Author Archives: Attention to the Unseen

In defence of bats: Beautifully designed mammals that should be left in peace

By Daniel Horton, University of Surrey

As a wildlife veterinarian, I often get asked about bats. I like bats, and I am always eager to talk about how interesting they are. Unfortunately the question is often not about biology but instead “what should I do about the ones in my roof?”.

With some unique talents and remarkable sex lives, bats are actually one of the most interesting, diverse and misunderstood groups of animals. Contrary to popular belief, they are beautiful creatures. Not necessarily in the cuddly, human-like sense – although some fruit bats with doey brown eyes and button noses could be considered so – but they are beautifully designed.

This couldn’t be illustrated better than by the discovery of the oldest known complete bat fossil, more than 53 million-years-old yet with a similar wing design to those flying around today. To put it in perspective, 50m years ago our ancestors were still swinging from the trees and would certainly not be recognised as human. But even then bats already had the combination of thin, long forearms and fingers covered by an extremely thin, strong membrane, which allowed them to master the art of powered, agile flight.

A flying fox shows off its 50 million-year-old wing design.
Duncan PJ, CC BY-SA

Soon afterwards, fossils record another game-changing adaptation in the evolution of most bats, and that is the ability to accurately locate prey using sound (what we call echolocation). These two adaptations early in their history gave bats an evolutionary edge compared to some other mammals, and allowed them to diversify into almost all habitats, on every continent except Antarctica.

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How a child’s cells become scattered throughout its mother’s body

Carl Zimmer writes: Recently a team of pathologists at Leiden University Medical Center in the Netherlands carried out an experiment that might seem doomed to failure.

They collected tissue from 26 women who had died during or just after pregnancy. All of them had been carrying sons. The pathologists then stained the samples to check for Y chromosomes.

Essentially, the scientists were looking for male cells in female bodies. And their search was stunningly successful.

As reported last month in the journal Molecular Human Reproduction, the researchers found cells with Y-chromosomes in every tissue sample they examined. These male cells were certainly uncommon — at their most abundant, they only made up about 1 in every 1,000 cells. But male cells were present in every organ that the scientists studied: brains, hearts, kidneys and others.

In the 1990s, scientists found the first clues that cells from both sons and daughters can escape from the uterus and spread through a mother’s body. They dubbed the phenomenon fetal microchimerism, after the chimera, a monster from Greek mythology that was part lion, goat and dragon.

But fetal cells don’t just drift passively. Studies of female mice show that fetal cells that end up in their hearts develop into cardiac tissue. “They’re becoming beating heart cells,” said Dr. J. Lee Nelson, an expert on microchimerism at the Fred Hutchinson Cancer Research Center in Seattle.

The new study suggests that women almost always acquire fetal cells each time they get pregnant. They have been detected as early as seven weeks into a pregnancy. In later years, the cells may disappear from their bodies, but sometimes the cells settle in for a lifetime. [Continue reading…]

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Guns, germs, and steal

We have all been raised to believe that civilization is, in large part, sustained by law and order. Without complex social institutions and some form of governance, we would be at the mercy of the law of the jungle — so the argument goes.

But there is a basic flaw in this Hobbesian view of a collective human need to tame the savagery in our nature.

For human beings to be vulnerable to the selfish drives of those around them, they generally need to possess things that are worth stealing. For things to be worth stealing, they must have durable value. People who own nothing, have little need to worry about thieves.

While Jared Diamond has argued that civilization arose in regions where agrarian societies could accumulate food surpluses, new research suggests that the value of cereal crops did not derive simply from the fact that the could be stored, but rather from the fact that having been stored they could subsequently be stolen or confiscated.

Joram Mayshar, Omer Moav, Zvika Neeman, and Luigi Pascali write: In a recent paper (Mayshar et al. 2015), we contend that fiscal capacity and viable state institutions are conditioned to a major extent by geography. Thus, like Diamond, we argue that geography matters a great deal. But in contrast to Diamond, and against conventional opinion, we contend that it is not high farming productivity and the availability of food surplus that accounts for the economic success of Eurasia.

