SciTech Briefs

Wintering warblers sing during winter, practice for spring

Great reed warblers flee their European homelands during the colder months to winter in Sub-Saharan Africa. While there, the birds are reported to spend much of their time singing. For many bird species, singing is the method by which mates are selected. However, birds do not tend to mate during migratory seasons, so this frequent singing has perplexed researchers for some time.

Singing creates a 50 percent increase in energy consumption for the reed warbler compared to the birds’ resting state. In addition, it risks catching predator attention and cuts down on time that could be spent foraging. The dedication these birds give to their musical endeavors serves to show how important and vital the mating process is. They will go against efficient biological imperatives, such as preserving their energy and staying out of potential predators’ sights just to practice singing.

The warbler’s song consists of a composition made up of 40–60 possible sounds and has been described as “very harsh-sounding and creaking.” While initially expected to constitute a territory defense, the warblers’ winter song is now thought to be a rehearsal for the springtime, so that once mating season comes around, the warbler will be better prepared to woo potential mates.

Source: Science News

Babylonians utilized advanced math to chart moon, Jupiter

Ancient tablets recovered from Babylonian dig sites show that Babylonians using geometric methods to chart astronomical information more than 1,000 years before these methods were previously thought to be developed. Many Babylonian tablets are inscribed with calculations relating to the moon or the planets, but these are mostly based off of addition and other simple arithmetic.

Out of the hundreds of tablets, there were five which researchers took a more in-depth interest in. These tablets recorded what researchers call “trapezoid procedures,” named so because of the references to four-sided shapes with two parallel lines of differing sizes. The tablets were translated by Mathieu Ossendrijver, a historian of ancient science at the Humboldt University of Berlin, who determined that the fifth tablet contained nearly complete instructions for carrying out these trapezoid procedures.

The Babylonian astronomers were able to chart the change in Jupiter’s velocity over a 120-day interval using trapezoidal graphs. Similar methods were used in the 14th century by British and French scholars, but Ossendrijver says that the Babylonians pioneered those methods. These findings are just one of many mathematical histories which redefine our idea of past-era human intelligence.

Source: Science News

Different howling dialects between different species

The largest quantitative study of wolves’ howling patterns was able to define the ways in which wolf species howl. Some wolf species howl more than others, and researchers believe that this could represent an evolutionary thread in the development of our own speech patterns and use of language. This study was also the first of its kind to utilize machine learning techniques.

Researchers used computer algorithms to create an index of 21 different howl types, based on a sample of 2000 different howls. The large sample was analyzed based on factors such as pitch and fluctuation. Researchers found that the types of howls being uttered by different species, across a range from flat to highly modulated, were largely correlated to the species of wolf.

Wolf packs are a close social analogue for human social structures, and by understanding the communication patterns of these similar social structures, researchers will be able to “uncover evolutionary trajectories that led to more complex communications in the past, eventually leading to our own linguistic ability,” said Arik Kershenbaum, a research fellow in the Cambridge’s Department of Zoology and the study’s lead researcher. The evolution of communication is a burgeoning research field, bright with potential.

Source: Science Daily

Less apprehension, more reward shown in cocaine users

A novel study, published in Addiction Biology, contains evidence that cocaine users show signs of alternative brain functioning; compared to average people, cocaine users have lower-functioning inhibition pathways and higher functioning reward responses. In the study, cocaine users engaged in a gambling activity while brain measurements were simultaneously taken. Cocaine users showed hyperactivity in the ventral striatum, the brain’s “reward system,” whether they won or lost money.

This hypersensitivity was accompanied by a strange activation of the prefrontal cortex, a brain region heavily involved in higher-level decision-making and regulating behavior. One of the biggest roles of the prefrontal cortex is to inhibit impulsive behaviors, to which the reward pathway, the ventral striatum, responds well.

The results showed that cocaine users have a hyperactive reward pathway and a largely indifferent regulatory pathway, which means that cocaine users’ brains do not respond to the adverse effects of their behavior (e.g. losing money). This does not mean, however, that cocaine users are completely driven by reward stimulation and cannot make rational decisions; it simply means that they have higher susceptibility to addictive or pleasurable actions.

Source: Science Daily

Scientists stumped over the origin of unique human trait

Evolutionary arguments can explain many things, but chins are not among them. This question may seem strange or even irrelevant, but if you consider that humans are the only animals with chins, a great many questions begin to arise. “In some way, it seems trivial, but a reason why chins are so interesting is we’re the only ones who have them,” Nathan Holton, who studies craniofacial features and mechanics at the University of Iowa, said. “It’s unique to us.”

In fact, one of the ways by which archaeologists differentiate neanderthal skulls from those of modern humans is whether or not the skull has a chin. The “chin,” is a bony protrusion of the mandible, or the jawbone. One of the reasons chin-origin is interesting is that it “implies that there was some sort of behavioral or dietary shift between Neanderthals and anatomically modern humans that caused the chin to form,” said Zaneta Thayer, an anthropologist and biologist researcher from the University of Colorado, Denver.

One theory for why chins became necessary is that they help us chew food by dealing with the stresses of chewing. This explanation, however, is not robust, considering most of what we eat is cooked — not difficult to consume. Nobody can form a truly robust theory for the ori-chin of this uniquely human trait.

Source: The BBC

Unnatural selection causes man-made changes in species

Human activity may be affecting animal populations more than previously thought. Rather than simply eating our fellow creatures, researchers at the University of California Santa Cruz, led by Dr. Eric Palkovacs, are finding that “unnatural selection,” or the idea that human behavior rather than nature itself is causing adaptation within organisms, is becoming an increasingly prevalent phenomenon.

This new development in evolution is beginning to shape much of the wildlife we encounter on a daily basis. His research focuses on large fish and the ocean ecosystem: since larger fish are removed during fishing practices, the natural population has become smaller because the genes for largeness have been unnaturally “bred out.”

General examples of unnatural selection are commercial agricultural and hunting practices, which tend to favor the fatter, bigger, better specimens.
Another example is antibiotic treatments which impose an immense selection pressure on certain bacteria, providing massive benefits to those who can resist. Urbanization is also a massive environmental constraint we are placing on wildlife. Urban environments breed animals able to survive them.

Source: The BBC