Touchy- feely The hard, horny bill of a bird may appear a rather insensitive instrument: the perfect tool for capturing, dispatching or butchering prey, but not – you would imagine – for detecting it. Many wading species, however, have a dense concentration of nerve endings near the tip of their bill that enables them to sense the movement of unseen prey. Such species are known as ' tactile foragers'. The yellow- billed stork ( Mycteria ibis), for instance, habitually feeds with its open bill plunged deep into the mud. At the slightest movement of prey, which includes frogs, worms, crustaceans and small fish, the bill snaps shut in a lightning- fast reflex response. The prey is then lifted to the surface and – since the stork, like most birds, has little sense of taste – swallowed in a gulp. Pit stop The African rock python ( Python sebae) – as if not content with its five metres of coils and wicked teeth – has evolved a fiendish extra sense with which to capture a meal. Special heat- sensitive pits on the ' labial' scales around its mouth detect the body heat radiated by passing rodents and other warm- blooded prey. These pits, packed with nerve- endings, can perceive heat changes of less than 0.003 degrees Celsius, enabling the snake both to locate its prey and to work out the direction in which it is moving. The sense data pass instantaneously to the brain, so the python can target its quarry with a lethally accurate strike. This ability proves invaluable in darkness, when eyesight is largely redundant, effectively giving the big snake a form of infrared vision. Current affairs Sharks are more sensitive than any other animal to electrical fields, with the great white shark ( Carcharodon carcharias) able to detect half a billionth of a volt. And the bad news is that all living creatures – that includes you and me – produce an electrical field when moving through water, which immediately alerts sharks' attention. The secret lies beneath the sharks' skin in the form of tiny electro-sensitive organs known as the ' ampullae of Lorenzini' ( named after the 17th- Century Italian biologist Stefano Lorenzini who first described them). Each ampule consists of a jelly- filled canal that opens to the surface by a pore. The pores are plainly visible as dark spots in the skin. But the good news is that scientists have now exploited this acute electro- sensitivity in order to produce a shark repellent for divers: the ' POD' ( Protective Oceanic Device) produces its own electromagnetic field, which disrupts a shark's focus on any potential target. All living creatures produce electric fields – not good news for those in the water. The ' ampullae of Lorenzini' organs that sit just beneath a great white's skin can detect half a billionth of a volt 127 The yellow- billed stork's beak can detect the slightest movement of prey while foraging in muddy waters. No wonder it keeps its mouth open! msafiri Special heat- sensitive pits around African rock pythons' mouths can detect minute changes in air temperature ( as little as 0.003 degrees Celsius) caused by warm- blooded prey nearby
msafiri FICTION 128 L ynn had almost made it to the petrol station when her old Toyota ran dry on the highway. Lucky me, she thought as she pulled on to the verge, seeing the red and yellow flags ahead, the logo on the tall facade. But it was hopeless, she realised as soon as she saw the pile- up of cars on the forecourt. A man in blue overalls caught her eye and made a throat- slitting gesture with the side of his hand as she came walking up: no petrol here either. There were twenty- odd stranded people, sitting in their cars or leaning against them. They glanced at her without expression before turning their eyes again towards the distant city. In a minibus taxi off to one side, a few travellers sat stiffly, bags on laps. Everyone was quiet, staring down the highway, back at what they'd all been driving away from. An oily cloud hung over Cape Town, concealing Devil's Peak. It might have been a summer fire, except it was so black, so large. Even as they watched, it boiled up taller and taller into the sky, a plume twice as high as the mountain, leaning towards them like an evil genie. As afternoon approached, the traffic thinned. Each time a car drew up, the little ceremony was the same: the crowd's eyes switching to the new arrival, the overalled man slicing his throat, the moment of blankness and then comprehension, eyes turning away. Some of the drivers just stood there, looking accusingly at the petrol pumps; others got back into their cars and sat for a while with their hands on the steering wheels, waiting for something to come to them. One man started up his car again immediately and headed off, only to coast to a halt a few hundred metres down the drag. He didn't even bother to pull off on to the shoulder. Another car came in, pushed by three sweaty men. They left the vehicle standing in the road and came closer, exchanging brief words with the petrol attendants. Their forearms were pumped up from exertion and they stood for a while with their hands hanging at their sides. There was no traffic at all going into the city. Over the previous two days, TV news had shown pictures of the N1 and N2 jam- packed for fifty kilometres out of town. It had taken a day for most people to realise the seriousness of the explosion; then everybody who could get out had done so. Now, Lynn supposed, lack of petrol was trapping people in town. She herself had left it terribly late, despite all the warnings. It was typical; she struggled to get things together. The first night she'd got drunk with friends. They'd sat up late, rapt in front of the TV, watching the unfolding news. The second night, she'd done the same, by herself. On the morning of this the third day, she'd woken up with a burning in the back of her throat so horrible that she understood it was no hangover, and that she had to move. By then, everybody she knew had already left. People were growing fractious, splitting into tribes. The petrol attendants and the car- pushers stood around the taxi. The attendants' body language was ostentatiously off- duty: ignoring the crowd, poison Kenya Airways is proud of its association with The Caine Prize for African Writing, awarded annually for a short story by an African writer published in English. Henrietta Rose- Innes won the 2008- 9 competition with this story, Poison. on the morning of the third day she'd woken up with a burning in the back of her throat so horrible that she understood it was no hangover.