When a gecko is desperately trying to escape from a predator, it has a creepy trick: It detaches its tail and leaves it wriggling on the ground to distract the hunter, while the rest of the lizard scampers off. Now, with high-speed video researchers have studied what happens to the left-behind tail, and they found that it flips and flops acrobatically, and changes direction and speed depending on what it bumps into. Researchers (and lizard-watching kids) already knew that the severed tail continues to move, but this study in the journal Biology Letters is the first to determine that the tail can independently respond to its environment.
Says lead researcher Anthony Russell: “The tail is buying the animal that shed it some time to get away.” … If the tail simply moved rhythmically back and forth, predators would quickly recognize a pattern and realize they’d been duped. Unpredictable tail movements keep predators occupied longer, and in some cases, they may even allow the tail itself to escape [Wired.com]. Russell notes that the leopard geckos he studied store fat in their tails, and suggests that if the tail can flop far enough away from the predator the gecko could return later to eat its own tail.
Yawning is so contagious that even chimpanzees who watched animations of cartoon chimps yawning couldn’t resist the impulse, according to a new study in Proceedings of the Royal Society B. Study coauthor Matthew Campbell doesn’t think the chimps were “fooled” by the animations into thinking they were looking at real chimps, he explained that there was evidence that chimpanzees “process animated faces the same way they process photographs of faces”. He said: “It’s not a real chimpanzee, but it kind of looks like a chimpanzee, and they’re responding to that” [BBC News].
The chimps were tested by first showing them animated chimps making a variety of facial expressions, and then another set of cartoons with yawning chimps. Only the latter cartoons elicited the yawning response. Campbell says the findings could assist in the future study of empathy…. “We’re interested in using animation for presenting stimuli to animals, because we can control all the features of what we show them” [BBC News].
As for why yawns are so contagious, Campbell suggests that the phenomenon may have evolved to allow some animals “to coordinate activity better, resting when other individuals are resting” in order that they “can travel when it’s time to travel, eat when it’s time to eat” [Discovery News].
Imitation may be the sincerest form of flattery not just for humans, but for many primates. In human social interactions, people have an instinctive tendency to copy each other’s body language and mannerisms, and previous studies have shown that such imitation gives rise to friendly feelings. Now a new study has found that capuchin monkeys respond to imitation in the same way, suggesting that the behavior may date back to early in our evolutionary history. The subtle aping may promote the formation of social groups—building cooperation, reducing conflict, and aiding the survival of each individual [Scientific American].
To study the behavior in capuchin monkeys, which live in highly social groups of 30 or 40 individuals, the researchers gave each monkey a Wiffle ball — a lightweight plastic ball with holes in it. Monkeys typically poked the ball with their fingers, put it in their mouths or used it to pound on something. Each monkey was paired up with two human researchers, one that copied their ball-handling skills, and one that did not. When the balls were put away, the monkeys appeared to prefer the company of the like-minded ball handler [Reuters].
Scientists have discovered a clever way the yellow-lipped sea krait snakes deter predators: By making it look as though the venomous snake has two heads, according to a study published in the journal Marine Ecology.
A biologist first noticed the snakes’ tricky method while diving in Indonesia. Researcher Arne Rasmussen observed the animals foraging for food while simultaneously moving what appeared to be a bobbing head around–but that bobbing body part was really its tail. “[T]he tail was slowly writhing back and forth, much in the same way as the head moves on a vigilant and actively searching snake” [National Geographic News], said co-author Johan Elmberg, who did not see the snake, but teamed up for the study with Rasmussen.
A quartet of clever rooks have provided evidence that one of Aesop’s fables could have a basis in fact. The tale in question tells the story of a thirsty crow. The bird comes across a pitcher with the water level too low for him to reach. The crow raises the water level by dropping stones into the pitcher. (Moral: Little by little does the trick, or in other retellings, necessity is the mother of invention) [AP]. In the new lab experiment, four rooks each dropped stones into a clear plastic tube, which raised the water level high enough to bring a floating worm within reach.
Rooks and crows are both in the corvid family, which researchers say rivals the great ape family for intelligence and tool use–the only other animal that has performed a comparable task was an orangutan, who spat into a tube to gain a floating peanut. Says study coauthor Nathan Emery: “We have performed a large number of studies on both corvids … and apes, and have found that the crow’s performance is on a par or often superior to apes. However, it is not particularly useful to say that one species is more or less intelligent than another because often the playing fields aren’t even” [The Independent].
Plenty of cat owners joke about being at the beck and call of a demanding feline, and now researchers have identified one vocal tactic that house cats use to manipulate their owners. The newly identified vocalization, called “solicitation purring,” has never been acknowledged or studied before, although cat fanciers, such as the study’s lead author Karen McComb, are quite familiar with it. “In the case of my cat, if he sees you stirring from sleep at all in the early morning he will immediately switch into giving this solicitation purring and position himself next to your head so you get the full impact” [Discovery News], she says.
