When a new developer comes to town and starts aggressively building up the empty property around your home, you can get mad—or you can move in. That’s what tiny crustaceans in the Georgia mudflats have done. Facing an invasive Japanese seaweed, they’ve discovered that it makes excellent shelter, protecting them from all kinds of threats. And where the crustaceans went, a whole ecosystem has followed.
Jeffrey Wright is an ecologist who studies invasive species at Australian Maritime College in Tasmania. He traveled all the way to the southeastern United States to study Gracilaria vermiculophylla, a Japanese seaweed that’s made a name for itself by crashing both coasts of North America as well as northern Europe. Wright had previously studied a similar seaweed in Australia, and was eager to see how this ecosystem compared.
In Georgia and South Carolina, Gracilaria has moved into marshy coastal areas, taking over the mudflats that appear at low tide near the mouths of rivers. Read More
Scientists love the data they get by attaching electronic tags to animals, but these devices can be a literal drag. For animals that fly or swim, tags can mess up their mechanics and force them to spend more energy. That’s what scientists expected to see when they studied dolphins with data loggers suction-cupped to their backs. To their surprise, they found instead that these dolphins refused to work any harder at all.
When scientists attach a data-logging tag to an animal, they try to disturb the animal as little as possible. Tags on birds, for example, are limited to a certain percentage of the bird’s mass. But there are fewer guidelines for animals that aren’t birds, writes Julie van der Hoop, a graduate student in the MIT–Woods Hole Oceanographic Institute joint program. And much of the research on tag drag in marine mammals has been done with computer modeling, not actual animals.
Van der Hoop and her coauthors wanted to see how tags affect real, swimming dolphins. Working with Dolphin Quest Oahu, the researchers engineered a setup that would let them measure how tags changed dolphins’ energy use. Read More
Yes, fish. These aquarium lap-swimmers and pursuers of flaked food aren’t known for their joie de vivre. Yet in one hobbyist’s tanks, scientists say they’ve captured a rare instance of fish playing around.
James Murphy is a herpetologist at the Smithsonian National Zoological Park. Although he professionally studies reptiles and amphibians, he keeps fish as a hobby. It was one of his cichlids—a 5-inch fish of the species Tropheus duboisi—that first caught his attention by inventing a game. A weighted thermometer sat at the bottom of the fish’s tank, and the fish would repeatedly whack this thermometer with its head and let it bounce back. The behavior was hard to miss: the sound of the fish knocking the thermometer around could sometimes be heard from the next room.
Although examples of playful mammals are plentiful, such behaviors are harder to find in other groups of animals. Play examples in fish are especially controversial and difficult to come by, say Murphy and his coauthors, Gordon Burghardt and Vladimir Dinets of the University of Tennessee, Knoxville. To make sure that what they were seeing was really play, the authors checked it against a list of five criteria: Read More
Anyone who’s paged through a women’s magazine will recognize this strategy: to make a product seem better, surround it with a scientific glow. “Clinical trials show lashes grow up to 400% fuller!” “27% reduction of dark spots in 10 weeks!” “Ceramides!” Does this actually help convince people to hand over their cash? A study using promotions for fake drugs suggests that might be the case.
“Graphs equal truthiness,” says Aner Tal, a researcher at Cornell University’s Food and Brand Lab. “That’s actually where this research was born.” When giving academic presentations, he says, he’s always been encouraged to use more graphs, numbers, and figures to make his arguments convincing. If other academics are swayed by these scientific-looking additions, what about consumers? Read More
Maybe you gave your last realtor a long series of must-haves: a washing machine in unit, proximity to the train, a gas stovetop. But there’s no way you’re as picky as the driftwood hopper. This minute crustacean will only live in rotting chunks of driftwood.
David Wildish, a marine zoologist at Fisheries and Oceans Canada, is one of very few scientists who study tiny animals called talitrids. These crustaceans include sand hoppers (also known as sand fleas) along with ocean-living species. Within this family, the driftwood hoppers are simultaneously homebodies and world travelers.
“They feed there and breed there” inside decaying driftwood logs, Wildish says. Tucked in their homes, driftwood hoppers are safe from the shorebirds that prey on ordinary sand hoppers. Females store their fertilized eggs inside a body pouch until they hatch, like a less charming kangaroo. Read More
Did you know this week is International Cephalopod Awareness Days? I’ll assume your gifts are in the mail. Today is dedicated to squid, and you can’t have total cephalopod awareness without discussing fake squid testes. This post was first published in September 2013.
The best way to stay out of trouble, if you’re a shimmery, color-changing little squid, might be to paint on some pretend testes. Scientists have found that certain female squid can switch on and off a body pattern that makes them look male. They use a never-before-seen cell type to do it, and it may be all for the sake of keeping the actual testes owners far away.
The opalescent inshore squid, Doryteuthis opalescens, lives in the Eastern Pacific and is one of the main species caught for food in the United States. So you’d think someone would have noticed its trick before. But the animals shift their colors all the time, and no one seems to have paid much attention to a certain bright stripe particular to females. Read More
Sometimes scientists need to make their research subjects’ lives harder. No matter how much affection they may feel for those flatworms or fish or pigeons, there are certain things they can only learn by forcing the animals to use more energy. But for animals living in the wild, this can be tricky. Now scientists studying rodents in Eastern Europe say they’ve found a convenient way to do it: just give the animals a quick shave.
Paulina Szafrańska, at the Mammal Research Institute of the Polish Academy of Sciences, is interested in energy budgets. The energy animals get from food, she says, is like money to be spent on their daily activities: scurrying around, hunting, keeping their bodies warm, and so on. “When we make a hole in the budget” by increasing the cost of one of those activities, she says, the animal has to cut back somewhere else. “We call it [a] trade-off.” How it chooses to spend the balance of its energy budget shows scientists what’s most important to the animal. Does it kick some eggs out of the nest? Eat its young? Invest in its immune system?
To tweak the energy budget of birds, for example, scientists can clip their feathers and make flight more difficult. In the lab, they can give animals less food. But for wild mammals, there are fewer options.
Here’s where the shaving comes in. Read More
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
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