The Lizards That Fell to Earth
The Bible tells of frogs that fall from the sky. Biologists, on the other hand, tell of lizards that fall from trees.
The biologists – William Schlesinger, Johannes Knops, and Thomas Nash – recount in great detail how they discovered an unsuspected truth about lizards. Their study ‘Lizardfall in a California Oak Woodland’, published in the journal Ecology, is a blow to the reputation of a species once admired for its surefootedness. It’s the story of the reptiles’ ungraceful fall into the abyss – in this case a plastic bucket – and of the detectives who documented that fall.
Western fence lizards spend a lot of time in trees, walking up and down the branches. But, when running after insects or away from predators, say Schlesinger, Knops, and Nash, they frequently lose their grip.
Though based at Duke University in North Carolina and at Arizona State University, the team went a-bucketing far from home, on a southeast-facing oak woodland slope in Monterey County, California. There they set big plastic tubs under the trees to see what might come their way.
N.B. Lizardfall plummets in December
Lizards are what came their way, for the most part. Bucketloads of lizards. Bucketloads of leaping lizards one might say – but that would be enhancing the facts.
This was no quick overnight stakeout. For nearly three years, beginning early in 1990, Schlesinger et al. set their buckets beneath forty trees, returning monthly to peek inside. In a rousing, earthy passage, they describe a moment of realization, and the effect it had on the investigation: ‘When we realized that lizards could not escape over the 43-centimeter sidewalls of the collectors, we began to keep records of lizardfall in May 1990. (Lizards could not climb into the buckets, which slope outwards slightly from bottom to top and which were anchored in the field with short metal stakes after December 1991.) In the summer of 1991 we increased the frequency of our collections to every 2 weeks to prevent the death of captured lizards by dehydration, and in April 1991 we began a protocol of toe-clipping so we could record the recapture of fallen lizards.’
All told, they collected hundreds of fallen western fence lizards. This shattered the animals’ reputation for surefootedness, which had been enshrined, for nearly two years, in B. Sinervo and J. B. Losos’s 1991 deadpan report ‘Walking the Tight Rope: Arboreal Sprint Performance among Sceloporus occidentalis Lizard Populations’.
As documented by Schlesinger et al., the life of a fallen lizard can be grim. The recidivist rate is high. In police-blotter style, the report says: ‘Thirty-three percent of the recaptured lizards were found under the same tree as their previous fall.’
And one case was heartbreaking. It’s mentioned in a single, plain sentence: ‘One particularly clumsy individual was captured five times (in four different collectors) between 20 May 1991 and 16 July 1991, when it was found dead in a collector.’
Schlesinger, William H., Johannes M. H. Knops, and Thomas H. Nash (1993). ‘Arboreal Sprint Failure: Lizardfall in a California Oak Woodland.’ Ecology 74: 2465–67.
Infestigated
Hopes are safer than aspirations, as regards small insects keeping their proper place. Hopes do not by themselves cause an infestation, in the head of a human being, of gnats, midges, anthomid flies, Collembola, and wasps parasitic upon the flies. Aspirations can, and sometimes do. This fact slowly, then suddenly, dawns on anyone who reads a report called ‘“Myiasis” Resulting from the Use of the Aspirator Method in the Collection of Insects’, which was published in the journal Science in June 1954.
The author, Paul D. Hurd Jr, of the University of California, Berkeley, begins with two paragraphs of impersonal description, written in a rather passive voice. There we learn that ‘the aspirator, an apparatus generally designed to collect insects by suction, consists of a vial into which is fitted, by means of a stopper, two pieces of copper tubing, one of which is directed toward the insect and the other is attached to a length of rubber tubing, which during use is placed in the operator’s mouth. Across the end of the copper tubing leading to the operator’s mouth a fine mesh brass screen is secured. This, of course, is to prevent the aspirated insects being drawn out of the vial and yet provide a free airway between the insect being aspirated and the operator.’
In the third paragraph, in an instant, things perk up. It says: ‘Approximately two months after the completion of the past summer’s work at Point Barrow [Alaska], I became ill. During the week following the onset of illness four major groups of insects (Coleoptera, Collembola, Diptera, Hymernoptera) were passed alive from the left antrum of the sinus.’
