animal behaviour
edyong | January 15, 2009From the carpenter choosing the right strength of drill, or the artist selecting the right weight of pencil, humans have a natural talent for picking the right tool for the job. Now, it seems that monkeys are similarly selective about their tools. In the first study of its kind, Elisabetta Visalberghi from the National Research Council, Italy, found that capuchin monkeys are able to pick stones with the right properties for nutcracking.
Capuchins often use stones to crack otherwise impenetrable nuts upon hard, flat surfaces, turning innocuous forest objects into their own hammers and anvils…
edyong | January 9, 2009To our ears, the buzz of a mosquito is intensely irritating and a sign of itchiness to come, but to theirs, it's a lover's serenade. The high-pitched drone of a female is a siren's song that attracts male mosquitoes. And a new study shows that when the two love-bugs meet, they perform a duet, matching each other's buzzing frequency with careful precision.
The female Aedes aegypti mosquito (the carrier of both dengue and yellow fever) beats her wings with a fundamental frequency of about 400Hz, producing a pitch just slightly lower than concert A. Males on the other hand, have a fundamental…
neurophilosophy | January 9, 2009The familiar buzzing sound made by a mosquito may be irritating to us humans, but it is an important mating signal. The sound, produced by the beats of the insect's wings, has a characteristic frequency called the "flight tone"; when produced by a female, it signals her presence to nearby males, thereby attracting potential mates.
Attraction is not simply a matter of the male hearing and homing in on the female's flight tone. Females were long believed to be deaf, but two years ago, it was found that courting pairs interact acoustically to create a duet: both male and female modulate the…
edyong | December 29, 2008On the fifth day of this year, I found myself sitting in the living room of the legendary Sir David Attenborough, drinking coffee and talking to him about wildlife, filmmaking and his career for the better part of an hour. It was a truly memorable experience, not just for his eloquence and storytelling skills, but because Sir David has been a hero of mine since I first popped Life on Earth into my VCR at the wee age of 8. His clarity and passion have inspired me to become a better communicator of science and it was a privilege to speak to the man in person.
He was no less of a superb…
edyong | December 22, 2008The relationship between bees and plants is one of the most well-known in the natural world. Almost everyone knows that bees carry pollen from plant to plant and receive a rewarding sip of sugary nectar in return. Surely there are few sides to this most familiar of alliances left to discover?
Not so. Jurgen Tautz and Michael Rostas from the University of Wuerzburg have found that bees provide another service to flowers, besides acting as a pollen vehicle - they deliver a protection service for their very buzzing scares away hungry caterpillars.
In their University's botanical garden, they…
edyong | December 18, 2008In 1995, a palaeontologist called Mark Norrell reported an amazing discovery - the fossilised remains of a dinosaur called Troodon, sitting on top of a large clutch of eggs. The fossil was so well-preserved and its posture so unmistakeable that it provided strong proof that some dinosaurs incubated their eggs just as modern birds do. And since then, two other small predatory species - Oviraptor and Citipati - have been found in brooding positions on top of egg clutches.
But a subtler look at these fossils reveal much more about dinosaur parenting than the simple fact that it existed. To…
edyong | December 15, 2008 In Shark Bay, off the Western coast of Australia, a unique population of bottlenose dolphins have a unusual trick up their flippers. Some of the females have learned to use sponges in their search for food, holding them on the ends of their snouts as they rummage through the ocean floor.
To Janet Mann at Georgetown University, the sponging dolphins provided an excellent opportunity to study how wild animals use tools. Sponging is a very special case of tool use - it is unique to Shark Bay's dolphins and even there, only about one in nine individuals do it. The vast majority of them are…
edyong | December 11, 2008Moving to a new area can be a daunting experience, especially if you don't know anyone. At first, you might cling to any friends who do live nearby but eventually, you meet new people and start to integrate. As it is with humans, so it is with elephants.
Noa Pinter-Wollman and colleagues from the University of California, Davis wanted to study how African elephants behave when they move to new environments. This happens quite naturally as elephants live in dynamic societies where small family groups continuously merge with, and separate from, each other. But they also face new territories…
edyong | December 10, 2008Pity the small fish snagged by a sea anemone. Blundering into the waving tentacles, the fish is stung by hundreds of tiny harpoons shot out from stinging cells, each one loaded with potent venom. It is paralysed and moved towards the anemone's 'mouth', which lies in the centre of its tentacles and also doubles as its anus. The fish is swallowed and , but its ignominious fate doesn't end there. The anemone's internal cavity (which passes for its stomach) is also lined with thousands of stinging cells so that even after it's been swallowed, the fish continues to be stung.
The sea anemone is a…
edyong | December 9, 2008If a colleague of yours was rewarded for their work while you received nothing for your (similarly sized) efforts, you would probably be quite peeved. Now it seems that man's best friend also shares our disdain for unfairness.
