Animal locomotion
edyong | January 28, 2010
When our lives are in danger, some humans go on the run, seeking refuge in other countries far away from the threats of home. Animals too migrate to escape danger but one group - the pond-living bdelloid rotifers - have taken this game of hide-and-seek to an extreme.
If they are threatened by parasitic fungi, they completely remove any trace of water in their bodies, drying themselves out to a degree that their parasites can't stand. In this desiccated state, they ride the wind to safety, seeking fresh pastures where they can establish new populations free of any parasites.
This…
edyong | January 14, 2010
I've just flown from London to North Carolina, a trip of around 6,200km. As flights go, it's a pathetic one, a mere jaunt in the park compared to the epic voyage of the Arctic tern. Every year, this greatest of animal travellers makes a 70,000 km round-trip, in a relentless, globe-trotting pursuit of daylight. In summer, it spends its time in the sun-soaked Arctic and in winter, it heads for the equally bright climes of Antarctica. In its 30 years of life, this champion aeronaut flies more than 2.4 million kilometres - the equivalent of three return journeys to the Moon.
The Arctic tern'…
edyong | December 14, 2009
Octopuses are masters of camouflage that can change their shape, colour and texture to perfectly blend into their environment. But the soft bodies that make them such excellent con artists also make them incredibly vulnerable, should they be spotted. Some species have solved that problem with their fierce intellect, which allows them to make use of other materials that are much harder. The veined octopus, for example, dons a suit of armour made of coconut shells.
The veined octopus (Amphioctus marginatus) lives in sandy, exposed habitats that have little in the way of cover. To protect…
edyong | September 8, 2009When danger threatens many lizards can detach their tails, leaving them behind as decoys in the hope that the predator will attack it rather than the lizard itself. But the tail doesn't just lie there as bait. For half an hour after they've been severed, the disembodied tails perform a complex dance, flipping, lunging and jumping up to an inch in the air. These acrobatics serve to distract the predator even further.
For the first time, Timothy Higham and Anthony Russell have studied the movements of severed gecko tails to understand how they can move in such complex ways without any input…
edyong | August 18, 2009Several million years ago, at a time when dinosaurs walked the earth, a flying reptile - a pterosaur - came in for a landing. As it approached, it used its powerful wings to slow itself down and hit the ground feet first. It took a short hopping step before landing a second time. On solid ground, it leant forward, put its arms down and walked away on all fours.
The landing made quite an impression on the underlying limestone mud and in the following millennia, the creature's tracks became fossilised. Now, they have been unearthed by Jean-Michel Mazin from the University of Lyon at a site…
edyong | May 31, 2009
Six million years ago, the skies of Argentina were home to fearsome predator - Argentavis magnificens, the largest bird to ever take to the air. It weighed in at 70kg and had a wingspan of 7m, about the same size as a Cessna 152 light aircraft.
Argentavis was a member of an extinct group of predatory birds understandably called the teratorns - 'monster birds'. They are related to storks and New World vultures such as turkey vultures and condors. But Argentavis completely dwarfed even the massive Andean condor, weighing six times more and with a wingspan over twice as long (in the picture…
edyong | April 30, 2009Snowball, the sulphur-crested cockatoo, is an internet superstar. He's known for his penchant for grooving to music, notably Everybody by the Backstreet Boys. As the music plays, Snowball bobs his head and taps his feet in perfect time with it. If it speeds up or slows down, his rhythm does too. He is one of two parrots that are leading a dance dance revolution, by showing that the human behaviour of moving in time to music (even really, really bad music) is one that's shared by other animals.
People who've attended parties at scientific events may question the ability of humans to move to a…
edyong | April 21, 2009For long journeys, the shell of a snail hardly seems like the ideal public transport. That is, of course, unless you're an even smaller snail...
Yasunori Kano from the University of Miyazaki has found that the babies of Neritina asperulata, a tiny snail just 3 millimetres across, hitchhike on the back of a larger species Neritina pulligera. This living bus is about 2 centimetres long, and dwarfs its passengers by more than seven times.
The hitchhiking snail is a special sort of parasite, and one that Kano thinks has never been described before. They don't use their hosts as a snack, a home…
edyong | April 20, 2009
Studying the way an animal moves by looking at its ears might seem like a poorly thought-out strategy. After all, short of watching it directly, most biologists would choose to look at more obvious traits like tracks, or limb bones.