Unlike the low-pitched purr that cats produce when they’re lazily lounging, this sound incorporates a high-pitched “cry” with a similar frequency to a human baby’s. The team said cats have “tapped into” a human bias – producing a sound that humans find very difficult to ignore [BBC News]. McComb suggests that cats may learn to embed the subtle wake-up call within the purring sound usually associated with contentment because more overt meowing is likely to get them kicked out of bed.
To get inside the head of a homing pigeon as it navigates towards its roost, researchers turned a flock of pigeons into cutting-edge techno-birds. The scientists outfitted the birds with “neurologgers” consisting of an electroencephalograph (EEG) to read the bird’s brain waves and a GPS tracker to record its location; by matching a bird’s position to its brain activity, the researchers could determine the bird’s reaction to the landscape below it. They found that, just like humans, the pigeons use visual landmarks in their navigation.
How homing pigeons find their way back to a starting point is not completely known. Studies have shown that the birds variously use the position of the Sun and the Earth’s magnetic field as a compass, and sense of smell and visual cues as navigation aids. But the use of visual cues has been difficult to study, because if a bird flies over a landmark and doesn’t change its course, it’s impossible to know whether the bird has not perceived the cue or is ignoring it [The New York Times].
A tiny fish common in European streams may learn in a more sophisticated way than has ever been recorded among animals and which mimics human learning. In a study published in the journal Behavioral Ecology, scientists found that the nine-spined stickleback fish used the success and failures of their peers to gauge where they should seek food.
The fish were shown to display a type of learning known as “hill-climbing,” in which an entity continually looks for a better solution to a problem; in this case, one fish copied others that were more successful in finding food. Researchers caught 270 nine-spined sticklebacks in Leicester, England. The fish were organized into experimental groups. These fish groups then took turns as either free swimmers in a tank with worm-yielding feeders at the end, or as “learners” in a transparent, partitioned-off area of the specially designed tank. One of the two feeders released more worms than the other [Discovery News].
The first group of free-swimming fish quickly learned which feeder was full of worms, and were then put into the observers’ chamber. Next, researchers switched which feeder held the worms, and the fish in the observation tank watched the next fish group identify the new worm-filled feeder. After switching the two groups of fish again, the original group made a beeline for the feeder full of worms that their peers had fed from.
It’s hard to imagine having more fun in the name of science: In a new study, researchers tickled young chimpanzees, bonobos, gorillas, orangutans, and even a few human babies, and recorded the vocalizations that resulted. Primatologist Marina Davila Ross wanted to examine the evolutionary history of laughter, so she and her colleagues recorded the sounds produced when they tickled 22 great apes and 3 human babies, picking the usual sensitive spots: armpits, palms, feet, and necks.
Scientists have known that great apes vocalize when tickled at least since Charles Darwin’s time. But it was unclear whether these sounds were actually related to human laughter. Now, researchers … have concluded that laughter has been evolving in primates over the last 10 to 16 million years, since at least the last common ancestor of humans and modern great apes [Wired.com].
When a banana is at stake, a low-status capuchin monkey may deceive the other monkeys in his troupe in order to get his hands on that tasty fruit. A new study of monkeys in an Argentinian national park found evidence that lowly monkeys give spurious alarm calls in order to scare off more dominant monkeys competing for food.
Tufted capuchin monkeys give a two-syllable “hiccup” call when they detect danger, like an approaching ocelot. Lead researcher Brandon Wheeler was studying a group of capuchins eating food left on platforms constructed in trees, when he noticed some of the monkeys made the calls when predators weren’t around. “They were giving the same calls that they give for cats extremely frequently,” he says. “When they do, other individuals often run out off the platform, which potentially leaves [the platform] available for whoever called to jump in to get some food” [ScienceNOW Daily News].
Four rooks by the names of Cook, Connelly, Fry, and Monroe have upped estimates of birds’ intelligence by mastering a series of challenges in which they had to use tools to get tasty worms. Researchers say that the birds’ skills rivalled those of well-known tool users such as chimpanzees and New Caledonian crows…. “The study shows the creativity and insight that rooks have when they solve problems,” [BBC News], says study coauthor Nathan Emery. Their abilities are all the more remarkable, researchers say, because rooks are not known to use tools in the wild.
In the laboratory tests, researchers devised a series of challenges in which the rooks had to figure out how to release food from glass tubes. The first featured a worm on a platform that would collapse, allowing it to be eaten if a stone were nudged into the tube. All four birds completed the task. They also chose stones of appropriate shape for tubes of differing sizes.The rooks were also quick to realise that long, thin stones would fit in every tube, regardless of its diameter, as long as it went in lengthways [The Times]. But picking up stones was a modest accomplishment compared to what came next.
If you get on a mockingbird’s enemy list, expect to be dive-bombed every time you come within the bird‘s sight. That’s one lesson that can be taken from a new study which proved that mockingbirds can recognize individual people, and attack those who have bothered their nests in the past. While ornithologists knew that certain highly intelligent birds like parrots and crows can recognize humans in a lab setting, they were surprised to find similar behavior in a songbird living in the wild. This paper is “a beauty,” says John Fitzpatrick, an ornithologist at Cornell University. “It’s amazing what a bird brain can do” [ScienceNOW Daily News].