Humans are notorious for our dislike of injustice. It rankles us to see others being rewarded or penalised unfairly. We not only have the capacity to recognise when someone else is being rewarded beyond their efforts, but the inclination to punish them for it, often at personal expense. But other species behave in the same way - recent studies have found that capuchin…
edyong | November 16, 2008
Many naturalists become so familiar with the animals they study that they can recognise individuals within a population using just their shapes and patterns. If that's too difficult, animals can be ringed or tagged. These tricks give scientists the invaluable ability to track the fates of individuals, but try using them on octopuses.
Recognising shape and pattern is impossible when your subject has the ability to change the texture and colour of its already pliant body on a whim. Injured individuals are distinctive enough, but only for a short while before their remarkable healing abilities…
neurophilosophy | November 11, 2008Every autumn, millions of songbirds embark upon long distance southerly migrations to warmer climes. Some species migrate during the day, but the majority - including sparrows, thrushes and warblers - do so at night, leaving their daytime habitats just after dusk and spending the next 8-10 hours on the wing.
Nocturnal migration has several benefits. Cooler temperatures reduce the risk of overheating; reduced turbulence allows for a smooth flight with minimal energy expenditure; and the cover of night provides good protection from predators. These fly-by-night migratory species lose…
edyong | November 4, 2008You are the alpha male, the top dog, the grand kahuna. A young upstart is trying to muscle his way onto your turf and compete for your women. Your solution - click your knees loudly at him. It seems like a strange strategy. For humans, a clicking knee would hardly be a sign of strength but it's all part of the bizarre communications of the world's largest antelope - the eland.
Elands bulls have a strict pecking order that determines their access to females in the herd. On the few occasions when they fight, they hardly ever use their dangerous horns and hooves, preferring instead to prove…
edyong | October 25, 2008
Animals often show a keen intelligence and many species, from octopuses to crows, can perform problem-solving tasks. But humans are thought to go one step further. We can reflect on our own thoughts and we have knowledge about our knowledge. We can not only solve problems, but we know in advance if we can (or are likely to).
In technical terms, this ability is known as 'metacognition'. It's what students do when they predict how well they will do in an exam when they see the questions. It's what builders do when they work out how long a job will take them to finish. But can animals do…
neurophilosophy | October 22, 2008The fourth dimension - time - is essential for many cognitive processes, and for rhythmic movements such as walking. Recent research has begun to elucidate how neuronal activity encodes events that occur on the timescale of tens to hundredths of milliseconds (hundredths of a second) and contain cues which are required for processes such as visual perception, speech discrimination and fine movements.
Many organisms time events on much larger scales. However, next to nothing is known about the mechanisms by which the brain encodes longer periods of time. A new study now sheds some light on…
edyong | October 22, 2008
Humans are a funny lot. While we seem to be relentless voyeurs, we generally frown on eavesdropping as an invasion of privacy. But in the animal world, eavesdropping can be a matter of life or death. Animals rarely communicate in isolation. Often it pays for one species to monitor the dialogues of others, particularly when predator warnings are involved.
Small animals in particular do well to pay attention to the alarms of other species, as they are often preyed upon by the same larger hunters. Even very unrelated species can listen in and understand each other's signals. Vervet monkeys…
neurophilosophy | October 20, 2008When confronted with threatening stimuli and predators, the crayfish responds with an innate escape machanism called the startle reflex. Also known as tailflipping, this stereotyped behaviour involves rapid flexions of the abdominal muscles which produce powerful swimming strokes that thrust the small crustacean through the water and away from danger. In the struggle for existence, the speed of this response can mean the difference between life and death, and the crayfish has evolved an incredibly fast escape mechanism which can be initiated within well under one-hundredth of a second.…
edyong | October 20, 2008
Moving robots are becoming more and more advanced, from Honda's astronaut-like Asimo to the dancing Robo Sapien, a perennial favourite of Christmas stockings. But these advances are still fairly superficial. Most robots still move using pre-defined programmes and making a single robot switch between very different movements, such as walking or swimming, is very difficult. Each movement type would require significant programming effort.
Robotics engineers are now looking to nature for inspiration. Animals, of course, are capable of a multitude of different styles of movement. They have…
edyong | October 17, 2008
In the Ivory Coast, a small stream called Audrenisrou winds its way through the lowland rainforest of the Tai National Park. On the floodplain of this stream, at a site called Nuolo, lie several stones that seem unassuming at first glance. But to the trained eye, they are a window to the past.
Their shape is different to other stones that have been worn away by natural erosion. They have been flaked in systematic ways and many are flattened and sharp. Clearly, they were shaped by hand for a purpose - they are tools. Their creators were not humans, but close relatives who lived in these…
edyong | October 16, 2008Looking at Britain's overcrowded prisons, Wembley stadium or the continual dithering over solid climate change policies, it would seem that many of us are really quite bad at planning for the future. Even so, most of us can still do it (even though some may do it very badly). This abilty isn't there from birth; children only develop a sense of a future at the age of two and they can only plan for it from four or five. But eventually, everyone picks up the skill and up till recently, scientists believed that we were the only species that did.
Many animals show behaviour that could be…