says, because most of these bacteria can’t be grown in the lab. Research on gut microbes and toxic foods has usually been done in farm animals, and with just one compound at a time instead of a whole poisonous plant.

Now Kohl captured wild woodrats in Utah to find out what was really happening. Read More

Stop Worrying, Good-Looking Dudes: Your Sperm Is Fine

By Elizabeth Preston | September 11, 2014 8:52 am

dudes

You may have seen headlines over the past week proclaiming that handsome men have lower-quality sperm. If this made you panic because you happen to be a great-looking guy, you can stop. (If you’re an un-handsome man who’s been gloating—sorry.) This scientific study did say a few interesting things about Spaniards, Colombians, and cheekbones. But there was no bad news for good-looking men’s swimmers.

Using male students at the University of Valencia in Spain, researchers searched for connections between good looks and sperm quality. In a 2003 study, the same researchers had already found that more attractive males have better-quality sperm. Now they wanted to confirm that finding while adding a cultural element to the experiment.

After weeding out men with facial hair and various diseases, the researchers were left with 50 subjects. They collected semen samples and photographed the men’s faces from the front and side. The researchers also measured several dimensions of their subjects’ heads that vary between men and women, such as eye size, nostril width, and the proportion of the face that’s below the eyes. Read More

Elderly Seabirds Dive Just as Well as Young Ones

By Elizabeth Preston | September 9, 2014 8:37 am

murres

If your grandma got up from the sofa, did a couple toe-touches, and then ran a mile at her college track pace, she might be approaching the athletic skill of a thick-billed murre. These seabirds make incredibly deep, long dives to catch prey. As they age, their bodies slow and change like ours. But the athleticism of their dives never changes—a feat that might help scientists understand the enigmas of aging.

“Most of what we know about aging comes from lab animals,” says Kyle Elliott, a graduate student at the University of Manitoba. These short-lived flies, worms, and mice tell scientists very little about how long-lived wild animals age and die. Even a wild fly or rodent can expect to end its life as another animal’s meal. But when an animal is likely to live for decades, how does its biology change over time? What eventually kills it? Does cancer or poor cardiovascular health change its life expectancy? “There are certainly an awful lot of open questions,” Elliott says.

To find out a little more, he and his colleagues studied the thick-billed murre, Uria lomvia. These auks have black bodies and white bellies like penguins, but live at the opposite end of the earth. They swim and go diving for food in chilly northern oceans. They can travel as deep as 170 meters and stay under for up to 5 minutes, Elliott says, which is “an amazing feat for a 1-kilogram bird.” Read More

CATEGORIZED UNDER: aging, birds, exercise, the ocean, top posts

Corals Engineer Their Own Currents

By Elizabeth Preston | September 5, 2014 9:58 am

coral starry night

There are few more monastic lives in the animal kingdom than a coral’s. In adulthood it gives up swimming to settle on the ocean floor, surround its spineless body with clones, and become a rock. Mouth facing the ocean, it waits passively for whatever drifts by—or maybe not so passively. Taking a closer look at these creatures, scientists have discovered that corals use their tiny bodies to create swirling currents that are relatively enormous. By forcing the ocean water to move molecules closer or farther away, they work to keep themselves alive.

If you could scuba dive down to a hard coral and zoom in to a microscopic view, you’d see the surface covered in the coral animals’ tiny hairs, called cilia. Many people have looked closely at corals before, in fact—even Darwin studied coral reefs while aboard the Beagle. And some scientists have noticed that the waving cilia keep a thin layer of water moving parallel to the coral’s surface—like “a conveyor belt,” says Orr Shapiro, a postdoc at Israel’s Weizmann Institute of Science who studied corals while he was a researcher at MIT.

This simple swishing can help pull food toward a coral animal’s mouth or carry debris away from the coral’s surface. But beyond that, corals seemed to be at the mercy of ocean currents to bring them gases and nutrients that they need and to carry waste products away. Read More

Pigeon Gamblers Treat Risk Just Like Humans Do

By Elizabeth Preston | September 2, 2014 9:41 am

pigeon slot machine

If you watch poker coverage on television, you probably won’t hear the commentators compare players to pigeons. Maybe they should. The birds don’t play a great game of hold ‘em, but the way they think about risk might be strikingly similar to the way we do.

