{ Unsourced and old | Courtesy La Shampoo }

The secret behind the beautiful songs that birds sing has been decoded and reproduced for the first time.

One of the great challenges in neuroscience is to explain how collections of neural circuits produce the complex sequences of signals that result in behaviours such as animal communication, birdsong and human speech.

Among the best studied models in this area are birds such as zebra finches. These enthusiastic singers produce songs that consist of long but relatively simple sequences of syllables. These sequences have been well studied and their statistical properties calculated.

It turns out that these statistical properties can be accurately reproduced using a type of simulation called a Markov model in which each syllable is thought of as a state of the system and whose appearance in a song depends only on the statistical properties of the previous syllable. (…)

But other birds produce more complex songs and these are harder to explain. One of these is the Bengalese finch whose songs vary in seemingly unpredictable ways and cannot be explained a simple Markov model. Just how the Bengalese finch generates its song is a mystery.

Until now. (…) Instead of the simple one-to-one mapping between syllable and circuit that explains zebra finch song, they say that in Bengalese finches there is a many-to-one mapping, meaning that a given syllable can be produced by several neural circuits. That’s why the statistics are so much more complex, they say.

This type of model is called a hidden Markov model because the things that drives the observable part of the system–the song–remains hidden.

{ The Physics arXiv Blog | Continue reading }

related { New research suggests that our brains have a built-in bias against people whose accents don’t sound like our own }

{ Robin Schwartz }

Filing down horse teeth is a slobbery job. But Carl Mitz is grateful that he now has the undisputed legal right to do it.

This week, Mr. Mitz and three others won a three-year legal battle against the Texas Board of Veterinary Medical Examiners, which had sought to restrict the ancient craft of horse-teeth floating—an obscure job that involves filing a horse’s teeth to improve its bite—to licensed veterinarians. (…)

Texas, however, likely will continue to press the issue, meaning the victory could be fleeting. (…)

Horse-teeth floating is a lucrative job. Some practitioners say they can make $300,000 a year, and those who do it say it’s straightforward and requires no special training. But some veterinarians fear that unskilled floaters will damage the horse’s gums or strip away protective enamel.

{ Wall Street Journal | Continue reading }

photo { Audrey Corregan for Blend magazine, 2008 }

Undoubtedly you have heard that dogs can sense earthquakes before the tremors occur. While anecdotes are common, experimental evidence supporting these claims remains elusive. The USGS in the 1970′s even examined the ability of animals for prediction “but nothing concrete came out of these experiments.”

Cueing on changes in the weather is frequent among the animal kindgom. Indeed, the daily, seasonal, and annual cycles of animals are triggered to changes in temperature, day length, precipitation, among a host of other environmental cues. But predicting the weather changes including large catastrophic weather events such as cyclones and hurricanes may be of another ilk.

Being able sense an oncoming major hurricane or cyclone would prove an invaluable trait for animal. Storm surges can both decimate and rearrange marine habitats especially in coral reefs. (…)

In 2009, the typhoon Morakot passed over the Philippines, Taiwan and eventually mainland China. (…) Researchers counted sea snakes in the coastal area before (July), directly before (August 5-6, labelled during below), and after the typhoon (August 12-17th). (…)

Data suggests that snakes senses the approach of the typhoon even before it made landfall.

{ Deep-Sea News | Continue reading }

photo { Stuart Robertson Reynolds }

A team of engineers, physicists and mathematicians conducted a three and a half year study to find out exactly how cats manage to move the milk from saucer to mouth, while keeping their chins dry in the process.

And far from simply slurping at the bowl, researchers at MIT, Virginia Tech and Princeton University say the technique exhibits “a perfect balance between two physical forces.”

It was known from a 1941 study that when they lap milk, cats extend their tongues in a backwards ‘J’ – meaning the top of their tongue touches the surface first.

But recent high speed footage has shown that the top surface is the only part of the tongue to touch the liquid – meaning that unlike in dogs, where the tongue is fully immersed and used as a ladle, a more refined technique is at work.

The tip of the cat’s tongue scarcely brushes the liquid’s surface before it is rapidly drawn back. This forms a column of milk between the tongue and the surface, which the cat captures by closing its mouth.

