In 2010 a study called ‘Three-dimensional Kinematic Analysis of the Pectoral Girdle during Upside-down Locomotion of Two-toed Sloths’ appeared in the journal Frontiers in Zoology. John Nyakatura and Martin Fischer of Friedrich-Schiller-Universität in Jena, Germany, analysed the ‘suspensory quadrupedal locomotion’ of two sloths. They concluded that an earlier biologist had exaggerated, but only slightly, in proclaiming that ‘of all mammals, the sloths have probably the strangest mode of progression’.
Sloths, recorded, by Nyakatura and Fischer (2010)
Others hesitated less to say more. A 2007 book called Victorian Animal Dreams: Representations of Animals in Nineteenth-Century Literature and Culture gets a bit slothful about facts. It says: ‘As the early Victorians well knew, the living descendants of the sloth family not only spend their lives suspended upside down in trees, but are also incapable of walking, and are, in fact, so slow that moss grows on their fur.’
There has been more careful research. In 1981, Frank Mendel of the State University of New York, Buffalo, published a painstaking analysis called ‘Use of Hands and Feet of Two-toed Sloths (Choloepus hoffmanni) during Climbing and Terrestrial Locomotion’ in the Journal of Mammalogy. Four years later, Mendel published a not-quite-identical paper called ‘Use of Hands and Feet of Three-toed Sloths during Climbing and Terrestrial Locomotion’.
A German/Swiss/Panamanian/American team studied slothly sleep. They published a paper in 2008 called ‘Sleeping Outside the Box: Electroencephalographic Measures of Sleep in Sloths Inhabiting a Rainforest’.
Sloths do, now and then, get around. Robert Enders published a paper in 1940 called ‘Observations on Sloths in Captivity at Higher Altitudes in the Tropics and in Pennsylvania’. Enders transported two sloths from their native Panama to his workplace at Swarthmore College in Pennsylvania, where they soon died.
Sloths can shock experts. A 1989 paper called ‘Agonistic Behaviour by Three-toed Sloths’ gives this eyewitness account: ‘A three-toed sloth (Bradypus variegatus) rapidly ascended a cecropia tree, fought briefly and intensely with another adult male, and descended even more rapidly … The social system, visual abilities, and activity budgets of sloths are probably more complex than previously thought.’
In 2010, University of Helsinki researchers examined sloths’ hair. They found that a variety of green algae grows there, and that other scientists ‘have observed a wide range of animals [there], e.g. moths, beetles, cockroaches and roundworms’.
A German/Peruvian team of scientists published a study in 2011 called ‘Disgusting Appetite: Two-toed Sloths Feeding in Human Latrines’.
Evidence: ‘A sloth inside the latrine’
Then there’s always the big question. In 1971, a study titled ‘Why Are Sloths So Slothful?’ investigated whether sloths’ nerves and brain are sloppily slow. Its conclusion: ‘We cannot verify our initial suspicion.’
Nyakatura, John A., and Martin S. Fischer (2010). ‘Three-dimensional Kinematic Analysis of the Pectoral Girdle during Upside-down Locomotion of Two-toed sloths (Choloepus didactylus, Linné 1758).
Rauch, Alan (2007). ‘The Sins of Sloths: The Moral Status of Fossil Megatheria in Victorian Culture’. In Morse, Deborah Denenholz, and Martin A. Danahay (eds). Victorian Animal Dreams: Representations of Animals in Victorian Literature and Culture. Aldershot, Hampshire: Ashgate Publishing.
Mendel, Frank C. (1981). ‘Use of Hands and Feet of Two-toed Sloths (Choloepus hoffmanni) during Climbing and Terrestrial Locomotion’. Journal of Mammology 62 (2): 413–21.
— (1985). ‘Use of Hands and Feet of Three-toed Sloths (Bradypus variegatus) during Climbing and Terrestrial Locomotion’. Journal of Mammology 66 (2): 359–66.
Rattenborg, Niels C., Bryson Voirin, Alexei L. Vyssotski, Roland W. Kays, Kamiel Spoelstra, Franz Kuemeth, Wolfgang Heidrich and Martin Wikelski (2008). ‘Sleeping Outside the Box: Electroencephalographic Measures of Sleep in Sloths Inhabiting a Rainforest’. Biology Letters 4 (4): 402–5.