Researchers discovered this by putting humans and birds through a basic study of risky behavior. “In earlier work, we had tried to recreate some classic behavioral economics results with pigeons, but had failed to do so,” says Elliot Ludvig, a psychologist at the University of Warwick. (You might reasonably ask why he’s studying behavioral economics in pigeons. Don’t worry, we’ll get there.)

Humans are famously “risk averse” for gains. This means that if someone offers us a smaller, guaranteed amount of money (or some other reward), we prefer that to an uncertain but larger amount. For example, given a choice between $50 and a coin flip for $100 or nothing, people usually pocket the $50. But we’re “risk seeking” for losses. If the coin flip is between losing $100 and losing nothing, we’ll choose to gamble rather than just handing over $50. The same thing is true when people choose between a larger gain and a smaller one, rather than a gain and a loss, Ludvig says.

This kind of decision making might seem like a stretch for a bird. But even a lowly pigeon has to make choices all the time about where to search for food. The retiree on the park bench with the bag of stale crumbs is a sure bet; following around a child with a tippy ice cream cone is more of a high-stakes gamble.

Yet Ludvig had struggled to recreate human decision-making results in pigeons. The problem, he realized, was that pigeons don’t have the luxury of language. Researchers can explain a gambling scenario to human subjects (“The odds are one-in-three that there’s a new car behind Door Number One!”), but pigeons have to deduce the odds on their own, through trial and error. Rather than teaching pigeons English, Ludvig decided to level the playing field by making humans take a pigeon’s version of the test.

Researchers gathered a group of human subjects and a small group of pigeons. The pigeons did daily testing sessions for about a week. In each trial, a pigeon walked into a testing arena that held a pair of colored doors. After it chose a door to go through, food was dispensed. It was up to the pigeons to learn the pattern: two possible door colors were high-value (orange meant a safe 3 cups of food, and purple was either 4 or 2 cups) and two were low-value (yellow for a safe 1 cup of food, green for a gamble between 2 and 0).

Humans did their trials all at once on a computer screen, with images of colored doors—but like the pigeons, they had to deduce the rules. The reward wasn’t food pellets but a number of points that flashed on the screen after each choice. Researchers told subjects to try to get as many points as possible.

Classic psychology says people should gamble less often when there’s more at stake. What happened, though, was the opposite. By the end of the experiment, when people had figured out the stakes associated with each door, they picked the risky option about 35 percent more often for the high-value door than the low-value one. In other words, they were more likely to gamble for a higher number of points, and to take the safe option for the lower number.

Pigeons made nearly identical choices to humans. By the final days of the experiment, the birds were choosing to gamble more often on high-value doors than low-value ones. The difference was even the same as in humans: about 35 percent.

Why didn’t people behave as expected? Ludvig thinks the difference is that in older studies, subjects had the options spelled out for them. In his study, people had to figure out the odds through their own experience. (Another difference is that the people in this study played for points, not for real monetary rewards or even for food, like the pigeons did.)

When they don’t learn the rules ahead of time, “people behave similarly to pigeons,” Ludvig says. He thinks the results are relevant to real gambling games like slot machines—or even to the choices we make on a daily basis, like whether to risk getting a ticket by parking illegally while we dash into a store.

Ludvig says the close similarity between human and pigeon results surprised him. It may point to something deep and ancestral in the brain that influences our decision making. “We think that a lot of human choice is driven by basic biases about how people perceive and remember risks and rewards, which we share with many other species,” he says.

By studying these biases, Ludvig hopes to learn more about how we make risky choices. Are certain habits—like leaning toward a gamble when the stakes are higher, or lower—exaggerated in people who are problem gamblers or who behave in other risky ways? When humans won’t reveal why they do what they do, a few hungry birds might help.


Image: by Miss Shari (via Flickr)

Ludvig EA, Madan CR, Pisklak JM, & Spetch ML (2014). Reward context determines risky choice in pigeons and humans. Biology letters, 10 (8) PMID: 25165453

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Inkfish

Like the wily and many-armed cephalopod, Inkfish reaches into the far corners of science news and brings you back surprises (and the occasional sea creature). The ink is virtual but the research is real.
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