The rest of the report maintains this lively tone. It also supplies factual detail, in abundance. Which specific representatives of those four groups of insects emerged from the author’s sinus? He supplies this data: ‘three adult rove beetles (Staphylinidase), Micralymna brevilingue Schiødte; 13 fungus gnat larvae (Mycetophilidae), Boletina birulai (Lundstrom); three egg parasite wasps (Mymaridae), Mymar sp.; and about 50 springtails (Collembola), Isotoma olivacea Tullberg.’
‘Myiasis’ means infestation. This particular infestation had plenty of time to get a start, and then to fulfil its potential. Hurd aspirated insects for four to six hours every day over the course of an entire summer. Summers in Alaska are shorter than summers in the middle latitudes, but they are long enough for nature to take its full course.
Hurd was given pause. ‘I would like to suggest, he writes, ‘that those persons who utilize this apparatus so modify it that the flow of air will not be toward the operator’s mouth.’
In the report’s final paragraph, Hurd drops his restraint, hinting that the tale – and his emotions – are deeper than he’s let on.
‘It is almost unbelievable’, he writes, ‘that the insects should have undergone several stages of their metamorphosis within the sinuses.’
Hurd, Paul D., Jr (1954). ‘“Myiasis” Resulting from the Use of the Aspirator Method in the Collection of Insects.’ Science 119 (3101): 814–15.
Exposure at Sea
‘Courtship Behaviour of Ostriches Towards Humans Under Farming Conditions in Britain’ is the title of a scientific study written by Charles Paxton and three colleagues. In 2002, when I informed Paxton that his team would be awarded that year’s Ig Nobel Prize in biology, he took the news matter-of-factly. ‘I’m not surprised to be getting this telephone call,’ he said, ‘but I expected that if I ever won an Ig Nobel Prize, it would be for my work with sea monsters.’
Paxton and two other colleagues, Erik Knatterud and Sharon Hedley, published a study about sea monsters in 2005 that promised to change the way scientists look at the subject. Paxton and Hedley are at St Andrews University in Scotland; Knatterud is based in Stavsjoe, Norway.
Here are four surprising facts about Charles Paxton:
ONE: Of the four ostrich researchers, he was the ostriches’ sexual favourite.
TWO: It would be misleading to say that he studies ostriches. Paxton no longer works with long-necked, sexually aggressive birds. These days his main research work concerns fish.
THREE: He is a friend of the celebrated and glamorous biologist Olivia Judson, whose book, Dr Tatiana’s Sex Advice to All Creation, which presents detailed deliciously graphic how-to sex advice from the fictional doctor to a variety of fish, birds, reptiles, mammals, slime moulds, and other species, was all the rage several years ago. Paxton and Judson were students together at the University of Oxford.
FOUR: It is slightly misleading to say, as some people do, that he studies sea monsters. What he studies are reports about sea monsters. Sea monster reports are, for him, part scholarly, part pastime.
You may have noticed hints of a pattern in facts number one, two, and three: sex. Charles Paxton’s newest sea monster report, published in the Archives of Natural History, continues the pattern. It gives a fresh interpretation to an old sea-monster sighting.
In 1741, a Danish-Norwegian missionary named Hans Egede published what became a famous accou
nt of ‘a most dreadful monster’ that appeared off the coast of Greenland. ‘The case is interesting,’ the modern scientists write, ‘in that Egede had drawn and described a number of large northern whale species in his book so he obviously felt the “dreadful” monster was something different.’
Paxton says that most historians have relied solely on a bad translation of Egede’s book. He and his colleagues applied modern biological insights to the case.
Egede’s animal had a serpent-like tail that appeared out of the water when the rest of the beast had disappeared. But rather than a tail, Paxton et al. say, this was most likely a penis. They present photographs of well-equipped male whales, and also a drawing from Egede’s book, in which we see the sea monster’s serpent-like tail. The latter is remarkably similar to what we see in the photographs.
Detail from Egede’s monstrous account of 1741 (top); North Atlantic right whale penis of 2001 (bottom). Photograph reproduced by permission of New England Aquarium, Boston, Massachusetts.
