If homing pigeons wonder why humans are always driving them to faraway spots and leaving them behind, they don’t hold it against us. They just keep coming back, providing prize money for pigeon racers and new data for scientists studying the navigational powers of an avian brain. Now those scientists have discovered a new trick in pigeons’ homing toolkit: the birds learn best when traveling near a boundary.
A homing pigeon that’s looking for its loft can use many kinds of clues. It may navigate by the sun, the earth’s magnetic field, or the smell of a nearby chocolate factory. It might use visual landmarks, too. “The birds seem to return well to the spires in the center of Oxford,” for example, says Uppsala University mathematics researcher Richard Mann. However, Mann says, “What has been missing is a direct link from something we can measure about [any] landscape…to a measurable change in the birds’ navigational behavior.”
Countless biology students have dutifully learned to associate the Galapagos Islands with finches. Here Darwin noticed that birds on different islands had different beak shapes, and ta-da, theory of evolution. But galápago is Spanish for “tortoise,” and young Darwin also learned from watching these huge reptiles lumber across the archipelago. Today, the galápagos are only a fraction of their former population. And as they’ve disappeared, the landscape of the islands has transformed—because although Darwin didn’t know it, the tortoises were driving the evolution of an entire ecosystem.
The story starts before Darwin ever reached the Pacific island chain. So to get details from a time before naturalists were taking notes, Swansea University ecologist Cynthia Froyd and her colleagues searched a different set of records: fossilized tortoise poop.
In reality I can wave with only two arms, but don’t mistake my lack of appendages for indifference—I’m thrilled to be joining the Discover blog network today.
“Inkfish” is another name for cephalopods, the wily sea creatures that include octopuses, cuttlefish and squid. Inkfish is a science blog with its arms all over the place, from oceans to anthills and from prehistory to your doctor’s office. Occasionally it escapes from the tank and ends up someplace weird with a stomach full of aquarium fish.
I’ll be back here soon with new stories to share. In the meantime you can get to know Inkfish by browsing through my archives or checking out some of these favorite posts:
Many thanks to Discover for inviting me into a new undersea lair. Thanks also to longtime readers for helping me crawl here, and to new readers for joining us. I don’t know where we’ll go next but I can’t wait to see it.
Have you ever been asked to “please dislocate your left breast,” or if you “have noticed any hairs growing in places you normally wouldn’t have hairs”? Or maybe someone told you to “have a nice day” after your spouse just passed away or you’d received a cancer diagnosis. Not only do I hear things like this from time to time at my job, but I have grown to expect them.
I have been working for several months as a so-called standardized patient. The local medical school runs an excellent program that lets students conduct histories and physical exams in a simulated, standardized setting. This means I (and many others) pad around in rubberized socks and breezy hospital gowns and feign myriad diseases, syndromes, conditions, and (sometimes nasty) habits. It also means I overuse hand sanitizer and have many strangers listen to my heart, palpate my abdomen, and poke me with a broken wooden Q-tip to test my sensation. One time I even let someone stick their gloved hand in my mouth and squeeze my tongue a little.
Slave-making ants live all over, but scientists have so far found the new species in just three spots. In the early 2000s, the ants turned up in a state park in Vermont and a nature preserve in Rensselaerville, New York. In recent years, they’ve been found at Sleeping Bear Dunes National Lakeshore in Michigan.
For the most part, people move in and out of our lives at a trickle: a new coworker becomes a friend; a neighbor moves away. But there’s at least one cataclysmic monsoon in a young person’s social life, and that’s high school graduation. So long, hometown chumps! Hello, dorms! When scientists used cell phone records to track the social networks of people graduating from high school and starting the next phase of their lives, they saw a huge turnover in friends and acquaintances. Remarkably, though, the overall structure of each person’s network stayed the same.
“We wanted to see what happens to social networks when there is a big disruption,” says Jari Saramäki. A professor at Aalto University in Finland, he leads a research group studying complex networks.
