Posts tagged animal behavior
Articles and news from the latest research reports.
Are Crows Mind Readers … Or Just Stressed Out?
Are crows mind readers? Recent studies have suggested that the birds hide food because they think others will steal it — a complex intuition that has been seen in only a select few creatures. Some critics have suggested that the birds might simply be stressed out, but new research reveals that crows may be gifted after all.
Cracks first began forming in the crow mind-reading hypothesis last year. One member of a research team from the University of Groningen in the Netherlands spent 7 months in bird cognition expert Nicola Clayton’s University of Cambridge lab in the United Kingdom studying Western scrub jays, a member of the crow family that is often used for these studies. The Groningen team then developed a computer model in which "virtual jays" cached food under various conditions. In PLOS ONE, they argued that the model showed the jays’ might be moving their food—or recaching it—not because they were reading the minds of their competitors, but simply because of the stress of having another bird present (especially a more dominant one) and of losing food to thieves. The result contradicted previous work by Clayton’s group suggesting that crows might have a humanlike awareness of other creatures’ mental states—a cognitive ability known as theory of mind that has been claimed in dogs, chimps, and even rats.
In the new study, Clayton and her Cambridge graduate student James Thom decided to test the stress hypothesis. First, they replicated earlier work on scrub jays by letting the birds hide peanuts in trays of ground corn cobs—either unobserved or with another bird watching—and later giving them a chance to rebury them. As in previous studies, the jays recached a much higher proportion of the peanuts if another bird could see them: nearly twice as much as in private, the team reports online today in PLOS ONE.
Networking Ability a Family Trait in Monkeys
Two years of painstaking observation on the social interactions of a troop of free-ranging monkeys and an analysis of their family trees has found signs of natural selection affecting the behavior of the descendants.
Rhesus macaques who had large, strong networks tended to be descendants of similarly social macaques, according to a Duke University team of researchers. And their ability to recognize relationships and play nice with others also won them more reproductive success.
"If you are a more social monkey, then you’re going to have greater reproductive success, meaning your babies are more likely to survive their first year," said post-doctoral research fellow Lauren Brent, who led the study. "Natural selection appears to be favoring pro-social behavior."
The analysis, which appears in Nature Scientific Reports, combined sophisticated social network maps with 75 years of pedigree data and some genetic analysis.
Orangutans Have a Big Idea
Even when they are very young, orangutans may start to form ideas about their world—specifically, how and when to use certain tools. That’s the conclusion of a new study, which indicates that ape cultural traditions may not be that different from our own.
Like humans, orangutans have behavioral traditions that vary by region. Orangutans in one area use tools, for example, whereas others don’t. Take the island of Sumatra, in western Indonesia. By the age of 6 or 7, orangutans from swampy regions west of Sumatra’s Alas River use sticks to probe logs for honey. Yet researchers have never observed this “honey-dipping” among orangutans in coastal areas east of the water.
How do such differences arise? Many experts say that social learning is key—that the apes figure out how to honey-dip by watching others. But even the most careful field researcher can have difficulty proving this, says Yale University anthropologist David Watts. Wild apes are always responding to their environment, he says. And it may be influencing their behavior far more than social learning.
Social bee-haviour: The secret life of the hive
The extraordinary mental feats of bees are forcing us to rethink what we thought we knew about intelligence. Prepare to be surprised at what a tiny brain can do as we take a look at some of what these industrious honey-makers get up to.
Out of all the complex phenomena displayed in the behaviour of animal groups, many are thought to be emergent properties of rather simple decisions at the individual level. Some of these phenomena may also be explained by random processes only. Here we investigate to what extent the interaction dynamics of a population of wild house mice (Mus domesticus) in their natural environment can be explained by a simple stochastic model. We first introduce the notion of perceptual landscape, a novel tool used here to describe the utilisation of space by the mouse colony based on the sampling of individuals in discrete locations. We then implement the behavioural assumptions of the perceptual landscape in a multi-agent simulation to verify their accuracy in the reproduction of observed social patterns. We find that many high-level features – with the exception of territoriality – of our behavioural dataset can be accounted for at the population level through the use of this simplified representation. Our findings underline the potential importance of random factors in the apparent complexity of the mice’s social structure. These results resonate in the general context of adaptive behaviour versus elementary environmental interactions.
Seeing the world through the eyes of an Orangutan
Dr Neil Mennie, from The University of Nottingham Malaysia Campus (UNMC), has received funding from Ministry of Science and Technology and Innovation, Malaysia (MOSTI) to study the eye movements of Tsunami — a seven year old orangutan at The National Zoo of Malaysia (Zoo Negara). Not only will Dr Mennie’s research address vital questions about the visual cognition of humans and apes in natural tasks, it will also provide valuable enrichment for the juvenile captive-born orangutan.
