Pets cost the Earth
Your editorial on the environmental impact of pets comes at a poignant time in the autumn of my veterinary career (24 October, p 5). I have suffered guilt for some time over my role in the excesses of the pet industry.
Despite the dire warnings of global overconsumption, indulgence in our pets has skyrocketed over the past decades, driven in part by the pet food industry’s creation of “niche” diets. This plethora of regimes, based on purportedly superior ingredients, either cater for the pet’s several developmental states or aid in the treatment of diseases. The veterinary profession, for better or for worse, has tagged along with this niche market of specialist pet food, with scant evidence-based science as to the enhanced well-being of the pet that results.
In a carbon-taxing system, pet food should be taxed: a low tax for pet food based on abattoir waste products, with prices increasing when human food is added. Status-symbol pets may be less appealing under this system.
Changes to pet registration laws, where fees are geared to small, medium and large breeds, would also make a large breed less attractive as a pet, or at least make owners more socially aware.
From Nazzareno Gottardi
I decided to do a small calculation for Kate Ravilious after reading her article on the ecological pawprints of pets (24 October, p 46). Based on a 4.6-litre Toyota Land Cruiser, travelling 10,000 kilometres per year at an average of 19 litres per 100 km corresponds to an approximate average consumption of 1500 kilograms of fuel, which equates to about 4.5 tonnes of carbon dioxide per year. That damage to the environment must be added to the carbon footprint of the car, though that was not included in the calculations. My dog will never exhale enough CO2to compete with these emissions, nor is he releasing CO2 by oxidising fossil fuels.
Articles like this, while addressing real issues in an amusing way, distract most people from the real tragedy of the destruction of our environment.
Schuttrange, Luxembourg
From Clare Middle
Your editorial discusses the potentially high carbon footprint of pet dogs and cats fed commercial pet foods.
A “greener” option is available, which also accords better with the diet the animals would have eaten as they evolved.
Dogs have not changed much since they first befriended humans in Stone Age times, and neither have their digestive systems. They can live perfectly healthily off the bits of meat humans don’t fancy, preferably from the smaller animals that would have been their natural prey. The best food for dogs includes chicken giblets, neck, wings and frame, lamb neck, heart, kidneys and liver. A similar logic follows for cats 鈥� chicken neck, wing parts, whitebait and fish offcuts are a good choice.
These should all be fed raw to the animal, and supplemented with bits of vegetables and fruit you don’t want, either cooked or pulverised. Many other leftovers can be added: the egg that broke, the yogurt that expired and the oil from the fish can 鈥� whichever bits your pet likes.
Perth, Western Australia
Engineered nutrition
Your editorial made a laudable public stand in support of genetic modification as a way to produce nutritionally enhanced crops (31 October, p 5). But by focusing on one crop, produced by one company in the developed world, you overlook the most important activity in this area.
Most nutritional GM is focused on improving the nutrient profiles of the staple starches consumed by the poorest people in the least developed countries. The largest programme is run by the NGO and concentrates on putting the three micronutrients that underlie most deficiency diseases 鈥� provitamin A, iron and zinc 鈥� into seven crops that dominate the diets of the rural poor. This research is funded almost exclusively by foundations and governments; there is not much money to be made out of subsistence farmers.
Seven large trials are about to begin. If they are successful, their impact will be rapid and vast, reducing iron-deficiency anaemia in women and blindness in their children caused by a shortage of vitamin A.
This may transform public health in the developing world. It would also transform the public debate about genetically modified crops, even in Europe.
Crash time
Douglas Fox relates how researcher David Eagleman asked volunteers to endure 30 metres of free fall into a safety net while wearing an LED device to determine whether altered perception or a change in the speed of observation could account for the feeling that time slows down during stressful events. Eagleman decided the phenomenon must be a “trick of memory” because his volunteers could not distinguish between rapidly alternating images on the LED device (24 October, p 32).
It seems to me that an alternative explanation for the results might be that while vision, as in frames per second, doesn’t speed up, mental processes could have. If that were true, the results would be the same: the subjects would not see the two images that Eagleman hoped would show that their perception had speeded up.