This column is created by a balance between gravity pulling the liquid back to the bowl, and inertia – the tendency of a substance to move in a given direction until another force intervenes.

Cats instinctively know how to strike this balance in order to time the lapping and to capture the liquid in their mouths, according to journal Science.

{ Telegraph | Continue reading }

photo { Todd Fisher }

{ Corey Arnold }

{ Blue-faced golden snub-nosed monkeys }

A report issued this month found that nearly 1,000 tigers had been killed in the last decade as part of illegal trade. The numbers are based on tiger seizures from 11 of the 13 countries that still have wild tiger populations. That is 100 tigers a year falling victim to poachers. When estimates put the wild population at 3,500 individuals or less, loss of 100 a year to poachers is devastatingly high.

{ Promega Connections | Continue reading }

Tigers survive in 40% less area than they occupied a decade ago. (…)

Three tiger subspecies - the Bali, Javan, and Caspian - have become extinct in the past 70 years. The six remaining subspecies - Amur, Bengal, Indochinese, Malayan, South China, and Sumatran - live only in Asia, and all are threatened by poaching and habitat loss.

{ WWF | Continue reading }

{ 1. Steven Brahms | 2. Robert Davies }

Researchers create ‘lesbian’ mice by deleting a single gene.

Deletion of a single gene switches the sexual orientation of female mice, causing them to engage in sexual behaviour that is typical of males. Korean researchers found that deleting the appropriately named FucM gene causes masculinization of the mouse brain, so that female mice lacking the gene avoid the advances of males and try to mate with other females instead. The findings probably have little relavence to human sexual orientation, however.

{ ScienceBlogs/Neurophilosophy | Continue reading }

painting { Atilla Adorján }

We may think of scorpions as all bad ass, but scorpions still have to be careful. They have a painful sting, but some animals have evolved immunity to that. Even if they can drive off a predator with a sting, a scorpion close enough to sting its attacker is close enough to be damaged by its attacker.


In many cases, the best bet for a scorpion is to run away.

Temperature could play a big part whether scorpions get away from an attacker. Scorpions are ectotherms, so their performance is profoundly shaped by the external temperature. Daily temperatures can vary quite widely where scorpions live, particularly in desert regions.


Carlson and Rowe took a look at how temperature and drying affected bark scorpions (Centruroides vittatus). (…)

The authors did not test whether scorpions’ stinging behaviour was affected by drying them out. This is an odd omission, given that the title of this paper promising an examination of both temperature and drying on antipredator behaviours in general.

{ NeuroDojo | Continue reading }

{ Elena Dorfman | more }

{ Morad Bouchakour }

{ Physicists Discover Universal “Wet-Dog Shake” Rule | How fast should a wet dog rotate its body to dry its fur? Today we have an answer thanks to the pioneering work of physicists at the Georgia Institute of Technology in Atlanta. But more than that, their work generates an interesting new conundrum about the nature of shaken fur dynamics. | The Physics arXiv Blog | full story }

In fact, most of the life on the planet is probably composed of bacteria. They have been found making a living in Cretaceous-era sediments below the bottom of the ocean and in ice-covered Antarctic lakes, inside volcanoes, miles high in the atmosphere, teeming in the oceans — and within every other life-form on Earth.

These facts by themselves may trigger existential shock: People are partly made of pond scum. But beyond that psychic trauma, a new and astonishing vista unfolds. In a series of recent findings, researchers describe bacteria that communicate in sophisticated ways, take concerted action, influence human physiology, alter human thinking and work together to bioengineer the environment. These findings may foreshadow new medical procedures that encourage bacterial participation in human health. They clearly set out a new understanding of the way in which life has developed on Earth to date, and of the power microbes have to regulate both the global environment and the internal environment of the human beings they inhabit and influence so profoundly.

Science has determined that life arose and became complex through a process generally known as evolution, but biologists are engaged in an energetic debate about the form of that evolution. In essence, the argument centers on whether the biosphere should be characterized as a tree of life or an interactive web. In the tree construct, every living thing springs from a common ancestor, organisms evolve slowly by means of random mutations, and genes are passed on from parent to offspring (that is to say, vertically). The farther away from the common ancestor, generally speaking, the more complex the life-form, with humans at the apex of complexity.