Enders, Robert K. (1940). ‘Observations on Sloths in Captivity at Higher Altitudes in the Tropics and in Pennsylvania’, Journal of Mammalogy 21 (1): 5–7.
Green, Harry (1989). ‘Agonistic Behavior of Three-toed Sloths (Bradypus variegatus)’. Biotropica 21 (4): 369–72.
Suutari, Milla, Markus Majaneva, David P. Fewer, Bryson Voirin, Annette Aiello, Thomas Friedl, Adriano G. Chiarello and Jaanika Blomster (2010). ‘Molecular Evidence for a Diverse Green Algal Community Growing in the Hair of Sloths and a Specific Association with Trichophilus welckeri (Chlorophyta, Ulvophyceae)’. BMC Evolutionary Biology 10: 86.
Heymann, Eckhard W., Camilo Flores Amasifuén, Ney Shahuano Tello, Emérita R. Tirado Herrera and Mojca Stojan-Dolar (2011). ‘Disgusting Appetite: Two-toed Sloths Feeding in Human Latrines’, Mammalian Biology 76 (1): 84–6.
Toole, James F. (1971). ‘Why Are Sloths So Slothful?’, Transactions of the American Clinical and Climatological Association 82: 131–5.
Research spotlight
‘The Weight of the Leg in Living Men’
by Robert Bennett Bean (published in the American Journal of Physical Anthropology, 1919)
Chair rules
The phrase ‘Tables and chairs on the highway’ has a uniformly accepted meaning in all of England and Wales.
That meaning is legalistic, deriving, we are told, from part VIIA, section 115 (A to K) of the Highways Act 1980, a chunk of parliamentary prose that has the title ‘Provision of Amenities on Certain Highways’. In describing those amenities, though, it makes no mention – none at all – of chairs or tables or any other kind of common furniture. The phrase ‘Tables and chairs on the highway’ appears nowhere – nowhere – in Highways Act 1980.
Nevertheless, many regional and local authorities proclaim that part VIIA, section 115 (A to K) of the Highways Act 1980 – devoid though it is of tables and chairs – gives them authority to regulate all aspects of civic life that are covered by the phrase ‘Tables and chairs on the highway’. And regulate it they do:
Chelmsford borough council publishes a document called ‘Guidelines for Placing Tables and Chairs on the Highway under Section 115 Part VIIA of the Highways Act 1980’.
Westminster city council goes with the shorter title, ‘Guidelines for the Placing of Tables and Chairs on the Highway’.
Eastleigh borough council keeps it terse; they call theirs ‘Tables and Chairs on the Highway’.
What do all the tables and chairs on the highway regulations regulate? Cafes, restaurants, pubs, bars and shops that wish to place tables and chairs outside, on the street.
The regulations mainly deal with safety, trying to ensure ‘that free and safe passage for pedestrians can be maintained’. For some councils – among them Basingstoke, Bath and North-east Somerset, Oxfordshire, and Kensington and Chelsea – that’s about the extent of it.
Other councils have larger concerns. They care, deeply, about the furniture. In the royal borough of Windsor and Maidenhead, the council lets it be known that the ‘type and colours’ of all tables and chairs ‘need approval’.
Similarly, Rushmoor borough council, in Hampshire, says: ‘Upholstered chairs, cushions and similar effects will not normally be considered acceptable … Materials, patterns, colours and style of furniture … must not be too bright, loud or garish (Reason: public and visual amenity) … Variation in design, eg chairs with or without arms, will only be acceptable if from the same design range and of the same general style (Reason: public and visual amenity).’
The almost-neighbouring Eastleigh borough council says: ‘Be a good neighbour! … Only furniture approved by the council may be used … Full details, including metric dimensions, materials and colours, of proposed furniture, ideally accompanied by photographs, illustrations or drawings, will be required as part of the application … The colour of furniture should be attractive but not too bright, garish or overly reflective.’ (Eastleigh borough council also says: ‘The crockery and cutlery used in street cafes should b
e of good quality and a uniform style.’)
Up in Lambeth, however, the council simply says: ‘The type and style of furniture is your choice.’
