It’s hard for humans to tell what wild yaks are doing up there. Living high in the Tibetan Plateau, the rare ungulates are not easy to find. When scientists managed to track some down, they saw that females are hanging out in huge groups with no males allowed. And, though no one knows why, the females prefer habitat that’s higher and steeper than where the boys play.
Currently rebounding from poaching, wild yaks—which, male and female, look a bit like bison wearing skirts—are still endangered. Yet without knowing much about where or how yaks live, conservationists can’t be sure of the best ways to protect them. So University of Montana biologist Joel Berger and his colleagues traveled to Tibet in late 2012 and went looking for yaks. Read More
Subsisting on only one food is a poor survival strategy for humans, but a great one for caterpillars. Caterpillar species with very specialized diets are less likely to be plucked from their leaves by hungry birds, scientists have discovered. The less picky eaters are more apt to die (even if their moms praise them in the meantime). The finding is important not just for bugs and birds, but even for the health of the trees they inhabit.
Wesleyan University biologist Michael Singer and his colleagues tested a hypothesis that’s been around for a while: that among insects, more selective eaters are safer. Since these bugs spend all their time on one or a few host plants, the reasoning goes, they may be better adapted to hide on those plants. Insects that wander between many different plant species—with different colors and textures of leaves and branches—may be easier for predators to spot.
The researchers tested this by creating an experiment in the wild. In the forests of central Connecticut, they tied mesh bags around tree branches or small saplings. Read More
A word of advice to female fruit flies looking for a mate: it’s not hard to catch the eye of a male Drosophila. He’ll chase after almost anything that moves. Really—including a metal cube dabbed with pheromones. That may be embarrassing for the male, but it also shows scientists how a tiny-brained animal weighs information when making decisions.
“We call the robot ‘Flyatar,’” says University of Washington graduate student Sweta Agrawal, in reference to the movie Avatar. “It’s a device that allows us to essentially ‘become a fly’ so we can interact with other flies and understand what they’re doing.” Read More
1. Literally. Like pill bugs, Madagascar’s giant pill-millipedes protect themselves by rolling into a ball. The larger species may end up in a package the size of a tennis ball. But millipedes in the genus Sphaeromimus are a more manageable size, only up to an inch or two long.
2. It sings. Sphaeromimus millipedes have ridged music-making organs on their back ends. The male’s is called a “harp,” and the female’s is a “washboard.”
“Both sexes have a knob on the backside of the last leg pair which they rub across the ribs to produce sounds, like the [pick] of a guitar,” says Thomas Wesener, a curator at the Leibniz Institute for Animal Biodiversity in Bonn, Germany. He recently discovered seven new species of Sphaeromimus. Read More
Whoever named the macaroni penguin was not thinking of dinner, but the name is unfortunately apt. A shocking number of these birds get gobbled up by other large seabirds while they’re young, a new study found. Researchers are trying to fit this puzzle piece in with high predator numbers, rising ocean temperatures, and vanishing populations to see the whole picture of the macaroni penguin’s future.
Macaronis (Eudyptes chrysolophus), like other penguins, live in the southernmost parts of the planet. They’re not as much of a presence as they once were, though. A survey on South Georgia (a chilly, mostly empty island in the South Atlantic) found that breeding pairs of macaroni penguins dropped by more than 80% between the 1970s and early 2000s.
To find out where the birds are going, scientists tagged more than 2,000 penguins on South Georgia with transponders under their skin. “The technology is very similar to the microchips pet owners use to mark their cats and dogs,” says Catharine Horswill, a PhD student at the University of Glasgow and researcher with the British Antarctic Survey. Read More
In what might be considered a mixed message outside of the ichthyology world, scientists have named a new species of cavefish after the Indiana University Hoosiers. It’s blind, has its anus behind its head, and distinguishes itself from its nearest relative by being a little fatter. But its discovery might help keep the world’s other ugly cave dwellers alive, even those not named for sports teams.
Cavefish in the family Amblyopsidae live in dark corners of the eastern United States. There are about eight species, though it can be hard to tell them apart just by looking. Features that would normally be helpful are missing: they often have no eyes and no color to their bodies.