The tree-of-life notion remains a reasonable fit for the eukaryotes, but emerging knowledge about bacteria suggests that the micro-biosphere is much more like a web, with information of all kinds, including genes, traveling in all directions simultaneously. Microbes also appear to take a much more active role in their own evolution than the so-called “higher” animals. (…)

Recent research has shown that gut microbes control or influence nutrient supply to the human host, the development of mature intestinal cells and blood vessels, the stimulation and maturation of the immune system, and blood levels of lipids such as cholesterol. They are, therefore, intimately involved in the bodily functions that tend to be out of kilter in modern society: metabolism, cardiovascular processes and defense against disease. Many researchers are coming to view such diseases as manifestations of imbalance in the ecology of the microbes inhabiting the human body. If further evidence bears this out, medicine is about to undergo a profound paradigm shift, and medical treatment could regularly involve kindness to microbes.

Still, in practice, the medical notion of friendly microbes has yet to extend much past the idea that eating yogurt is good for you. For most doctors and medical microbiologists, microbes are enemies in a permanent war. Medicine certainly has good reason to view microbes as dangerous, since the germ theory of disease and the subsequent development of antibiotics are two of medical science’s greatest accomplishments.

But there’s a problem: The paradigm isn’t working very well anymore. Not only are bacteria becoming antibiotic-resistant, but antibiotics are creating other problems. Approximately 25 percent of people treated with antibiotics for an infection develop diarrhea. Moreover, people who contract infections just by being hospitalized are at risk of developing chronic infections in the form of biofilms.

{ Miller-McCune | Continue reading | Thanks Constantine }

Understanding how ant colonies actually function means that we have to abandon explanations based on central control. This takes us into difficult and unfamiliar terrain. We are deeply attached to the idea that any system of interacting agents must be organized through hierarchy. Our metaphors for describing the behavior of such systems are permeated with notions of a chain of command. For example, we explain what our bodies do by talking about genes as “blueprints,” unvarying instructions passed from an architect to a builder. But we know that instructions from genes constantly change, as genes turn off and on in response to local interactions among cells.

Ant colonies, like genes, work without blueprints or programming. No ant understands what needs to be done or what its actions mean for the welfare of the colony. An ant colony has no teams of workers dedicated to fighting or foraging. Although it is still commonly believed that each ant is assigned a task for life, ant biologists now know that ants move from one task to another.

Colonies are regulated by networks of interaction. Ants respond only to their immediate surroundings and to their interactions with the other ants nearby. What matters is the rhythm of interactions, not their meaning. Ants respond to the pattern and rate of their encounters with each other, as well as to the smells they perceive in the world, such as the picnic sandwiches. (…)

A real ant colony is not a society of scheming, self-sacrificing individuals. It is more like an office that communicates by meaningless text messaging in which each worker’s task is determined by how many messages she just received. The colony has no central purpose. Each ant responds to the rate of her brief encounters with other ants and has no sense of the condition or the goals of the whole colony. Unlike the ants in Anthill, no ant really cares if the queen dies.

Ant colonies are not the only complex systems that function without central control. Brains, too, have no chain of command. (…) No one really knows how intelligence is distributed in the human brain. (…) The outstanding scientific questions about ants and brains are the same ones we have about many other biological systems that function without hierarchy, such as the immune system, the communities of bacteria in our bodies, and the patterns we see in the diversity of tropical forests. For all of these systems, we still don’t understand how the parts work together to produce the dynamics, the history, and the development of the whole system.

{ Boston Review | Continue reading }

Why do worms crawl on the sidewalk after it rains?

Worms do not drown when it rains … Worms of all kinds are highly susceptible to dessication [drying out]. They breed when it rains. They come out of the ground to find each other and to lie side by side in a mating posture, a difficult thing to do in the confines of their burrows. [And we complain about the back of a Ford!] The only time earthworms can safely come to the surface to breed is when the ground is thoroughly soaked … Worms don’t have lungs.

{ The Straight Dope | Continue reading }

artwork { Cy Twombly, Untitled, 1970 }