But while an animal's limbs may drive it forward, its inner ear makes sure that it doesn't immediately fall over. By controlling balance, it plays a key role in movement, and its relative size can tell us about how agile an animal is.
When we walk, the image that forms on our retinas changes quite considerably. But no matter how fast or erratically we move,…
edyong | March 21, 2009
Walking on two legs, or bipedalism, immediately sets us apart form other apes. It frees our arms for using tools and weapons and is a key part of our evolutionary success. Scientists have put forward a few theories to explain how our upright gait evolved, but the 'savannah theory' is by far the most prolific.
It's nicely illustrated by this misleading image that has become a mainstay of popular culture. It suggests that our ancestors went from four legs to two via the four-legged knuckle-walking gait of gorillas and chimps. Dwindling forests eventually pushed them from knuckle-walking to a…
edyong | February 13, 2009In the summer of 2007, thirty-four travellers left home with backpacks in tow to see the world. But these weren't human students, out to get drunk and pretentious find themselves in foreign lands - they were small songbirds, migrating to tropical climates for the winter.
Their backpacks were light-measuring devices called "geolocators", each about the size of a small coin. By measuring rising and falling light levels, these miniature contraptions revealed the timings of sunrise and sunset wherever the birds happened to be flying. Those, in turn, revealed where they were in the world, and…
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 | July 12, 2008
There is an old joke that if Spider-Man has the powers of a spider, he really ought to be shooting webs from somewhere less salubrious than his hands. In the films and comic books, Peter Parker is empowered with the powers of a human-sized arachnid through a spider bite. He effortlessly scales walls and ceilings and shoots sticky webs from his wrists. Now, scientists have found a type of spider that does just that.
Like Spider-Man, most spiders can climb sheer surfaces and they do so with two techniques. The most obvious are small claws, called tarsi, that grip onto rough surfaces.…
edyong | June 13, 2008Many groups of animals, from humans to dinosaurs to kangaroos, have evolved the ability to stand and walk on two legs. In all of these cases, the move from four legs to two has provided clear advantages. Kangaroos save energy because their hopping is so efficient, birds have freed their front pair of limbs for use as wings, and humans use ours for manipulating tools and objects.
But some species of lizards also rear up on their hind legs from time to time, particularly when running. The Australian frilled lizard does it so readily that it has earned the nickname of 'bicycle lizard'. And the…
edyong | June 5, 2008
On Wednesday, I posted about a parasitic wasp that turns a caterpillar into both a living incubator and a zombie-like bodyguard for its larvae. Well, it seems to be a bumper week for wasp research; today, we have yet another demonstration of the amazing tactics used by these macabre parents to provision their young with food.
The stunning colours of the jewel wasp (Ampulex compressa) belie its gruesome habits. Its grubs feed on the bodies of cockroaches supplied by their mother. When a female wasp finds a roach, she stings it twice - once in its mid-section to immobilise its front…
edyong | May 15, 2008Hi folks,
I'm working on a large feature and I want to break the back of it over the weekend. So as a ittle bit diversion, I wanted to share with you two awesome videos that I took last weekend of gibbons moving with characteristic and incredible agility at Thrigby Hall Wildlife Gardens in Suffolk. Gibbons were one of the highlights of David Attenborough's Life of Mammals, and I was utterly captivated by footage of them monkeyi... er.. apeing about in trees, swinging through the canopy at high speed. (There's a second video and some commentary after the jump)
This style of movement, known…
edyong | May 8, 2008
A tenth of the planet's population occasionally suffers through devastating famines because small insects fear being bitten in the bum. That's the astonishing message from a new study of one of mankind's greatest pests - the desert locust.
Swarms can stretch for several hundred square kilometres and each of these harbours up to 80 million hungry sets of mandibles that eat their own body weight in food every day. These plagues are unpredictable but they only form when locust populations reach some sort of critical mass. Desert locusts are two insects for the price of one; at a crowded…
edyong | March 17, 2008
Geckos are nature's champion climbers. With remarkable ease, they can scamper across ceilings and up smooth vertical surfaces, and they do so at speed. A vertically running gecko can cover 15 times the length of its body in a single second. So far, scientists have focused their attention on the gecko's amazingly adhesive feet but a new study demonstrates the importance of a neglected piece of their climbing gear - their tails. Geckos use their tails to stop themselves from falling, and to land safely if they do.
A gecko's foot is a marvel of biological engineering. Rather than relying on…