Dr Mennie said: “Orangutans are particularly interesting because to survive in the treetops they must be very spatially aware of their surroundings. I hope to investigate their ability to search for food and to compare their progress with humans in 3D search and foraging tasks.
Dr Mennie, who is from the Cognitive and Sensory Systems Research Group in the School of Psychology at UNMC, is interested in how humans and apes use their brains to learn and make predictions about our surroundings. With the help of Tsunami’s keeper, Mohd Sharullizam Ramli, and the special eye tracking equipment that is worn over her head and shoulders, Dr Mennie has spent the last year recording Tsunami’s eye and body movements during the performance of complex actions such as locomotion, foraging for food and manipulation of small objects.
Insects change the way they communicate when drowned out by man-made noises
Birds and frogs do it, even whales have been known to do it. Now scientists have for the first time shown that insects also change the way they sing to one another when drowned out by man-made noises.
Click HERE to listen to a grasshopper battling traffic noise
Grasshoppers living next to a main road respond to the increased background volume of passing traffic by adjusting their summer courtship songs, scientists have discovered.
In order to make themselves heard above the low-rumble noise pollution of moving vehicles, male bow-winged grasshoppers of central Europe alter the pitch of their songs’ lower notes so that they rise to a mini-crescendo, the scientists found.
“Bow-winged grasshoppers produce songs that include low and high frequency components,” said Ulrike Lampe of the University of Bielefeld in Germany, who led the study published in the journal Functional Ecology.
“We found that grasshoppers from noisy habitats boost the volume of the lower-frequency part of their song, which makes sense since road noise can mask signals in this part of the frequency spectrum,” Dr Lampe said.
Bonobos Catch Yawns from Friends
For bonobos, yawning is contagious, but only between friends.
Yawns spread more easily between family and close friends, and from high-status monkeys to those lower on the totem pole, according to a study published online in the journal PLoS ONE. This pattern of social yawning mimics one found in humans and suggests infectious yawning is a byproduct of empathy, which coordinates emotions in a group.
"It underlines that the mechanism of yawn contagion in the two species is the same," said study co-author Elisabetta Palagi, a primate researcher at the University of Pisa in Italy. "One of the possible functions of yawn contagion is to synchronize individuals of a social group. In humans, yawn contagion is extremely important but just between people who share strong bonds."
Wrens Teach Eggs to Sing
Mothers usually set about teaching their offspring the moment they’re born. But the females of one Australian bird can’t wait that long.
Superb fairy-wren (Malurus cyaneus) mothers sing to their unhatched eggs to teach the embryo inside a ‘password’ — a single unique note — which the nestlings must later incorporate into their begging calls if they want to get fed.
The trick allows fairy-wren parents to distinguish between their own offspring and those of the two cuckoo species that frequently invade their nests. The female birds also teach their mates the password.
Fairy-wrens were known to discriminate against cuckoo nestlings on the basis of their foreign begging calls, says Sonia Kleindorfer, an animal behaviorist at Flinders University in Adelaide, who led the work. But it wasn’t known that wren nestlings learned the passwords before hatching.
“It has never been shown before that there is actually learning in the embryo stages,” says Kleindorfer. The finding, published today in Current Biology, has the potential to open up new lines of enquiry into prenatal learning in systems other than parasite-host relationships and in other animals — it could occur anywhere where it’s a benefit, she adds.
Birds of a feather don’t share a sick bed
House finches avoid sick members of their own species, say scientists, in a finding that could be useful for tracking the spread of diseases like bird flu that also affects humans.
Laboratory tests showed that the house finch, a particularly social North American species (Carpodacus mexicanus), was able to tell the difference between sick and healthy fellow birds and tended to avoid those that were unwell.
This was the first time that avoidance of sick individuals, already observed in lobsters and bullfrog tadpoles, has been shown in birds, according to a paper published in the journal Biology Letters.
"In addition, we found variation in the immune response of house finches, which means that they vary in their ability to fight off infections," says co-author Maxine Zylberberg of the California Academy of Sciences.
"As it turns out, individuals who have weaker immune responses and therefore are less able to fight off infections, are the ones who most avoid interacting with sick individuals."
This all meant that there were differences between individual birds’ susceptibility to disease, the time it would take them to recuperate and their likeliness to pass on the disease.
"These are key factors that help to determine if and when an infectious disease will spread through a group of birds," says Zylberg - and how quickly.