Fun lovin' crows
To any persistent observer, the intelligence and personality of crows are undeniable – as outlined in Adrian Barnett’s review of Gifts of the Crow (2 June, p 49). While it could be argued that such interpretations are subjective, the growing number of observations of crow behaviour surely carries some scientific weight.
As a hang-glider pilot, I sometimes share crows’ air and exuberance. If you fly near their nests, they will hang on the back of your sail, pecking furiously, and then fly to their mate with hunched shoulders and a nightclub bouncer’s attitude that says: “See love, I saw that big ugly guy off – I’m well hard.”
When the air is so rough that everything else is walking, I’ve often seen crows “surfing” around cliffs – repeatedly flying through the worst turbulence, just to get thrown around. It is obvious they do it for thrills, just as we go on theme park rides.
From Guy Cox
The mention of windsurfing crows reminded me of the one time I saw some of them “flying” backwards.
In the high plains of the Monaro, near the Snowy Mountains in Australia, I saw a line of crows sitting on a fence. It was blowing a gale, and each crow in turn would launch itself off and be blown backwards, dropping to the ground a few metres away.
They would then walk back and climb the fence for another go. They were obviously having fun.
Sydney, Australia
Lost in translation?
The presence of a modified component in messenger RNA (mRNA) – nucleotide base N6-methyladenosine – is an exciting and under-studied area (26 May, p 16). Your article on the work of Samie Jaffrey’s group at Cornell University in New York () gave the impression that this is a new discovery. It is not.
First reported in 1975, this modification has been found in mammals, insects, plants and yeast. Similarly, the identification of the human fat mass and obesity-associated protein as an enzyme that removes this modification from mRNA was also attributed to the Jaffrey group. In fact, this work was published six months earlier by a group led by Chuan He at the University of Chicago ().
My research has shown that most of the methylation occurs at the end of the message encoded in mRNA for translation to protein, and this was confirmed by Gideon Rechavi of Tel Aviv University in Israel and colleagues () a few weeks before the Jaffrey manuscript went online.
The editor writes:
• The earlier work mentioned was recognised by the Cornell researchers. The Jaffrey group, much like the Rechavi group, took things a step further, by showing mRNA methylation is not a rarity.
Deep danger
There may be another explanation for how ichthyosaurs – “dino dolphins” – suffered the bends other than rapid surfacing in the presence of predators (26 May, p 17). They would dive with one atmosphere of pressure in their lungs and when they surfaced, no matter how fast, they would have only one atmosphere of pressure, so could not suffer an air embolism in the way a rapidly surfacing scuba diver might.
However, at depth an ichthyosaur’s rib cage would be compressed, and nitrogen would go into solution. The deeper the dive and the longer, the greater the risk.
A more likely explanation for bone necrosis in more recent fossilised skeletal remains is that this animal evolved the ability to dive deeper and for longer, and would then get the bends with subsequent bone damage when resting near the surface at night.
Obese human divers are more susceptible to the bends, having more fat to absorb nitrogen. Maybe the ichthyosaur became a more successful feeder – being able to dive deeper – and became more vulnerable to the bends.
To love and cherish
Lasting love and the benefits of rearing progeny through a joint effort have developed over centuries of trial and error, and cannot be boiled down to the simple interactions of a few hormones, as proposed in “Engineering love” (12 May, p 28).
Some 70 years ago, my father lamented that it was too easy to get married and too difficult to get divorced. Since then, I have watched the system descend to the farce of people getting married underwater and then arranging effortless divorces.
The true purpose of marriage (of pairing) has been buried under the detritus of a society that, in general, seeks the desires of today and may the devil take tomorrow.
Irrational outcomes
In your editorial on a possible Greek exit from the eurozone, you wrote: “If the theorists are right, the eurozone was built on quicksand from the start” (26 May, p 3). The “if” is superfluous and no “theorists” are needed.
More interesting, from a scientific point of view, is why no serious scientific study has ever been made of the following questions: why do politicians invariably make irrational decisions? Why do we, their notional “masters”, tolerate it? What can we do about it?
Such paucity of intellect and seemingly addictive irrationality are bad enough in the current farce of the euro, but when they are brought to bear on serious matters such as climate change, the results could be devastating, not only for us, but for the generations to come.
Origins of flight
Further to Ian Flett’s letter on flying fish (19 May, p 32), in essence, they are very sophisticated flying machines, lacking only an airborne propulsion system. It is generally considered that tree-dwellers capable of true flight went through a stage of gliding, like flying squirrels.
Flying fish are already more capable than any arboreal glider. It may be only fish physiology – they are neither air breathers nor warm-blooded – that prevents them making the last step. The actual origin of birds may be uncertain, but flying fish are the best evidence that not just tree dwellers could have evolved flight.
It is apt that the same issue had an article on flying squid (p 39), which claimed they have progressed beyond gliding to airborne powered flight (although by jet rather than flapping).
Time flows by
The idea that the Yupno tribe of Papua New Guinea regard time as flowing uphill could be unwarranted (2 June, p 14).
When gesturing downriver, they’re probably just indicating water (or events) that have passed them (or happened) some time ago: the “past”. When pointing upriver, they’re probably just indicating water (or events) still to come: the “future”.
The same principle probably also applies when they are in their homes and cannot see the river. To be inside, they must have come through the door, so gesturing back towards the door simply indicates something that happened in the past, and gesturing in the opposite direction, away from the door, indicates the future.
Turing's ACE
Your Instant Expert (2 June) on the legacy of Alan Turing did not mention the Pilot ACE (Automatic Computing Engine) which has a strong claim to be regarded as the first high-speed, stored-program, Von Neumann-architecture digital computer.
It was based on Turing’s original design for a full ACE version and was built at the UK National Physical Laboratory from 1946. Pilot ACE was most notably used to analyse airframe structural stresses that caused the break-up of some early airliners.
Matter of debate
The idea of a group coming to a correct or better answer than an individual as a result of our innate argumentative nature has its merits (26 May, p 32). However, “groupthink” in the real world is often responsible for bizarre outcomes, in particular in politics.
Coupled with the suggestion that individual choice is driven not by what is sensible, but by what others might think of that choice, it would be interesting to hear of research into how we have managed to survive with such a flawed mechanism.
I fear the answer might be by the skin of our teeth.
Birth of democracy
You reported Richard Cincotta’s research, which shows that autocratic nations with a low median age are unlikely to secure democracy in the wake of revolution, such as the Arab spring (19 May, p 8).
Although birth rates had full coverage, a key contributor to understanding the data for ageing populations must also include survival rates of children.
It may be counterintuitive, but I predict Cincotta’s data would show that, as societies mature and the median age rises, child survival rates increase ahead of a drop in birth rates. After all, our instincts don’t stop at the need for sex and children; but for children who will outlive us.
I am moved to write because of the implications of the statistics. Numbers don’t lie, and if that is what they show, then slowing the birth rate in Africa and improving the odds for fledgling democracies there would depend on improving the survival rate of the children.
Quantum socks
You posed the question of how big an object can be and still show quantum properties (14 April, p 8). In my experience, it can be at least as big as a sock, as they seem to pop out of existence at random (check the number of odd ones in the sock drawer).
I have discovered they can be prevented from disappearing by entangling before exposing them to high temperatures in an aquatic environment.
For the record
• We got our moons in a muddle. In our story on possible liquid oceans on Neptune’s satellite Triton we used a picture of Saturn’s moon Titan (2 June, p 17).