If you picture a woman twisting a doorknob, all the elements of this brief event show up in your mind – the woman, the twisting action of her hand and the doorknob. But as I describe this scene and as you read it, the players are mentioned in a very strict order. The subject (the woman) comes first followed by the verb (twisting), and the object (the doorknob) holds up the rear.
These word orders are one of the most fundamental aspects of any language and one of the earliest that young children pick up on. The Subject-Verb-Object order of English (SVO) is typical of many languages including French and Spanish. Other tongues like Japanese, Korean and Turkish use a different SOV order, where the object precedes the verb ( “woman doorknob twist”). Chinese uses both forms depending on the verb, and some scholars believed that it is returning to its roots as an SOV language, after a stint as an SVO one.
Now, a group of psychologists have discovered that the way that words are ordered in our languages has little effect on their sequence in our minds. Susan Goldin-Meadow from the University of Chicago found that people who are asked to describe events with only hand-gestures, they used the SOV order of Japanese and Turkish, regardless of the conventions of their mother tongue.
In the final months of 2001, five people died because they opened their mail. The killers were hidden inside the envelopes, small spores that were inhaled by the unfortunate addresses. Inside their bodies, the spores turned into the deadly bacteria, Bacillus anthracis – anthrax.
Anthrax has a long history in biological warfare but it made its debut as an agent of bioterror in 2001. The US anthrax postal attacks infected 22 people and claimed the lives of five. Since then, scientists have been feverishly studying the bacteria responsible in the hope that better understanding will lead to effective treatments. Two years ago, one group managed to develop a potential new treatment that neutralises anthrax toxins by acting on the host’s own cells rather than the bacteria itself.
For humans, sight is the most important of senses but only after we are born. Within the womb, surrounded by fluid, muscle and darkness, vision is of limited use and our eyes remain closed. But not all animals are similarly kept in the dark.
Cuttlefish develop inside eggs that are initially stained black with ink, but as the embryo grows and the egg swells, the outer layer slowly becomes transparent. By this time, the developing cuttlefish’s eyes are fully formed and we now know that even before they are born, they can use visual information from the outside world to shape their adult behaviour.
I’ve written two news stories in this week’s New Scientist. One is on the different tactics of four-year-old boys and girls as they compete for animal puppets. The other is on the webs spun by black widow spiders. The article on the venomous, evil, little critters is longer so I’m going to use this space to talk about the black widows instead…
Black widows are notorious for both the toxicity of their venom and the cannibalistic nature of their sex, but their webs are equally interesting and less well known.
The basic design – the “sheet-based” web – consists of a well-defined horizontal sheet of silk supported by some overhanging threads. Underneath the sheet, the spider spins “gum-footed threads” – vertical lines of silk with blobs of sticky glue at their base. These threads are incredibly taut and if an insect blunders into them, they break off from the ground, stick to the insect and catapult it into mid-air, where it struggles helplessly. The spider senses the vibrations through the sheet and goes in for the kill.
But Jacquelyn Zevenbergen at the University of Akron found that these webs are only used by hungry spiders. Over the course of a week, she fed several small Western black widows with daily crickets while starving an equal number of big ones. The result was a hundred or so spiders, all of the same size, but half of which were very hungry.
She found that the starving spiders mostly spun sheet-based webs, and did so twice as often as the sated spiders. They opted for a different design – the “tangle-based” web. As its name implies, this structure is a chaotic, three-dimensional network of non-stick strands. It’s a mess to behold – no distinctive sheet, no gumfooted threads, just a mass of silk with the spider in the middle.
If you listen to the egg of a crocodile, you can tell when it’s going to hatch by the small squeaks coming out of it. The squeaks come from the unborn babies and sound like “umph! umph! umph!”. These calls are common to all crocodilians and while zoologists have always suspected that they serve a specific purpose, until now, no one had ever tested this theory with an experiment.
Amelie Vergne and Nicoals Mathevon at the Universite Jean Monnet are the first to do so and they show that the youngsters call to tell their siblings that it’s time to hatch. And given that Nile crocodiles bury their eggs in sand, the calls also tell the mother that it’s time to dig her babies out.
In 1994, a third of the lions in the Serengeti were killed off by a massive epidemic of canine distemper virus (CDV), an often fatal infection that affects a wide range of carnivorous mammals. Seven years later, a similar epidemic slashed the lion population in the nearby Ngorongoro Crater. While CDV was undoubtedly involved, the scale of the deaths was unprecedented. What was it about the 1994 and 2001 epidemics that claimed so many lives?