The genes of these unforthcoming fish, though, may tell stories that their bodies can’t. Read More
It’s a good thing human sex isn’t determined the same way a parasitoid wasp’s is, because “sugar and spice and everything nice” is much easier to rhyme than “sperm and moderate temperatures.” But that’s what little wasp girls are made of. A mother wasp can choose the sex of each egg she lays by deciding whether or not to fertilize it. Depending on the temperature of her environment, though, she may not get her way.
Whether you are biologically male or female isn’t really determined by spices, snips or snails, of course, but by the genes you receive from your parents. Outside of the mammal world, things get more interesting. In reptiles such as turtles or alligators, the sex of a developing egg may depend on the temperature of its nest. In certain insects, every fertilized egg becomes a female, while every unfertilized egg becomes a male (who has half the number of chromosomes as his sisters).*
This system of fertilized females and DNA-poor males shows up in bees, ants, and wasps, among other insects. But temperature could still matter—maybe one type of embryo is less likely to survive a cold snap, for example. Joffrey Moiroux, a biologist at the University of Montreal, wanted to tease apart these two different means of sex determination in a wasp species. It would require him scrutinizing every wiggle of a female wasp’s abdomen as she laid her eggs. Read More
If you’ve ever described your daily routine as leaving a comfortable place and going somewhere nearly incompatible with life, you were probably exaggerating how bad your job is. A Humboldt squid wouldn’t be exaggerating. It spends its days in areas of the ocean with what should be fatally low oxygen levels. To survive, it cranks down its metabolism. Scientists are now beginning to understand how it pulls off this trick, which is more impressive than fixing the office printer.
Dosidicus gigas, the Humboldt squid, is also called the “jumbo squid” for reasons that are obvious if you’re face-to-face with one. Individuals can be six feet long. They’re aggressive hunters that sometimes attack divers and can turn bright red when provoked. They reside in the Eastern Pacific, where they make a daily vertical commute: they spend nights hunting near the surface, and during the day they sink 300 meters or so.
The Humboldt squid’s range also overlaps closely with an area called an oxygen minimum zone, or OMZ. Here, thanks to quirks in the circulation of ocean waters, lower depths have almost no oxygen—as little as 5% of the amount near the surface. Read More
Watching an ostrich sprint across the plain like a mean two-legged dust mop, you might think a mistake has been made. Surely this isn’t one of evolution’s prouder moments? But new genetic evidence says that the group of birds including ostriches, emus, and other ungainly birds all came from flying ancestors. They lost the ability to fly not once, but over and over again. Something must have been working.
The ratites are a group of birds that includes the ostrich and emu, as well as the kiwi, rhea (like a smaller, South American ostrich), and cassowary (with a bright blue face and what looks like a toenail on its head). There were also the moa of New Zealand and the elephant bird of Madagascar—gigantic Big Bird types that went extinct within the past several hundred years, likely due to humans.
The birds themselves are pretty obvious, but the story of ratite evolution “has always been a contentious issue,” says Oliver Haddrath, an ornithology research technician and PhD student at the Royal Ontario Museum. Read More
It’s a good thing fish can’t operate a vehicle. Not only do drunk zebrafish swim extra fast, but they somehow get all the sober fish to follow them. Essentially, a drunk fish becomes the designated driver for the whole group.
Although a fish is only marginally like a human, fish can be convenient subjects for scientists who want to study the effects of alcohol. That’s because to get a fish tipsy, you don’t have to force it to drink anything. You only have to put a small concentration of alcohol into its tank.* Maurizio Porfiri, an associate professor at the New York University Polytechnic Institute of Engineering, used this technique to show last year that drunk zebrafish don’t fear robotic predators.
For his latest study of intoxicated fish, Porfiri and his coauthors had their subjects swim in three different alcohol concentrations: 0.25%, 0.5%, and 1%. The highest concentration translates to about a 0.1% blood alcohol content in the fish, Porfiri says—above the legal limit of .08% for people in the United States. Read More