Tag Archives: zoology

Eagle-eyed eagles and blind, breathless fish

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Secret Worlds: The extraordinary senses of animals by Martin Stevens, reviewed for New Scientist, 21 July 2021

Echo-locating bats use ultrasound to map their lightless surroundings. The information they gather is fine-grained — they can tell the difference between the wing cases and bodies of a beetle, and the scales of a moth’s wings. The extremely high frequency of ultrasound — far beyond our own ability to hear — generates clearer, less “blurry” sonic images. And we should be jolly glad bats use it, and these creatures are seriously noisy. A single bat, out for lunch, screams at around 140 decibels. Someone shouting a metre away generates only 90.

Since 2013, when his textbook Sensory Ecology, Behaviour, and Evolution was published, Martin Stevens, a professor at Exeter University in the UK, has had it in mind to write a popular version — a book that, while paying its dues to the extraordinary sensory abilities of animals, also has something to say about the evolution and plasticity of the senses, and above all the cost of acquiring them.

“Rather than seeing countless species all around us, each with every single one of their sense being a pinnacle of what is possible,” he writes, “we instead observe that evolution and development has honed those senses that the animal needs most, and scaled back on the others.” For every eagle-eyed, erm, eagle, there is a blind fish.

Stevens presents startling data about the expense involved in sensing the world. A full tenth of the energy used by a blowfly (Calliphora vicina) at rest is used up maintaining its photoreceptors and associated nerve cells.

Stevens also highlights some remarkable cost-saving strategies. The ogre-faced spider from Australia (Deinopsis subrufa) has such large, sensitive and expensive-to-maintain eyes, it breaks down photoreceptors and membranes during the day, and regenerates them at night in order to hunt.

Senses are too expensive to stick around when they’re not needed; so they disappear and reappear over evolutionary time. Their genetic mechanisms are surprisingly parsimonious. The same genetic pathways crop up again and again, in quite unrelated species. The same, or similar mutations have occurred in the Prestin gene in both dolphins bats, unrelated species that both echolocate: “not surprising,” Stevens observes, “if evolution has limited genetic material to act on in the first place”.

Stevens boils his encyclopedic knowledge down to three animals per chapter, and each chapter focuses on a different sense. This rather mechanistic approach serves him surprisingly well; this is a field full of stories startling enough not to need much window-dressing. While Stevens’s main point is nature’s parsimony, it’s those wonderful extremes that will stick longest in the mind of the casual reader.

There are many examples of familiar senses brought to a rare peak. For example, the whiskers of a harbour seal (Phoca vitulina) help it find a buried flatfish by nothing more than the water flow created by the fish’s breathing.

More arresting still are the chapters devoted to senses wholly unfamiliar to us. Using their infra-red thermal receptors, vampire bats pick out particular blood vessels to bite into. Huge numbers of marine species detect minute amounts of electricity, allowing them to hunt, elude predators, and even to attract mates.

As for the magnetic sense, Stevens reckons “it is no exaggeration to say that understanding how [it] works has been one of the great mysteries in biology.”

There are two major competing theories to explain the magnetic senses, one relating to the presence of crystals in the body that react to magnetic fields, the other to light-dependent chemical processes occurring in the eyes in response to magnetic information. Trust the robin to complicate the picture still further; it seems to boast both systems, one for use in daylight and one for use in the dark!

And what of those satellite images of cows and deer that show herds lining themselves up along lines of magnetic force, their heads invariably pointing to magnetic north?

Some science writers are, if anything, over-keen to entertain. Stevens, by contrast, is the real deal: the unassuming keeper of a cabinet of true wonders.

Can you use a bottle opener?

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Visiting the Baltic in Gateshead for Animalesque: Art across species and beings.
For New Scientist, 15 January 2020.

EXHIBITIONS about our relationship with the environment tend to be bombastic. Either they preach doom and destruction, or they reckon our children will soon be living lives of plenty on artificial atolls.

Animalesque at the Baltic Centre for Contemporary Art in Gateshead, UK, knows better than this. In an international selection of art, sculpture and film, curator Filipa Ramos points out how little we know about other species, and how much we might still learn. With this humility comes hope that we can reform our relations with Earth.

