Letters archive

The article "Sloths grip stronger than humans and other primates" states there is an unexplained left-side bias in their strength. Here is a possible explanation. If, like some animals , they favour using their right hands for fiddly tasks, then they would be hanging on a lot more with their left hands, which would get …

Graham Lawton does well to point out that a civilisation-destroying climate catastrophe with warming of 4°C to 5°C, also known as the "business as usual" scenario, is no longer the most likely outcome, if indeed it ever was( 14 January, p 28 ). However, as he acknowledges, there is much uncertainty in our understanding of …

There is a fundamental contradiction between two of Vaclav Smil's innovations to save humanity. He calls for more efficient photosynthesis, while also suggesting the need for a planetary sunshade to control global warming( 7 January, p 38 ). However, such geoengineering wouldn't only cool Earth, but also reduce the efficiency of photosynthesis at the global …

There is nothing democratising about web3, which runs on the blockchain, the technology that underpins cryptocurrencies. It is about replacing control of the web by giant tech corporations with possible future control of it by criminals and feudal lords( 21 January, p46 ). And, as with cryptocurrencies, you would trade ownership of the web by …

Clare Wilson reports on challenges to the "nil by mouth" rule that patients shouldn't consume liquids for 2 hours before surgery. It is surprising how entrenched medical practices can be! However, she might like to know that, more than 30 years ago, women were allowed to drink and to suck sweets during labour, despite the …

Marlene Zuk warns against attributing feelings to non-human animals that are more commonly ascribed to us, saying it is stifling inquiry. It appears that the notion that any non-human might have fun is something of an anathema( 14 January, p 27 ). Just as we can't know what goes on in a pre-verbal toddler's head …

We are concerned your coverage of Alzheimer's Research UK's Think Brain Health campaign will undermine a vital initiative to raise awareness of widely accepted modifiable dementia risk factors( 28 January, p 19 ). Your article is critical that evidence for dementia prevention comes chiefly from observational studies rather than randomised controlled trials (RCTs). For many …

Your look at the limits of knowledge asks us to imagine a woman who has been brought up in a black, white and grey room, so that everything she sees is in monochrome. She studies colour in the abstract, then goes out to witness a polychromatic world. This is used to exemplify that some knowledge …

I read your article on the power of huge marine avalanches to move massive amounts of material and reshape the ocean floor. I would like to draw your attention to the Pactolus bank off Cape Horn, which has long been a puzzle. Found in 1885, this seamount is thought to no longer exist( 28 January, …

Your feature on the use of sonification to reveal the sounds of space was intriguing. A few years ago, my colleagues and I applied the same technique to listen to the cosmic microwave background. This was achieved by downshifting its radio spectrum into the audible range and using this to filter the wideband random noise …