These policies are all available, at the time I’m writing this, on the official websites of the various councils. Should one of them disappear from the Net, you would likely be welcome to visit the council office and invite the helpful person there to join you in a local cafe – one that has placed chairs and tables on a highway – for a cup of tea and a civilized chat.
Standardized wok men
‘The Effect of Wok Size and Handle Angle on the Maximum Acceptable Weights of Wok Flipping by Male Cooks’, a report in the journal Industrial Health, does more than its title reveals. It also shows how to standardize an intricate physical test.
Many professional wok-users use a big one. Almost all of those woks have a straight handle. That’s bad, say Swei-Pi Wu and Cheng-Pin Ho at Huafan University, and Chin-Li Yen at National Pingtung University of Science and Technology, Taiwan. ‘[We found that] a small wok [about thirty-six centimetres across] with an ergonomically bent handle is the optimal design, for male cooks, for the purposes of flipping.’
Reviewing the effect of five wok angles and three wok sizes on MAWF
Professional wok-weilding cooks are prone to shoulder, neck, lower back/waist and finger/wrist aches and injuries. Wok-flipping brings some glaring risk: ‘The repeated action of swinging the wok up and down, to quickly stir the food in the wok, involves extensive arm and wrist movement, especially dorsi flexion, palmar flexion and wrist radial and ulnar deviation. This non-neutral posture, accompanied by high torque and a high rate of repetition is very apt to cause cumulative trauma disorder injuries in the user’s upper extremity.’
Wu, Ho and Yen had twelve experienced Chinese cooks repeatedly flip woks of three different sizes, with handles at five different angles. The tricky part was standardizing the repetitions for all those people over all those wok-size-and-handle-angle combinations.
Their main tool used was a loudspeaker. They required the cooks to follow a strict protocol. The central part ran like this:
Flip the wok nine times, adding or removing soybeans if the wok feels too light or too heavy.
The loudspeaker says: ‘Adjust the weight, for the last time!’
Flip once more.
The loudspeaker says: ‘Please hold the culinary spatula!’
The loudspeaker says ‘Ready!’, then two seconds later says: ‘Begin!’
Lift the wok and shake it, three times, with the non-dominant hand, lifting the culinary spatula with the dominant hand, ‘to perform the simulated food stir-frying task, first from right to left and then from left to right and from front to back, three times in total’. Then put the wok down. Repeat this cycle eight times.
The loudspeaker says: ‘Please empty soybeans into the container on the left!’
The ‘experimental layout’, as viewed from above
Wu is an old hand at creating such tests. In 1995 he and a colleague published a study called ‘Effects of the Handle Diameter and Tip Angle of Chopsticks on the Food-serving Performance of Male Subjects’. He and a different colleague had earlier published a treatise called ‘An Investigation for Determining the Optimum Length Of Chopsticks’.
Those two studies left some gaps in our knowledge of chopstick optimization. A researcher named Tam Chan filled those gaps in 1999 with a paper called ‘A Study for Determining the Optimum Diameter of Chopsticks’.
Wu, Swei-Pi, Cheng-Pin Ho and Chin-Li Yen (2011). ‘The Effect of Wok Size and Handle Angle on the Maximum Acceptable Weights of Wok Flipping by Male Cooks’. Industrial Health 49 (October): 755–64.
Wu, Swei-Pi (1995). ‘Effects of the Handle Diameter and Tip Angle of Chopsticks on the Food-serving Performance of Male Subjects’. Applied Ergonomics 26 (6): 379–85.
— Chan, Tam (1999). ‘An Investigation for Determining the Optimum Length of Chopsticks’. International Journal of Industrial Ergonomics 23 (1/2): 101–5.
May we recommend
‘Collective Motion of Humans in Mosh and Circle Pits at Heavy Metal Concerts’
by Jesse L. Silverberg, Matthew Bierbaum, James P. Sethna and Itai Cohen (published in Physical Review Letters, 2013)
Cold advice: put a sock on it
Socks over shoes surpass shoes over socks for strolling on slippery city slopes, says a study done in New Zealand. In other words – in the words of the study itself – ‘wearing socks over shoes appears to be an effective and inexpensive method to reduce the likelihood of slipping on icy footpaths’.