Research has a major role to play, but it can only go so far. One unassuming TV monitor is screening a video from Tupilakosaurus, a long-running project by Danish-Greenlandic artist Pia Arke. It is a telling but not unsympathetic satirical film, in which examinations of a fossil dinosaur throw up folk tales, mangled histories and surreal mountains of paperwork as researchers try to represent and classify the Arctic’s life and history.

Often, we find out about other species only as we are evicting and replacing them. This happened to the Malayan tiger, which now numbers just some 300 wild cats in the Malay Peninsula. 2 or 3 Tigers (2015) by Singaporean artist Ho Tzu Nyen is a 19-minute, two- screen video, made using CGI and some very dodgy operatic singing, about the were-tigers of Malayan folklore. As ancestors, companions, competitors, protectors, destroyers and gods, tigers were central to the indigenous culture. Western settlers couldn’t find any there, however, until one sprang out of the forest in 1835 and attacked a hapless surveyor’s theodolite.

Our most stable cross-species relationships are with domesticated animals, even if they are sometimes discomforting or guilt-ridden affairs. In French artist Pierre Huyghe’s Untitled (Human Mask) (2014), a macaque explores an abandoned restaurant in Fukushima, Japan, an area gutted by the 2011 tsunami. Identifying the species of our protagonist takes a while. You would be forgiven for thinking you were watching a girl, because the macaque is wearing a wig and an eerily beautiful mask (pictured above).

The uncanny collision of categories (girl and pet, puppet and creature) only becomes more dizzying when you discover that Huyghe recruited his “star” from a Tokyo restaurant where the macaque spent many apparently happy hours working as a waiter.

It is a film of great pathos, more moving and less disturbing than this bald description suggests. It speaks to our difficulty understanding other animals, steeped as we are in human concerns.

The difficulty is real, can research help us? Degreecoordinates, Shared traits of the Hominini (humans, bonobos and chimpanzees) (2015) attempts it. For this, UK artist Marcus Coates worked with primatologist Volker Sommer to list questions relevant to all three: do you resolve conflicts using sex? Can you use a bottle opener? Do you kiss? Are you preoccupied with hierarchy and status?

Human answers vary, but so do those gleaned from studying individual chimps and bonobos. The differences between individuals of each of the three species far exceed those across species. Animalesque celebrates what we share – and what we can learn.

 

The sooner we pave over this lot, the better

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Venom: Killer and cure ran at London’s Natural History Museum to 13 May 2018…

Londoners! This holiday season, why not take the children along to the Natural History Museum? Its new exhibition Venom: Killer and cure brims over with fascinating and entertaining stories.

Have you heard about the emerald cockroach wasp (Ampulex compressa), which zombifies its cockroach prey with its sting before laying an egg on it that hatches into a larva that eats the cockroach alive while knowing, somehow, to leave its vital organs till last?

Too strong? Then how about the paralysis-inducing bites of the marine bloodworm (Glycera dibranchiata), whose copper-reinforced teeth are one of the toughest known structures in the natural world?

Oh, dear. There must be something child-friendly round here… How about the deer fly (Chrysops sp.)? The males feed exclusively on nectar! Unfortunately, the females feed exclusively on blood and have evolved an anticoagulant venom to keep their meals flowing.

Nods to some ingenious medicine aside, Venom seems hell-bent on convincing visitors that “nature” is a state of perpetual, terrible and gruesome conflict, and that – if your environmental competitors have their way – your whole lived experience is going to be filled with excruciating pain.

Those with strong enough stomachs will marvel at the ingenuity of nature’s torturers. Even the Iberian ribbed newt (Pleurodeles waltl), which hardly sounds the fiercest animal in the pantheon, has ribs which burst out through its poisonous skin to deter predators.

Those of a philosophic bent will appreciate the show’s underlying narrative, explaining how human cunning makes us the most efficient, though by no means the only, harvester of venom. There’s a sea swallow (Glaucus atlanticus) here, in the form of an extraordinarily delicate and beautiful glass model made by Leopold and Rudolf Blaschka. This pretty sea slug, about 2.5-centimetres long, eats Portuguese man-of-war (Physalia physalis) and collects their venom in its own tentacles, which it fires at predators to defend itself.