The study was prompted by a series of bird attacks. A graduate student involved in research on bird nesting noticed that when she would make repeat visits to peoples’ yards the birds would alarm and attack her, while they would ignore people gardening or doing other things nearby…. Indeed, it seemed they could even recognize her car, and she had to start parking around the corner [AP]. So the researchers designed an experiment to investigate whether the birds really could identify an individual person.
Human females may get offended at dates who expect a little something extra after they buy a steak dinner, but for chimpanzees, the exchange may be a fair one [Reuters]. A new study of a chimp community living in the western African nation Côte d’Ivoire has found that males regularly share meat from their hunting expeditions with females, and get sex in return.
The researchers observed males sharing meat with females in estrus, who have sexual swellings that indicate their current fertility. More surprising was that males shared meat with females that didn’t have sexual swellings, perhaps in hopes of future success, the researchers say. The sex “may not necessarily occur immediately—it could occur sometime in the future,” said study co-author Cristina M. Gomes [National Geographic News]. The findings, she says, support the theory that chimps can engage in long-term planning, anticipating future events and remembering past interactions.
Young chickens just a few days old can count and perform basic arithmetic, according to a fluffy new study. Researchers manipulated objects that the chicks had formed an attachment to, moving the objects behind little screens, and found that the observant young birds kept track of where the objects were. In effect, the chicks were solving simple math problems like “4 – 2 = 2.”
While some adult animals, including primates and dogs, have been found to have an understanding of basic math, researchers had not previously demonstrated numerical abilities in any young animals (except for humans). Karen Wynn, who has reported evidence of numerical skills in human babies, points out that the chicks haven’t had a chance to learn or develop much. “This work, then, is a compelling existence proof that numerical understanding comprises a built-in system of unlearned knowledge,” Wynn says [Science News].
Human toddlers aren’t the only ones who throw tantrums to get their way, and human parents aren’t the only ones who give in, guiltily, to avoid causing a scene. Researchers have found that rhesus macaque monkeys engage in very similar behavior, in which baby monkeys pitch screaming fits until their mothers give in and feed them in order to prevent attacks from irritated onlookers. Explains lead researcher Stuart Semple: “The baby monkeys’ cries are high-pitched, grating and nasty to listen to – not just to their mother but to animals nearby. And we found that the way mothers respond to their crying infants is affected by who is around them at the time” [BBC News].
Researchers observed the behavior of wild monkeys on the island of Cayo Santiago, Puerto Rico. When a baby wanted to nurse but the mom wasn’t willing the shrieks started up, and researchers then monitored the actions of baby, mom, and any other monkeys within six feet. The researchers noted that during a temper tantrum the onlookers seemed bothered and on occasion made threatening gestures, or even chased, grabbed or bit the mother or the infant. Most of the aggression came from monkeys that weren’t close relatives and outranked mom in the social hierarchy. Her relatives proved more tolerant [Science News].
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
When a gecko is desperately trying to escape from a predator, it has a creepy trick: It detaches its tail and leaves it wriggling on the ground to distract the hunter, while the rest of the lizard scampers off. Now, with high-speed video researchers have studied what happens to the left-behind tail, and they found that it flips and flops acrobatically, and changes direction and speed depending on what it bumps into. Researchers (and lizard-watching kids) already knew that the severed tail continues to move, but this study in the journal Biology Letters is the first to determine that the tail can independently respond to its environment.
Yawning is so contagious that even 
Imitation may be the sincerest form of flattery not just for humans, but for many 
Scientists have discovered a clever way the yellow-lipped sea krait snakes deter predators: By making it look as though the venomous 
Plenty of cat owners joke about being at the beck and call of a demanding feline, and now researchers have identified one vocal tactic that house cats use to manipulate their owners. The newly identified vocalization, called “solicitation purring,” has never been acknowledged or studied before, although cat fanciers, such as the study’s lead author Karen McComb, are quite familiar with it. “In the case of my cat, if he sees you stirring from sleep at all in the early morning he will immediately switch into giving this solicitation purring and position himself next to your head so you get the full impact” [
To get inside the head of a homing pigeon as it navigates towards its roost, researchers turned a flock of pigeons into cutting-edge techno-birds. The scientists outfitted the 
A tiny 
It’s hard to imagine having more fun in the name of science: In a new study, researchers tickled young chimpanzees, bonobos, gorillas, orangutans, and even a few human babies, and recorded the vocalizations that resulted. Primatologist Marina Davila Ross wanted to examine the evolutionary history of laughter, so she and her colleagues recorded the sounds produced when they tickled 22 great 
When a banana is at stake, a low-status capuchin 
Four rooks by the names of Cook, Connelly, Fry, and Monroe have upped estimates of birds’ 
If you get on a mockingbird’s enemy list, expect to be dive-bombed every time you come within the 
Human females may get offended at dates who expect a little something extra after they buy a steak dinner, but for chimpanzees, the exchange may be a fair one [
Young chickens just a few days old can count and perform basic 
Human toddlers aren’t the only ones who throw tantrums to get their way, and human parents aren’t the only ones who give in, guiltily, to avoid causing a scene. Researchers have found that rhesus macaque 