The case is not proved definitively, but it should be an inspiration to both biologists and whale-watching tourists.
Paxton, C. G. M., Erik Knatterud, and Sharon L. Hedley (2005). ‘Cetaceans, Sex and Sea Serpents: An Analysis of the Egede Accounts of a “Most Dreadful Monster” Seen Off the Coast of Greenland in 1734.’ Archives of Natural History 32 (1): 1–9.
Fold When Wet (If Naked)
Yuri Glebovich Aleyev used an electric winch to tow naked women underwater at speeds of two to four metres per second. Later, his colleagues, when they peered at Aleyev’s films and photos, had reason to be upset. What they saw was not what anyone, except maybe Aleyev, was expecting.
Aleyev, who died in 1991, was one of the world’s great experts on nekton, which is an obscure word for animals that swim where they wish, rather than merely drifting along. Plankton are not nekton. Fish, dolphins, and people are. Aleyev spent much of his life and ingenuity trying to tease out the secrets of how good-swimming creatures swim so well. The naked women served as stand-ins, so to speak, for wild dolphins.
Aleyev wanted to test something many of his colleagues believed: that dolphins slip so easily through the seas because their skin forms special, undulating folds. Those folds, hypothesis had it, keep the water flowing smoothly – rather than turbulently – past the speeding dolphin.
Others had tried photographing dolphins in action, expecting to capture clear images of mighty, mobile ripples travelling down their bodies. However, film after film failed to show the telltale lines. Thus came Aleyev to the quarrel, and thus, at his invitation, came forty professional swimmers to a pool. Using basic, pithy engineering language (including a mention of the difficult-to-describe-in-words Reynolds number), Aleyev explained that: ‘women are similar in body size to average-sized dolphins of the Delphinus type. For women 160–170 centimeters tall swimming with arms stretched forward at a speed of 2.0–4.0 meters/second, the range of Reynolds numbers is about 3.0 X 106 to 9.0 X 106, which is entirely inside that most usual for dolphins... The body surface of the typical woman may be considered to a sufficient approximation hairless, which is characteristic also of dolphins.’
In the early 1970s, Aleyev produced three papers about his experiments. He later summarized them, along with many of his other discoveries, in a book called Nekton, written in Russian. An English translation came out in 1977 from a Dutch publishing company with the curious name Dr W. Junk. The volume includes a generous selection of action photos of the women, who are not quite as hairless as advertised, and a few corresponding pictures of dolphins.
The images tell a tale that Aleyev interprets in the accompanying text. Skin ripples do appear, but only when the women (and the dolphins) are in a sharp spurt of acceleration or when they move at the very highest speed. These are not at all ‘the result of the contraction of certain trunk and skin muscles’. They are merely passive ripples in the aquatic breeze, akin to wind-furls in a flying flag. And when the skin-folds form, they probably slow down the swimmer, rather than speed her up. Thus did Yuri Aleyev and his underwater camera and his electric winch, assisted by forty skilled swimmers, destroy a biological doctrine of his day.
It was a Fish who told me about Aleyev’s experiment – Frank E. Fish, who studies fish and who, when above sea level, often legitimately acts the role of a biology professor at West Chester University in Pennsylvania.
Aleyev, Yuri Glebovich (1977). Nekton. The Hague: Dr W. Junk. See 264–78.
On Monkey Vomit (For Those Who Want to Know)
‘Researchers have given little consideration to vomiting in nonhuman primates.’ Quite so. A new report called ‘Vomiting in Wild Bonnet Macaques’ begins with that statement, and tries to remedy the deficiency.
Elizabeth Johnson, Eric Hill, and Matthew Cooper published their study in the International Journal of Primatology. Johnson is at Oglethorpe University in Atlanta, Georgia. Hill is at Arizona State University, and Cooper at Georgia State University.
They start with a fond look back at the work of earlier vomiting experts. The consensus view, they say, is that vomiting ‘is a theoretically complex behavior that to date lacks a comprehensive explanation’.