  • We propose an alternative mechanism by which environmental factors imply the appropriability of crops and thereby the emergence of complex social institutions.

To understand why surplus is neither necessary nor sufficient for the emergence of hierarchy, consider a hypothetical community of farmers who cultivate cassava (a major source of calories in sub-Saharan Africa, and the main crop cultivated in Nigeria), and assume that the annual output is well above subsistence. Cassava is a perennial root that is highly perishable upon harvest. Since this crop rots shortly after harvest, it isn’t stored and it is thus difficult to steal or confiscate. As a result, the assumed available surplus would not facilitate the emergence of a non-food producing elite, and may be expected to lead to a population increase.

Consider now another hypothetical farming community that grows a cereal grain – such as wheat, rice or maize – yet with an annual produce that just meets each family’s subsistence needs, without any surplus. Since the grain has to be harvested within a short period and then stored until the next harvest, a visiting robber or tax collector could readily confiscate part of the stored produce. Such ongoing confiscation may be expected to lead to a downward adjustment in population density, but it will nevertheless facilitate the emergence of non-producing elite, even though there was no surplus.

This simple scenario shows that surplus isn’t a precondition for taxation. It also illustrates our alternative theory that the transition to agriculture enabled hierarchy to emerge only where the cultivated crops were vulnerable to appropriation.

  • In particular, we contend that the Neolithic emergence of fiscal capacity and hierarchy was conditioned on the cultivation of appropriable cereals as the staple crops, in contrast to less appropriable staples such as roots and tubers.

According to this theory, complex hierarchy did not emerge among hunter-gatherers because hunter-gatherers essentially live from hand-to-mouth, with little that can be expropriated from them to feed a would-be elite. [Continue reading…]

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How music can help relieve chronic pain

By Don Knox, Glasgow Caledonian University

As the 17th-century English playwright William Congreve said: “Music has charms to soothe a savage breast.” It is known that listening to music can significantly enhance our health and general feelings of well-being.

An important and growing area of research concerns how music helps to mitigate pain and its negative effects. Music has been shown to reduce anxiety, fear, depression, pain-related distress and blood pressure. It has been found to lower pain-intensity levels and reduce the opioid requirements of patients with post-operative pain.

Music has helped children undergoing numerous medical and dental procedures. And it has been demonstrated to work in a variety of other clinical settings such as palliative care, paediatrics, surgery and anaesthesia.

So what makes music so effective at making us feel better? The research has often drawn on theories around how nerve impulses in the central nervous system are affected by our thought processes and emotions. Anything that distracts us from pain may reduce the extent to which we focus on it, and music may be particularly powerful in this regard. The beauty is that once we understand how music relates to pain, we have the potential to treat ourselves.

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The inside story behind the discovery of a new species of ancient human

Ed Yong writes: Lee Berger put his ad up on Facebook on October 7th, 2013. He needed diggers for an exciting expedition. They had to have experience in palaeontology or archaeology, and they had to be willing to drop everything and fly to South Africa within the month. “The catch is this—the person must be skinny and preferably small,” he wrote. “They must not be claustrophobic, they must be fit, they should have some caving experience, climbing experience would be a bonus.”

“I thought maybe there were three or four people in the world who would fit that criteria,” Berger recalls. “Within a few days, I had 60 applicants, all qualified. I picked six.” They were all women and all skinny — fortunately so, given what happened next. Berger, a palaeoanthropologist at the University of the Witwatersrand, sent them into the Rising Star Cave, and asked them to squeeze themselves through a long vertical chute, which narrowed to a gap just 18 centimeters wide.