When my brakes failed in my Formula Vee race car at about 80 miles per hour, I had to spin the car sideways with only 15 feet to impact. I had time to consider where to place my head in relation to the side roll bars. I went through the different positions I could adopt, and tried to recall if there was any recommendation from the helmet manufacturer or if I knew of other racers who’d had a similar accident. I then thought that I regretted not anticipating such a crash and thinking about head position.
It was then that I thought I was wasting time and had to make up my mind; I decided to place my head as centrally as I could between the bars and to stop looking towards the earth bank I was about to hit. When I turned away, the bank was about 4 feet away, so my thought processes took less than 0.1 seconds. To me, it seemed like time slowed down, but I still believe my mind speeded up because I needed it to.
A year later when I crashed head on into a wall at about 90 mph there was no decision to make, so time did not speed up.
Cleaner killing
Andy Coghlan discussed the possibility that calves may feel pain after Jewish or Muslim ritual slaughter (17 October, p 11), and the suggestion that stunning before slaughter is more humane.
I would refer your readers to a far earlier article (23 October 1999, p 6) in which John Bonner describes the discovery of brain tissue in the vascular system of 1 in 16 bolt-stunned cattle that were then subjected to “pithing”: having their brains scrambled by a metal pole in order to prevent the animal reflexively kicking out.
The brain tissue, Bonner’s article reported, could reach the edible parts as the heart continued to beat and pump the brain tissue round the body for several minutes after slaughter. This would seem to introduce a risk of spreading prions and BSE.
I would suggest that ritual slaughter, when performed properly, carries fewer risks to the animal and to the meat-eater.
Naked nerves
I read with interest Elaine Morgan’s explanation for human hairlessness (19 September, p 28) and I would like to propose my own alternative: our nakedness must be to do with producing more vitamin D in the skin.
Vitamin D is a fat-soluble hormone with a multiplicity of actions, particularly in the central nervous and immune systems. Small quantities are obtained from the diet, but larger amounts are created by sunlight acting on precursors in bare skin. Vitamin D is thought to be important in maintaining the integrity of the myelin sheath which insulates nerve fibres. Levels tend to be low in winter and in those who have the demyelinating autoimmune disorder multiple sclerosis. It is thought that vitamin D affects the expression of certain genes common in people with MS. Presumably vitamin D has other as-yet-undiscovered genetic interactions.
So perhaps when an early Homo or Australopithecus underwent a mutation or two and became hairless, further mutations put the additional vitamin D to good use in improving myelin insulation and allowing faster and more reliable neurotransmission. That could have been a main factor in instigating the explosive brain development in our lineage over the past 3 million years.
As Morgan implies, the benefits would have to be huge to outweigh the incredible energy costs of being naked in a frigid climate. One of those benefits would have been endowing our ancestors with the nous to make clothes for trips out of Africa.
It would be interesting to investigate this further: exactly how much vitamin D can the hairy skin of wild chimps manufacture and what is their normal vitamin D blood level? Rickets in young chimps in captivity and vitamin D deficiency in the adults seems to be a recognised problem, which is treated with supplements and increased sun exposure. Could the myelin composition of chimps differ from ours, and have the genes controlling myelin synthesis changed over time?
Engender ambition
It was disappointing to read a gender assumption in Michael Bond’s article on interview techniques. He explains that you are more likely to get the job if the interviewer gets on with you: “If an employer thinks you’re likeable, he may also think you are intelligent…” (UK edition Graduate Careers Special, 24 October, p 7)
Men far outnumber women in the top managerial positions, as they do in science. As a science magazine, I would hope you would be particularly sensitive to gender balance and promote opportunities for women in areas where they may have felt discouraged from applying.
As small a detail as this is,the cumulative effect of assumptions ingrained in our culture often shapes people’s choices and ambitions.
For the record
鈥� In our article on supersymmetry, we should have stated that Nathan Seiberg and Edward Witten work at the Institute for Advanced Study, Princeton (14 November, p 36).
鈥� Alvaro Montenegro is assistant professor at St Francis Xavier University in Nova Scotia, Canada (14 November, p 6).