Johnson, Hill, and Cooper spent time with macaques, carefully noting when each individual animal vomited and whether it then reingested (for that is the technical term) whatever came up. All told, the scientists compiled ‘both quantitative and qualitative data on observations of 163 instances of vomiting from 2 groups of bonnet macaques in southern India’. They used this data to ‘establish a conservative rate of vomiting in free-ranging macaques’.
The rate is 0.0042 vomits per individual per hour. That’s the conservatively high estimate, using data gathered by watching macaques that live in and near a temple on top of Chamundi Hill, a rocky, forested outcrop near Mysore, in Karnataka, India. But it’s not the whole story. Another group of macaques lives in the Indira Gandhi Wildlife Sanctuary, Anaimalai Hills, Tamil Nadu. These forest-dwellers vomit at a different rate from their temple cousins: 0.0028 vomits per macaque per hour.
The scientists observed closely and keenly. Here is a typical passage from their report: ‘Only 1 adult female in the forest showed interest in another macaque’s vomit; she twice smelled the mouth of an adult female. During observations at the temple we saw 20 different individuals show interest in another’s vomit on 21 occasions. Ten of the individuals were successful in eating some of it on 11 occasions. Of the individuals that ate or tasted another monkey’s vomit, 2 were adult females, 2 were adult males, 3 were juvenile females, and 3 were infants.’
Detail from ‘Vomiting in Wild Bonnet Macaques’
The study builds to a thrilling conclusion. The researchers explain what, to them, is a central mystery about vomiting in wild bonnet macaques. Why, they ask, don’t the macaques simply vomit and walk away? Why do they immediately ‘reingest’ the vomit?
Earlier scientists seem not to have noticed this mystery or, if they did notice, to have offered a good explanation.
The key, according to Johnson, Hill, and Cooper, lies in a simple fact. Macaques have spacious pouches built into their cheeks. Johnson et al. apply some logic. ‘We suggest’, they write, ‘that the tendency to hoard food in their cheek pouches explains why they reingested the vomit.’
The study concludes with a modest statement: ‘Our data offer insight into a normal, but largely ignored, behavior of cercopithecines.’
Johnson, Elizabeth C., Eric Hill, and Matthew A. Cooper (2007). ‘Vomiting in Wild Bonnet Macaques.’ International Journal of Primatology 28 (1): 245–56.
Four
Behave Yourself
(Or Don’t)
In Brief
‘I’m Waiting for the Band: Protraction and Provocation at Rock Concerts’
by Richard Witts (published in Popular Music, 2005)
Some of what’s in this chapter: Sheep personality profiling • Spaced out on the beach, measurably • Seating in cinemas, handedly (in Bulgaria)
• Booing at bigshots • Looking at liars, internationally • Punks and accountants • Clowns of a ministerial turn • Racial cheese profiling • Watching people watch their laundry • Naked in the library • A toilet dilemma • Oscillating, as one will do • Noise-making among the elderly • Chewing delicious food • Chewing distasteful food
Cling Boldly, Sheep
To know – rather than guess – why certain sheep cling to each other while others split off on their own, a person would need to know the size of the group, and also know something about the personalities of the individual sheep. Scientists at the Macaulay Institute in Craigiebuckler, Aberdeen, Scotland, sought this very knowledge when they looked at the loiterings of sheep.
Pablo Michelena, Angela Sibbald, Hans Erhard, and James McLeod (the names of the scientists, not the sheep) wrote up their adventure in a study called ‘Effects of Group Size and Personality on Social Foraging: The Distribution of Sheep Across Patches’. It appeared in 2009 in the journal Behavioral Ecology.
The four scientists observed the meanderings of fifty-eight female Scottish Blackface sheep in tasty green fields, under tightly controlled conditions. Before letting the sheep loiter, the researchers gave each of them a personality test, noting which sheep were bold enough to explore objects with novel smells (lavender, mint, thyme, marjoram, garlic, or coffee) and exotic shapes (a baby’s rattle, a bottle brush, and various baby’s teething rings).
Then they let the sheep loose, in groups of two, four, six, or eight, to graze in grassy arenas. Each arena had some patches of especially desirable (in the scientists’ educated opinion) greenery. That extra-yummy fodder, sprung from extra-fertilized soil, and was allowed to grow especially long so as to be extra-noticeable to the sheep.
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