The fine-art crowd will thrill to artist Steve Ludwin’s 30-year project of no certain purpose: injecting himself with snake venom. Those of a literary bent, meanwhile, will savour the elegant phrasing of Justin Schmidt’s sting pain scale. Of the Western yellow jacket wasp (Vespula pensylvanica) he writes: “Hot and smoky, almost irreverent. Imagine W. C. Fields extinguishing a cigar on your tongue.”

Venom shows London’s Natural History Museum at its best: the exhibition is intimate, but not claustrophobic; unafraid of detail, but eminently accessible; visually arresting, but not exhausting.

I left trembling, angry and depressed. Had the show let me down? Quite the contrary: if anything, it had over-delivered.

How long, I wondered, must we put up with this ghastly horror-show world of ours? Why should we have to tolerate the way competing slow lorises (Nycticebus sp.) inflict festering wounds on each other, and male emperor scorpions (Pandinus imperator) feel the need to sting their females before they dare broach the subject of sex?

Venom has convinced me that nature is vile. It is pitiless and disgusting, and the sooner we pave over it the better.

The boring beasts that changed the world

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Visiting the Museum of Ordinary Animals exhibition for New Scientist, 4 November 2017

SOME animals are so familiar, we barely see them. If we think of them at all, we categorise them according to their role in our lives: as pests or food; as unthinking labourers or toy versions of ourselves. If we looked at them as animals – non-human companions riding with us on our single Earth – what would we make of them? Have we raised loyal subjects, or hapless victims, or monsters?

This is the problem that The Museum of Ordinary Animals sets out to address. This show has been artfully, but still none-too-easily, stuffed into the already famously crammed setting of the Grant Museum, a 19th-century teaching collection packed full of skeletons, mounted animals and specimens preserved in fluid.

The exhibition, a sign announces, “begins in front of you, behind the dugong”. The corridor between cases is narrow. Easing past visitors distracted by a glass case of dolphin heads, I shave past the enormous, grinning skull of a saltwater crocodile. Here, as in our imagination, the ordinary animals tend to get squeezed out by the extraordinary ones.

The exhibition is small, so go around twice. Spend the first time reading. There is an art to visitor information and the show’s curators have nailed it here, citing just the right oddities and asking just the right questions to tip the viewer into a state of uncertain wonder.

This show, about animals that are useful to humanity, also turns out to be a show about how dangerously peculiar humanity is. The world has been shaped by our numbers, our intelligence and our activity. For example, all pet golden hamsters descend from a single female fetched from Syria in 1930. It was in a group meant for the lab until it was won in a bet.

And the settling of Europeans in Australia from 1788 triggered the fastest catastrophic species loss we know of. Our cats did most of the work, invading more than 99.8 per cent of the Australian land mass. Today, feral cats kill tens of millions of native animals in Australia every night.

The world has been shaped by our beliefs, too. In Europe, it was once common to bury people with their companion animals. Christianity saw off that practice in the late 7th century, because the faith denies that animals have souls. Then, around a thousand years ago, Benedictine dietary rules were formulated. At that time, chickens were feral, quarrelsome and didn’t lay anything like as many eggs as they do now. Today, the chicken is a more or less mindless and sedentary protein factory.

Having learned that humanity isn’t so much a species, more a narrow and superbly weaponised ecosystem, the visitor is ready for a second go. Now the exhibits resonate wonderfully: the bones, the pictures, the jars. Is the subject of Cornelis de Visscher’s mid-17th-century engraving The Rat-Catcher, the catcher himself or the rat in his cage? There are mice used in diabetes research, ironed flat at death and mounted on cards like obscene tombstones. Nearby, a mummified cat head possesses extraordinary innate dignity: no wonder the animal was a focus of worship.

Leaving Ordinary Animals and the museum, I found myself standing under an orange sky, courtesy of Hurricane Ophelia, which had recently brought ash and dust from runaway forest fires to smother Europe’s Atlantic seaboard. Under that dead light, humans gawped at a red sun while, across the road from me, a pet dog, brought to heel, yawned, as though to say: who cares about the sky? Master will feed us. Mistress knows best.

But the exhibition had thrown me out of my complacency, and rarely have I felt less easy with the human project.