Like many new mothers, a female elephant seal puts herself on a strict diet after giving birth. She dives into the Pacific and spends two months eating everything she can find. It’s only by working hard at building up her blubber stores that she can get back her ideal body.
Northern elephant seals (Mirounga angustirostris) spend 9 to 10 months of the year at sea. Twice annually, the animals haul their enormous bodies ashore. In the winter, they gather on beaches in Mexico and Southern California for breeding and mating. Females deliver their pups and nurse them; males defend “harems” of dozens of mates and work on impregnating them again. While on land, the seals fast. Then they go back to the ocean, abandoning the babies to their own devices. In the spring, the seals return to the same beaches to molt, shedding their fur and even some skin before spending the rest of the year in the ocean.
During their travels, northern elephant seals may migrate as far as Alaska. They make dives almost half a mile deep, pursuing squid, fish, and other animals unfortunate enough to be in their paths. But to regain the body mass that they lost while fasting on land, they have to bank their calories. Energy that they save while swimming can be spent on longer dives. Energy gained from a stomach full of squid can be used to hunt some more.
Taiki Adachi, a graduate student in the polar science department at Tokyo’s Graduate University for Advanced Studies, wanted to learn how a migrating seal’s increasing blubberiness affects its swimming. Read More
If we’re lucky, this is behavior we haven’t seen since high school. The coolest individuals can’t stand to see others gaining social status, so they cut down any peers who are starting to elevate themselves. Ravens have to live with this behavior all the time. When the top-dog birds see others building new relationships, they attack these birds or put themselves in the middle. They may as well be spreading rumors or defacing each other’s lockers.
Wild ravens living in Austria were the ones to reveal this behavior to scientists. The ravens, a group of about 300 birds in the Austrian Alps, have discovered that a local zoo is a convenient source of food. So the wild birds hang around the captive animals year-round (they especially like the wild boar enclosure) and steal their provisions. Because of this, they’re used to seeing humans nearby.
For years, scientists have been capturing these birds, marking them with colored leg bands, and studying their social behavior. Now University of Vienna cognitive biologist Jorg Massen and his coauthors asked whether the most dominant birds might be sabotaging those lower down in the group.
The raven social ladder goes like this: Read More
The first time a colony of Antarctic penguins sees a towering human striding toward them, it must be like First Contact. They’ve never seen a species our size on land before, or anything that moves like we do. Even after penguins have interacted with researchers, the approach of a human is a physiologically stressful experience. To avoid stressing out their subjects so much, some researchers are experimenting with remote-control rovers. They’re hardly natural, but it turns out penguins don’t mind a motorized, four-wheeled intruder nearly as much as they mind us.
Stressing out penguins is bad for researchers, not just for birds. A panicked penguin can alter the data scientists are gathering, and may disturb its neighbors in the process. One way scientists are trying to bother animals less is by using tiny, under-the-skin transponders rather than the usual tags. These transponders are similar to the chip that a vet might implant in your dog. The only trouble is that the tag has to be read from close range: if you can’t hide a scanner where the animals are likely to walk past it, someone has to walk around and scan each bird like a box of cereal at the grocery store checkout.
Yvon Le Maho of the University of Strasbourg and his colleagues are trying to solve this problem with a rover. Read More
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