Editor's pick: Bat-eating crocodiles have been seen before
You report “weird orange crocodiles” found gorging on bats in caves in Gabon (15 October, p 16). In the 1980s I worked with Partridge Films on a documentary for the BBC called Stolen River, about the drying-up of the Savuti river in Chobe National Park, Botswana, due to a tectonic shift. The crocodiles and hippos died out totally and the rest of the game migrated to the Linyanti river system.
Out looking for shooting locations, I climbed a nearby hill late one afternoon. I sat down to watch the sunset and looked around. I could not believe what I saw: a crocodile sunning itself on a ledge outside a small cave.
At dusk, bats started flying out. The crocodile snapped them out of the air. The following evening and dawn we set up and filmed it. A few weeks later, after we got the film rushes back from the lab, we decided to shoot some more. We set up a camera with a motion sensor one afternoon and retrieved it the next day. Imagine our surprise when we got the film back to see a leopard ambush and kill the crocodile.
A volcanic impact in the English countryside
Recently I was given a copy of 快猫短视频 in which a photo of the Laki fissure in Iceland caught my attention (23 January, p 25). The fissure is the remnant of a massive volcanic event between 1783 and 1784.
Many years ago I surveyed a farm in Cheshire that was due for demolition. I found that the farm buildings had undergone drastic changes around 1790 that would have reduced the farm's output. At the time I assumed that they were due to local economic conditions.
Now I find reports that the Laki eruption caused long-lasting hardship for rural workers in England. May the changes I observed have been linked to this? Do other readers know of similar changes to farm buildings in England in this period?
First class post
Whoever you root for in politics, reality will always be the winner
Stig Soldal RØnning has words of reassurance for those trapped in a post-fact world (30 November, p 29)
Some of our readers' favourite inventions
I, probably along with many others, was staggered to find no mention of the laser in your list of 60 years of innovations (19 November, p 30). It has revolutionised metrology, manufacturing, data storage, entertainment, printing, communication – one could go on. Surely it's a most influential and pervasive technology?
Some of our readers' favourite inventions
I take issue with John Agar when he says that the mobile phone is “a rare case of a technology that is so important that we carry it everywhere”. He seems to forget the wrist watch. Personally, I carry my hearing aids everywhere.
Some of our readers' favourite inventions
Celebrating your 60th anniversary, you nominate the most influential innovations of the past 60 years. I will not be alone in reminding your readers that two of the most significant inventions of the last 60 years are DNA cloning and sequencing ( and ), and the monoclonal antibody ().
Both these technologies opened previously inaccessible windows into living things.
The editor writes:
• The inventions were chosen by our panel of science historians.
In defence of organic food and farming
Michael Le Page is wrong to tell people not to eat organic if they care about the planet (3 December, p 21). He misreads the evidence, which shows organic is generally the better choice.
If we want to stop dangerous climate change we need to reduce waste and eat a different mix of foods, particularly less meat than we average in the EU and the US, rather than relying on more efficient production. Choosing organic food doesn't let us off the hook from changing our diets, but it can help achieve the best outcome through those changes.
Growing crops for animal feed drives tropical deforestation. There is a strong case for choosing meat and dairy fed largely on forage. Organic labels help us find it. As GM crops are grown largely for animal feed, they are a red herring. Despite Le Page's enthusiasm, they have little if any productivity advantage.
Le Page is right that organic farms have a lower yield, around 20 per cent on average. This is about the same as the saving they deliver per hectare, so little difference on that count, though they also sequester more carbon in soil. But as they average 50 per cent more wildlife, organic food is generally the better choice despite the yield difference.
In defence of organic food and farming
Michael Le Page calls on us to stop buying organic food “if we really want to save the planet”. This was an excellent example of taking aim at people who put slogans before evidence, but not following the argument through to its obvious conclusion.
The to grains varies between about 50 for beef down to about 3 for eggs and chicken.
The big question isn't should you eat organic, but should you eat animals. And if you care about the planet (or the animals), the answer is no.
For rapprochement with climate change deniers
You headlined Alice Klein's call for environmental groups to be free to use the courts “All voices must be heard on climate” (5 November, p 21). Really? Even those of climate change deniers?
But perhaps they should be heard. Writing of “healing the nation”, Aviva Rutkin describes ways in which groups with polarised views are being brought together (p 18). Could a similar approach bring about a much-needed rapprochement across the climate change divide?
Eating fossil fuel, now and back then
“All of the food you've ever eaten originated with sunlight captured by plants just a few months or years before you ate it,” you say in reporting animal feed grown on methane (19 November, p 10). I often buy coleslaw that contains “vinaigre d'alcool” – which is made from alcohol synthesised from ethylene, derived from petroleum. I am partly fuelled by fossil fuel.
Eating fossil fuel, now and back then
Michael Le Page says the idea of bacterial conversion of methane was first explored by Statoil. But ICI built a plant to produce 50,000 tonnes of animal feed per year, grown on methanol, made from methane (). The firm was in discussions with the Soviet Union, where similar work using other hydrocarbon sources was in progress in the 1960s.
Apparently, economic factors killed the ICI product Pruteen. It will be interesting to see if advances in technology can make the new generation of bacterial protein products viable.
Low-tech solutions for arid and degraded soil
Ricard Solé suggests releasing genetically engineered bacteria into arid degraded landscapes, for example, to produce a water-retentive polymer to help plant growth (1 October, p 36). Another approach to degraded land restoration has been adopted at a national level in Ethiopia and in other African and South American countries. Called permaculture, this focuses on rainwater conservation in arid areas and management of this water source, which can be substantial even if very seasonal. “Grey water” can also be recycled. Relatively simple and cheap technologies can also help restore soil. For example, contour-hugging swales allow much more rain to percolate into the soil and mulching with waste fibre reduces evaporation and adds nutrients.
Science still needs human translators
As a translator myself, I was disturbed that Nello Cristianini asserts more than once that machines can deliver “usable” translations from one language to another (29 October, p 37). Maybe: but only in very limited and banal applications. Fortunately, human language retains such a rich variety of nuance, style and vocabulary that anything truly worth reading in one language requires a human to render it intelligible in another language.
This makes it all the more depressing that in the same issue, you reviewed The Hidden Life of Trees, originally published in German, without crediting the translator – Jane Billinghurst. Human translators play a vital role in the interchange of ideas across language barriers, and without their efforts science would be the poorer.
A dark matter shortage threatens our streets
You tell us that dark matter makes up 84 per cent of the mass in the universe (29 October, p 9). A mere 23 pages later, dark matter accounts for only 27 per cent of the universe (p 32).
At that rate, by the next issue we would have run out of dark matter. Physicists who study it will be jobless, and out on the streets causing untold mischief.
The editor writes:
We should have used a few more words: dark matter makes up 84 per cent of the matter in the universe, but only 27 per cent of the universe as a whole if you include “dark energy” .
Monk seals achieving enlightenment
You report monk seals being found lying motionless on the seabed (26 November, p 15). Can I suggest that said seals were meditating? Did they check for “Ummmm” sounds?
For the record
The National Geographic explorer-in-residence commenting on fishing is (3 December, p 18).