Now, a team of scientific detectives led by Linda Munson from the University of California Davis, have solved the mystery. It turns out that the lions’ deaths were caused by a combination of viral infections, blood parasites and extreme climate changes. Heavy droughts had triggered a complex chain of events that left them riddled with an unusually high burden of parasites, a problem compounded by CDV infections, which depleted their immune system and left them vulnerable. It was a “perfect storm” of events that sealed their fate.
In 2004, the Australian Government turned a third of the Great Barrier Reef into the largest network of no-fishing zones in the world. All fishing was banned in an area of sea just smaller than England. It was a bold and controversial political move – jobs and livelihoods, it was said, were on the line. But the plan went ahead and in just a few years, there are signs that it’s working. One of the reef’s most heavily fished species – the coral trout- is enjoying a dramatic comeback, thanks to this most ambitious of marine conservation projects.
The vast expanse of the Great Barrier Reef is the largest living colony of animals on the planet and home to thousands of species. It has been part of a marine park since the 1970s but there were concerns that it wasn’t adequately protected. After all, most of the area was still open to destructive trawling vessels.
Due to mounting concerns, the Government launched a massive consultation involving scientists, policy-makers and local communities. The result was to turn 33% of the park into a network of no-take marine reserves, a massive increase from the tiny 5% that had previously been protected. The goal is simple – to prevent the continuing degradation of one of the world’s most important marine ecosystems, and to encourage diverse range of species to return to habitats in decline.
The world’s nations are stockpiling two drugs, Tamiflu and Relenza, to counter the threat of a bird flu pandemic. These drugs work by blocking a key protein that allows the virus to spread. But two years ago, a study revealed the structure of this protein and in doing so, shown that both Tamiflu and Relenza only work through a fortunate fluke.
The threat of bird flu is looming large in the minds of the public, scientists and politicians alike. So far, 241 people have died of the disease across 12 countries. But the real worry is that that the virus could mutate into a form that passes from person to person, triggering a worldwide pandemic similar to the 1918 outbreak that killed millions.
The pandemic threat has started a race to produce drugs that can quickly halt the progress of the virus in infected patients, reducing the chances of mutation and transmission. Two have been created – oseltamivir, better known as Tamiflu, and zanamivir, also known as Relenza. But worrying reports of resistance to these drugs are starting to emerge and there is a growing need for newer and better weapons. And as always, to find the ideal weapon, you must first know your enemy.
The differences between heterosexual and homosexual people are as much the subject of fascinating science as they are a source of social debate. And in many cases, the former can help to inform the latter. There is now plenty of research which shows that a person’s sexual orientation, far from being a phase or a lifestyle choice, is a reflection of fixed properties of their brain that develop at an early age.
A new study adds new weight to this evidence by using brain-scanning technology to look at the differences between the brains of gay and straight people. Ivanka Savic and Per Lindstrom at the Karolinska Institute in Stockholm scanned the brains of 90 men and women of different sexual orientations. Their images show that in the brains of gay people, certain features including symmetry and connections to the brain’s emotional centre are more closely matched to the brains of straight people from the opposite sex.
Using magnetic resonance imaging (MRI), Savic and Lindstrom showed that the brain’s two halves are almost exactly the same size in straight women and gay men. However, both straight men and lesbians had slightly asymmetrical brains, with the right hemisphere being 1-2% larger on the left. These differences only applied to the large cerebrum, which makes up most of our brains. The two halves of the cerebellum, which sits at the brain’s base, were symmetrical in all of the volunteers, regardless of sex or sexual preference.
Earlier studies have found similar results for patterns of brain activity. For example, parts of the brain involved in reward and emotion are more strongly activated when straight men and lesbian women look at female faces, and when straight women and gay men see male faces. The same patterns apply when people smell chemicals that probably act as human pheromones. But attractive faces and enticing pheromones are both related to sex, and responses to them could be learned over time.
But Savic’s and Lindstrom’s new study shows that these differences extend to fundamental aspects of the brain that aren’t directly linked to sex or behaviour, and that are probably fixed from birth.
In my last post, I wrote about how chimpanzees console one another to reduce the stress of violent confrontations. Conflict and competition are clearly important parts of chimp life and never more so than when sex is involved. The second study this week on the social lives of chimps demonstrates one of the strategies that female chimps use to avoid competition in some cases, and stir it up in others.
It comes down to sex calls – distinctive calls that female chimps make while mating. New research shows that they do this to advertise their availability to other males and garner both sperm and support. But the females use these sex calls strategically, and they keep things down when other females are around to avoid undue competition.
Chimpanzees are just one of a number of animals that make specific sex calls, but their reasons for doing so have been a mystery. To understand any animal communication, you need to work out who the audience is and until now, we didn’t know who was listening into the sex calls of chimps.