A fellow who hides in his shell until danger has passed may not seem like the epitome of manliness. Yet among hermit crabs, the shyest males have the most to offer the ladies. It’s all part of their evolutionary strategy. Crabs that are long on bravery, meanwhile, are short on sperm.
Mark Briffa, an animal behavior professor at Plymouth University in the United Kingdom, and his colleagues found the surprising connection between sperm and shyness while studying “life history” in crabs. To a biologist, life history doesn’t mean the material for an animal’s tell-all memoir. Instead, it means how organisms invest their resources. Living things only get a limited budget of food and energy—so is it better to spend that energy growing big and strong, or searching for a mate? Making sperm or eggs, or building large claws or horns to fight off enemies?
The researchers already knew hermit crabs have personality. A little, anyway. Some crabs are bolder, while others spend more time tucked in their shells. And the researchers wanted to know how these personality traits relate to the rest of a hermit crab’s life-history strategy.
Usually, they explain, bolder animals have more reproductive success. They follow a sort of “live fast, die young” plan: if you have the resources, spend them on running around and mating. When you’re eaten by a seagull, at least you’ll leave some young behind. Read More
You won’t see a chickadee shoveling out a parking space and claiming it with a folding chair, no matter how good your binoculars are. But birds, too, have to be resourceful when they live in inhospitable climates. Travel just 600 meters up a mountain, and you’ll find chickadees vastly more clever than their peers living a more comfortable life below.
How do you test the cleverness of birds? Using tubes with tasty worms inside, naturally. Biologists don’t like to call animals “smart,” though, so in this case they were testing the “problem-solving ability” of Poecile gambeli, the mountain chickadee. These songbirds live in the mountainous western United States, ranging from the low foothills to the peaks.
Dovid Kozlovsky, a graduate student at the University of Nevada, Reno, and his coauthors wanted to compare a population of mountain chickadees from a higher elevation, where the weather is more severe, to one from a lower elevation. Read More
Nothing turns your internet procrastination time into feelings of goodwill and teamwork like a citizen science project. You can click through a set of penguin photos or moon craters and know that your data are contributing to real science. As more citizens take part, and more researchers discover the joys of free labor, these projects are gaining popularity. But not all citizen scientists pull their weight. In fact, most do nearly nothing.
Henry Sauermann, a management professor at the Georgia Institute of Technology, is interested in the economics and organization of science. He’s also curious about what motivates scientists. Sauermann and his coauthor, Chiara Franzoni of Politecnico di Milano, thought that citizen science would be “a wonderful new context to think about these general issues,” Sauermann says.
Sauermann and Franzoni gathered data on seven projects at Zooniverse.org, a citizen science web portal. Read More
In a world of shy, quiet-as-a-mouse rodents, one lemming is the exact opposite. It attacks when it should retreat to a hole. It squeals and shrieks when it should keep silent. One scientist is working to figure out how evolution created this animal—and wearing thick gloves while he does it.
First, forget what you think you know about lemmings. You’ve likely heard a rumor that these rodents hurl themselves off of cliffs in droves. It’s not true, though the makers of a 1958 Disney documentary promoted the myth by chasing a bunch of the poor animals into the ocean. Lemming populations do go through wild booms and busts, and lemmings may migrate to new areas when a local population gets out of hand. But otherwise the Arctic dwellers spend their time doing normal rodent things like burrowing, eating grasses, and not committing mass suicide.
Except that the Norwegian lemming, Lemmus lemmus, isn’t quite normal. Read More
“Opinions are my own,” declare countless Twitter profiles. Users want to make it clear that they aren’t speaking for an employer. Yet even when we think our words are our own, our circumstances may speak for us more than we realize.
Microsoft Research scientists Munmun De Choudhury and Michael Massimi studied how Twitter users’ language changes after they get engaged to be married. Actually, the researchers only studied a certain group of engaged people: those who announced their engagement in a public post on Twitter with the hashtag #engaged. Combining data from Twitter with the sharp eyes of Mechanical Turk workers, the researchers found 923 Twitter users who got engaged (and #engaged) between May and December of 2011.
Next, they collected these users’ tweets from before and after they were engaged. Drawing from the 9 months prior to each engagement and 12 months after, they ended up with more than 2 million tweets.