Lianne Parkin, Sheila Williams and Patricia Priest conducted an experiment to test the wisdom of a local winter tradition. The trio, based at the University of Otago in Dunedin, published a report in the New Zealand Medical Journal. They explain: ‘There are anecdotal reports that pedestrians who wear socks over top of their footwear are less likely to slip and fall in icy conditions. Advocates of this practice include our local council (in Dunedin) which advises residents who prefer to walk (rather than drive) in icy conditions to “put a pair of old socks over your shoes to increase grip” ’.
Their city has some famously hilly sections that grow treacherous come wintertime: ‘Damp weather followed by freezing conditions can transform a quick journey to work into a lengthy and perilous expedition.’ They ‘initially considered recruiting volunteers to walk down a short suburban street (Baldwin Street) which, according to the Guinness Book of Records, is the steepest street in the world’. But legal and other considerations led them instead to send people down two other streets, with merely San Francisco-grade inclinations.
Parkin, Williams and Priest found it simple to recruit volunteers: ‘To be eligible for inclusion in the trial, passing pedestrians simply needed to be travelling in a downhill direction. It was decided a priori that persons already wearing socks over their shoes would not be eligible.’
The research team documented every fall, and wrote comments (such as ‘walked confidently’, ‘clung to fences or parked cars’, ‘crawled’) about the demeanour of each volunteer during their descent.
Not all experiments give clear results. This one did. ‘Wearing socks over footwear significantly reduced the self-reported slipperiness of icy footpaths and a higher proportion of sock-wearers displayed confidence in descending the study slopes. The only falls occurred in people who were not wearing (external) socks.’
Sock inside, on ice
But despite the safety advantage, wearing one’s socks over one’s shoes can create or exacerbate a problem. The problem is of a social nature.
In 1989, two researchers extracted gossip from a group of young (aged seven to eleven) American schoolchildren, asking each child to discuss the reputations of each of their classmates. The kids prattled on about behaviours that, to them, were warning signs of weirdness: ‘eats like a pig, bangs head on desk, sounds like a car, fidgety, acts like a monster, wears socks over shoes’.
The what-other-people-will-think problem cropped up in the Dunedin shoes-over-socks study. Parkin, Williams and Priest note that: ‘although participants in the intervention group were told that they could keep their socks, many (who appeared to have image issues) opted to return them to the outcome assessors – including one young man who promptly fell on leaving the assessment area.’
Parkin, Williams and Priest were awarded the 2010 Ig Nobel Prize in physics for their work.
Parkin, Lianne, Sheila M. Williams, and Patricia Priest (2009). ‘Preventing Winter Falls: A Randomised Controlled Trial of a Novel Intervention’. New Zealand Medical Journal 122 (1298): 31–8.
Rogosch, Fred A., and Andrew F. Newcomb (1989). ‘Children’s Perceptions of Peer Reputations and Their Social Reputations Among Peers’. Child Development 60 (3): 597–610.
May we recommend
‘A Bayesian Approach to Wiggle-Matching’
by J.A. Christen and C.D. Litton (published in the Journal of Archaeological Science, 1995)
Shifty damage done
Archaeologists know that the ground they examine can be literally rather shifty. The reasons for this shiftiness can be disturbing, beastly and even childish.
For many an archaeologist, the greatest treasures are artifacts – ‘objects produced or shaped by human workmanship’, as the dictionary puts it. The exact location of an artifact can be as important as the thing itself. In a dirt heap, what is next to what – and especially, what is on top of or below what – can impart telling information.
Archaeologists have it tough, though, because things do move around underground. Sometimes this is due to the actions of burrowing animals. Over the years, archaeologists have cautioned each other to beware of ants, termites, earthworms, and, even more famously, rats and other rodents.
A 2003 report from South America points out that: ‘There is, however, one animal that despite its regional ubiquity and notable burrowing behavior has received little attention in the archaeological literature: the armadillo.’
Detail: Araujo and Marcelino’s research questions
Writing in the Geoarchaeology, Astolfo Gomes de Mello Araujo, of the Universidade de São Paulo, and his colleague José Carlos Marcelino go into considerable detail. Living in an age of specialization, they focus on one aspect of the armadillo question: ‘Although it seems clear that armadillos can move archaeological materials upward’, they write, ‘previous studies have not considered whether they also move artifacts downward.’
This is Improbable Too Page 12
