Rory Wilson recalls some nervous waterbirds.
“I’ve seen pelicans in Galapagos, in the port,” the Swansea University biologist says. One set of birds was standing by the fish-gutting area and waiting for scraps, while another group stood out of the fray in some nearby bushes. Although both sets of pelicans acted the same, a closer look at the birds waiting for fish scraps revealed that they were quaking slightly. The tips of their wings trembled.
Wilson thinks the tremor in the pelicans’ wings revealed their stress in that moment. He also believes that studying similarly small movements in all kinds of animals could give scientists new insights into their lives and health.
To show how this might work, Wilson and his colleagues put pocket-sized accelerometers on three very different animals: humans, elephants, and cockroaches. It’s popular for scientists to track animals’ large-scale movements—GPS devices and motion sensors have followed the migrations of birds and giant crabs and found the ideal fatness for elephant seals, for example. But Wilson wasn’t interested in where animals were going. Instead, he wanted to know how their small-scale movements revealed their emotions or other internal states.
For starters, the researchers compared two groups of humans. One group had used ecstasy (MDMA) in the past; the other had never taken the drug. Read More
It’s tough to be sperm. Your entire existence centers on one race that you will almost definitely lose. You don’t even get to take a warmup lap. Nevertheless, a glance at your competitors waiting at the starting line might give you some hints about who has an advantage. One factor that helps sperm win races is length—and not only for the reasons you might guess.
Long sperm generally have longer tails. This ought to make them faster and more powerful swimmers, which studies have confirmed. But what hasn’t been proven, write Clair Bennison and her colleagues at the University of Sheffield, is whether lankier sperm actually help a male win the race. Do long sperm fertilize more eggs?
In many animals, the sperm fighting for the finish line are not just competitors from one male, but from his rivals as well. The Sheffield scientists studied zebra finches (Taeniopygia guttata). Males of this species have widely varying sperm lengths, but each male is pretty consistent in the sperm he manufactures—making the birds ideal for the kind of race the researchers wanted to organize. Read More
Personality is written not just in the genes, but in the egg yolk. It can even come from the kind of relationship that exists between an animal’s parents. Researchers found new evidence for this when they played matchmaker for several dozen quail. Even though the eggs were taken from their parents before hatching, bird couples in committed relationships had chicks with markedly different behaviors than couples who only dated.
It’s not hard to forge a bond between Japanese quail (Coturnix japonica). In nature, the birds pair off into monogamous couples while they’re mating and laying eggs. These relationships last for five or six weeks. During that time, mates stay side-by-side, and call out and search for each other if they’re separated.
Behavioral researcher Océane Le Bot and her colleagues at the University of Rennes in France recreated these relationships using 60 quail, which they’d gotten from a farm where the birds were being raised as broilers. Read More
You may be physically fit right now, but if you spent all winter snoozing and starving, you’d emerge looking a lot more “pool noodle” than “beach body.” Yet mammals that hibernate don’t have that problem. Rather than stumbling out of their dens on atrophied legs, they hop right into hunting for food and dodging predators.
How they manage this is a secret they guard in their chilly burrows. Some ground squirrels may have given away a clue, though. Scientists found that their bodies start building new muscle in late winter—well before they leave hibernation.
“It was hard to believe,” says Allyson Hindle, who did the research at the University of Colorado (she’s now at Massachusetts General Hospital).
She and her coauthors studied the thirteen-lined ground squirrel, Ictidomys tridecemlineatus, a little North American rodent with snazzy stripes. Read More
If ever there was a scientific study that deserved to be a children’s picture book, this was it. Scientists belly-crawled through the forests of the Ozarks, flipping stones and looking for slimy things that wriggled away from them. They learned that the forest is secretly packed with salamanders in unfathomable numbers, as many as 10 times what earlier researchers had thought. The amphibians emerged as the hidden heroes of the woodland ecosystem.