In 2007, Saramäki and his coauthors gave cell phones to 24 soon-to-graduate high schoolers in a large city in the United Kingdom. The phones came with an 18-month contract and a guarantee that all their call data during that time would be collected by researchers. After graduating, a quarter of the subjects stayed in their home city and got jobs; the rest went off to universities nearby or in other cities.
For an easily crushed animal that rests during the day, a highway seems like maybe the worst possible home. Yet some bats pick roosts that are under bridges, or in other spots booming with human noise. Why subject themselves to that? For bats of at least one species, the sound of traffic is easy to doze through. And the more they hear it, the more they ignore it.
The greater mouse-eared bat, Myotis myotis, often turns up under bridges in Europe. Jinhong Luo, a PhD student at the Max Planck Institute for Ornithology, wanted to know how they can tolerate the noise. He and his colleagues trapped male bats from a cave in Bulgaria and brought them back to the laboratory for a hearing test, which was really a sleeping test.
Well, not sleeping exactly. Like many other bat species, the greater mouse-eared bat goes into “torpor” during the day, which is like a mini-hibernation. Its metabolism and body temperature drop sharply, letting the animal conserve energy. In the evening, the bats start to stir. After waking up gradually, they head out from their caves (or under-bridge roosts) to hunt.
Not so much a popularity contest as an altitude contest.
10: Himalayan Jumping Spider
The fuzzy and springy Euophrys omnisuperstes lives on the world’s highest mountains. It’s been found 6,700 meters (a little over four miles) high on Mount Everest. Some birds can fly at higher altitudes, but the spider lives there full-time, apparently subsisting on unlucky insects carried up to it by the wind.
9, 8: Iranian Space Monkeys
Twice this year, Iran announced that it had successfully sent a monkey on a sub-orbital rocket flight. The trips allegedly happened in January and December, both reaching heights of 120 kilometers (75 miles) before safely returning their rhesus macaque-nauts to Earth. But the Associated Press pointed out that the launches couldn’t be confirmed by outside sources, and that one post-launch photo showed an entirely different monkey than pre-launch.
Chances are you’ve never wondered how difficult it is to remove the testes of a hippopotamus. Other people have been thinking hard about it, though, because in fact it’s almost impossible.
Before sitting down to emasculate a common hippopotamus, Hippopotamus amphibius, it would be reasonable to ask why. They’re a threatened species, so usually conservationists try to make more baby hippos—not fewer. But in zoos, hippos turn out to be prolific baby-makers. Females can live for 40 years and may birth 25 calves in that time. This would be great news in the wild, but zookeepers don’t always have someplace to store a new two-ton animal.
Male hippos can also be aggressive toward each other, at least while they have all their man parts. For both of these reasons, zoos may want to have their male hippos fixed. But there are a few factors working against them, explains a new paper in the journal Theriogenology (that’s reproductive science for vets) by an international group of authors.
The first challenge is that hippopotamuses hide their genitals. The testes are inside the body, instead of outside in a scrotum. (Other mammals in the internal-testes club, since you asked, include the armadillo, sloth, whale, and platypus.) This makes the hippo’s testes totally invisible from the outside. Combined with a penis that the paper’s authors describe as “discreet,” it means it’s hard to tell males from females at a distance.
Even deadly predators crave a salad sometimes. Certain orb-weaver spiders—apparent full-time carnivores who eat by trapping prey, covering it with digestive juices, and then slurping it down like an insect smoothie—have been secretly taking their meals with a plant-based side dish. Namely, pollen.
Orb weavers are a family of spiders common all across the world; they’re the ones that weave the classic concentric-circle webs you see in picture books. Earlier studies have shown that those webs can collect a lot of pollen on their sticky strands, and that the spiders are willing to eat pollen in the lab. Benjamin Eggs, a graduate student at the University of Bern in Switzerland, and ecologist Dirk Sanders studied two kinds of orb weavers to see what truth there was to this rumor.