The authors also needed a control group to compare to their engaged tweeters. For this, they sampled tweets from 50 random Twitter users on each day of the study period (spanning both the pre-engagement and post-engagement months of the engaged subjects). This added more than 12 million tweets from more than 11,000 users.
There were striking linguistic differences in people’s tweets before and after getting engaged. Read More
As anyone who’s made valentines for a whole elementary-school class knows, kids are often pushed into social groups not of their choosing. Scientists tried the same thing with wild birds and found it pretty easy to coax them into new cliques. The birds hung out with their new social circles even when they didn’t have to. But once the experiment ended, those friendships dissolved faster than a candy conversation heart.
To create new social groups in birds, researchers essentially controlled which lunch tables they could sit at. Josh Firth and Ben Sheldon of the University of Oxford were studying wild birds in an English forest. As part of an ongoing experiment, there were feeders full of sunflower seeds set up throughout the woods. The birds came to the feeders in mixed-species flocks: great tits, blue tits, coal tits, marsh tits and nuthatches. Then all of a sudden, the birds found that some of these feeders had turned hostile. Read More
While the robot teaching itself to cook is still struggling, here’s a robot that’s nearly mastered another household task: laundry.
Putting dirty clothes into a hamper and moving them to a washing machine isn’t especially hard for humans. But for a robot, the chore is a challenge because it involves some uncertainty.
“The exact number of clothes in the heap and the number that may be picked up with each grasp cannot be determined precisely,” write University of California, Berkeley, computer scientist Siddarth Srivastava and his coauthors. “Doing the laundry thus represents a challenging planning problem.” When you start loading dirty t-shirts into a hamper, you may not know how many there are, or how many trips to the washer you’ll need to take. This probably doesn’t bother you too much. But a robot would prefer to know what it’s doing before it starts. Read More
Minnesota is the “Land of 10,000 Lakes,” at least 13 of which are named Clear. But some of these lakes are clearer and cleaner than others. Does that matter to the tourists who visit them? Researchers found an easy way to answer this question by taking a deep dive into Flickr.
Bonnie Keeler, a scientist at the University of Minnesota’s Institute on the Environment, explains that it’s important to measure how the public is using various lakes, rivers and streams. Agencies that are trying to protect these resources, for example, would love to know that the cost of cleaning up a lake is balanced by the benefit of extra tourism. “We assume that tourists and other users prefer higher quality sites and pristine systems,” Keeler says. But it’s tough to prove, especially in the developing world. Surveying people about their vacations is expensive and hard to do on a large scale.
So Keeler and her coauthors tried to get the information without asking anyone. Instead, they asked people’s photo albums. Read More
We’ve all been there: it’s easy enough to follow our plans to exercise and eat healthily, until suddenly it’s 4:30 in the afternoon and we’re ready to plunge our faces into the first dandelion we see. Honeybees, like humans, can exert self-control when making decisions about food. But when they get hungry enough, that control buzzes right out the window.
For a bee, of course, self-control isn’t about Pilates and salads. Worker honeybees mostly consume nectar. When they get back to the hive they regurgitate that food and share it with the other bees. A responsible worker bee should choose the best nectar sources—not just settle for the first flower she finds—and communicate where they are to her sisters back home.
Researchers have found that honeybees show self-control. They’ll hold out for a larger or sweeter nectar reward instead of drinking a smaller or less sweet reward immediately. But will bees always choose the good of the colony over their own needs? If a bee is hungry enough, will she lower her standards? Read More
Imagine you’re on a particularly boring leg of a road trip and you start counting houses. You pass through long stretches of country without counting anything. When you do see houses, they’re clustered into towns, and may have spacious yards with tire swings. As you approach a city (finally!), rows of houses appear at regular intervals instead of clumping. And in the heart of the city they shrink into little apartments that go by too fast for you to count. European rabbits, it turns out, build their homes in a similar way—and since these animals are disappearing in the countryside, understanding their urban planning strategy matters to humans trying to conserve them.
Hunting, habitat loss, and disease have driven down populations of European rabbits (Oryctolagus cuniculus) in the countrysides of western Europe. Yet rabbit populations in some German cities are, well, hopping. Read More