That gap was all that separated them from the bones a new species of ancient human, or hominin, which the team named Homo naledi after a local word for “star.” We don’t know when it lived, or how it was related to us. But we do know that it was a creature with a baffling mosaic of features, some of which were remarkably similar to modern humans, and others of which were more ape-like in character.

This we know because the six women who entered the cave excavated one of the richest collections of hominin fossils ever discovered — some 1,550 fossil fragments, belonging to at least 15 individual skeletons. To find one complete skeleton of a new hominin would be hitting the paleoanthropological jackpot. To find 15, and perhaps more, is like nuking the jackpot from orbit. [Continue reading…]

See also the research article announcing the discovery: Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa.

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The Amazon tribe protecting the forest with bows, arrows, GPS and camera traps

The Guardian reports: With bows, arrows, GPS trackers and camera traps, an indigenous community in northern Brazil is fighting to achieve what the government has long failed to do: halt illegal logging in their corner of the Amazon.

The Ka’apor – a tribe of about 2,200 people in Maranhão state – have organised a militia of “forest guardians” who follow a strategy of nature conservation through aggressive confrontation.

Logging trucks and tractors that encroach upon their territory – the 530,000-hectare Alto Turiaçu Indigenous Land – are intercepted and burned. Drivers and chainsaw operators are warned never to return. Those that fail to heed the advice are stripped and beaten.

It is dangerous work. Since the tribe decided to manage their own protection in 2011, they say the theft of timber has been reduced, but four Ka’apor have been murdered and more than a dozen others have received death threats. [Continue reading…]

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Is there anything wrong with men who cry?

Sandra Newman writes: One of our most firmly entrenched ideas of masculinity is that men don’t cry. Although he might shed a discreet tear at a funeral, and it’s acceptable for him to well up when he slams his fingers in a car door, a real man is expected to quickly regain control. Sobbing openly is strictly for girls.

This isn’t just a social expectation; it’s a scientific fact. All the research to date finds that women cry significantly more than men. A meta-study by the German Society of Ophthalmology in 2009 found that women weep, on average, five times as often, and almost twice as long per episode. The discrepancy is such a commonplace, we tend to assume it’s biologically hard-wired; that, whether you like it or not, this is one gender difference that isn’t going away.

But actually, the gender gap in crying seems to be a recent development. Historical and literary evidence suggests that, in the past, not only did men cry in public, but no one saw it as feminine or shameful. In fact, male weeping was regarded as normal in almost every part of the world for most of recorded history. [Continue reading…]

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The dangerous idea that life is a story

Galen Strawson writes: ‘Each of us constructs and lives a “narrative”,’ wrote the British neurologist Oliver Sacks, ‘this narrative is us’. Likewise the American cognitive psychologist Jerome Bruner: ‘Self is a perpetually rewritten story.’ And: ‘In the end, we become the autobiographical narratives by which we “tell about” our lives.’ Or a fellow American psychologist, Dan P McAdams: ‘We are all storytellers, and we are the stories we tell.’ And here’s the American moral philosopher J David Velleman: ‘We invent ourselves… but we really are the characters we invent.’ And, for good measure, another American philosopher, Daniel Dennett: ‘we are all virtuoso novelists, who find ourselves engaged in all sorts of behaviour… and we always put the best “faces” on it we can. We try to make all of our material cohere into a single good story. And that story is our autobiography. The chief fictional character at the centre of that autobiography is one’s self.’

So say the narrativists. We story ourselves and we are our stories. There’s a remarkably robust consensus about this claim, not only in the humanities but also in psychotherapy. It’s standardly linked with the idea that self-narration is a good thing, necessary for a full human life.

I think it’s false – false that everyone stories themselves, and false that it’s always a good thing. These are not universal human truths – even when we confine our attention to human beings who count as psychologically normal, as I will here. They’re not universal human truths even if they’re true of some people, or even many, or most. The narrativists are, at best, generalising from their own case, in an all-too-human way. At best: I doubt that what they say is an accurate description even of themselves. [Continue reading…]

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