Let’s imagine it.
On the cover, an illustration of heaps of salamanders. They’re multicolored and represent many species.
The opening pages are an introduction to salamanders. Maybe one salamander in particular. Sally is too obvious, so let’s say Solomon Salamander. Read More
Think you’re in control of your own body? A simple virtual-reality session could not only make you feel like an avatar’s body is your own, but make you speak more like the digital character.
First there was the rubber-hand illusion, a classic experiment that showed syncing up someone’s touch perceptions with what they see happening to a rubber hand can make them feel strongly that the fake body part is their own. Since its publication in 1998, this study has inspired all kinds of spinoffs. Some involve entire “rubber” bodies—researchers have swapped people into the bodies of giants and Barbies, and used virtual reality to make them feel child-sized. By playing the sound of a hammer hitting marble while they lightly tapped subjects’ own hands, scientists have even made people feel like their hands are made of stone.
Mel Slater, a researcher at the University of Barcelona, has been studying these illusions at his computer-science-meets-neuroscience lab. This time you might say he was interested in a rubber voice. Read More
Even kings and queens that have six legs and live underground aren’t immune to royal machinations. In one Asian termite species, queens choose to shut their mates out of the picture when it’s time to breed a successor. They simply clone themselves to make new queens. To keep the king’s genes away, the queen makes special eggs that have no entrances for sperm—all their drawbridges are pulled up tight.
The lives of Reticulitermes speratus termites are worthy of an HBO series. The story starts when a new colony is founded by a single termite pair, the king and queen. They mate in the usual way and fill the colony with workers, their offspring. No one reproduces except for the royal pair. Everyone in this humble kingdom of dirt knows their places.
The queen can live for more than 11 years, and as she ages, the order of things starts to get muddy. Read More
If you were assigned to watch a dozen dwarf mongooses on the savannah, would you know how to keep them safe? Or would half of them get snatched by snakes before you finished checking the dictionary to make sure they weren’t really a dozen mongeese? Luckily these animals don’t need us to watch their backs. Volunteers within their ranks take turns watching out for predators, and they know how to monitor a range of risk factors while doing their jobs.
Dwarf mongooses (Helogale parvula) are squirrel-sized carnivores in East and Central Africa. They live and breed in social groups, with lower-ranking animals helping to raise a dominant pair’s young. While they’re out in the open, some members will spontaneously go on “sentinel” duty. They’ll stop what they’re doing, find higher ground (a tree branch, the top of a termite mound), and spend a few minutes watching for predators. If they see anything, the mongooses have different alarm calls to tell the group what type of danger approaches.
Sentinels are crucial for dwarf mongooses because they mostly eat bugs, and it’s hard to keep an eye out for predators while you’ve got your face in the dirt. Dwarf mongooses have plenty of predators, too, say University of Bristol graduate student Julie Kern and behavioral ecologist Andrew Radford. At the scientists’ study site in South Africa, the little mammals are vulnerable to wildcats, jackals, civets, servals, honey badgers, larger mongooses, monitor lizards, five kinds of snake, and fourteen birds of prey. (Still want to babysit?) Read More
What—just because they’re called gut microbes, you’ve been keeping them in your colon? How unoriginal.
This is Bankia setacea, also called the Northwest or feathery shipworm. Humans usually pay attention to shipworms only when they perform their namesake activity: burrowing face-first into our boats or docks and eating their way through. Shipworms are bivalves, like clams or scallops, but their shells are shrunken into a set of rasping tools at each worm’s front end.
Animals that subsist on wood usually need help. Studies of termite guts, as well as wood-eating fish and beetles, have found specialized bacteria that break down the tough plant materials the animals themselves can’t. Even humans and other omnivores and carnivores get a digestive hand from microbes. The abundant bugs in our intestines play a role in breaking down our food and getting the nutrients out.
Yet the digestive tract of Bankia setacea is weirdly empty. Read More
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