animal behaviour
edyong | March 27, 2009Termite colonies are families - millions of individual workers all descended from one king and one queen. But the colony itself tends to outlast this initial royal couple. When they die, new kings and queens rise to take their place. These secondary royals are a common feature of some families of termites, and they will often mate with each other for many generations. But there is more to this system than meets the eye.
Kenji Matsuura from Okayama University has found that the secondary queens are all genetically identical clones of the original. There are many copies, and they have no…
edyong | March 26, 2009On the 3rd of October, 2006, Nicolas Makris watched a quarter of a billion fish gather in the same place. They were Atlantic herring, one of the most abundant fishes in the ocean and one prone to gathering in massive schools. This was the first time that anyone had watched the full scope of the event, much less capture it on video.
The first signs of the amassing herring appeared around 5pm and by sunset, the gathering had begun in earnest. Once a critical level of fish was reached, the shoal expanded at a breakneck pace, suddenly growing to cover tens of kilometres within the hour. By…
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 | March 16, 2009Farmers and herders have known for centuries that herds of cattle have an uncanny ability to all point in the same direction. Last year, a group of German and Czech scientists discovered the reason behind this alignment - unbeknownst to humans for thousands of years of domestication, these animals have a magnetic sense. The team used Google Earth satellite images to rule out alternative explanations like the wind and the sun, and show that cow and deer herds tend to point towards magnetic north like a living, hoofed compass needle.
Now, the same team have found that high-voltage power lines…
edyong | March 13, 2009The songs of birds certainly sound beautiful to our ears but listen closely and you'll hear a world of conflict and subterfuge. Take the Preuvian warbling antbird (Hypocnemis peruviana). Males and females live in pairs and they will defend their territories from other duos by singing beautifully coordinated duets.
Theirs is a most melodious partnership but throw another female into the mix and the harmony breaks down. The duet turns into an acoustic battle - the female tries to jam the song of her partner with her own, so that the notes of his amorous solo fail to reach the ears of the…
edyong | March 10, 2009If you wanted to turn a rat into a fearless critter, unfazed by cats or bigger rats, the best way would be to neutralise a small pair of tiny structures in its brain called the dorsal premammillary nuclei, orPMD. According to new research by Simone Motta at the University of Sao Paolo, these small regions, nestled within a rat's hypothalamus, control its defensive instincts to both predators and other rats.
But not all neurons in the PMD are equal. It turns out that the structures are partitioned so that different bits respond to different threats. The front and side parts (the ventrolateral…
edyong | March 9, 2009
In 1997, Swedish inspectors found several stockpiles of missiles hidden in a local zoo. Apparently, the arsenal had been gathered together for the express purpose of being used against civilians. And who was the mastermind behind this collection? A 19-year-old chimpanzee called Santino.
Santino was born in a German zoo in 1978 and transferred to Furuvik Zoo at the age of 5. To this day, he lives in the zoo's chimpanzee island - a large outdoor enclosure surrounded by a moat. Throughout his residence, he was mostly docile towards the eager visitors, but all of that changed in 1997 when he…
edyong | March 8, 2009
Imagine that you're driving along a country lane. As often happens, the road suddenly transforms from a well-paved street to a pothole-ridden nightmare. As your suspension and your stomachs start to tire, your friends in the back suddenly force you to stop the car.
To your amazement, they jump out and lie across the potholes, beckoning you to drive your car over them. It may seem like a far-fetched scenario, but if you were an army ant, such selfless behaviour would be a matter of course.
Army ants are some of the deadliest hunters of South America. Amassing in legions of over 200,000 ants…
edyong | March 3, 2009In the Goualougo Triangle of the Republic of Congo, a chimpanzee is hungry for termites. Its prey lives within fortress-like nests, but the chimp knows how to infiltrate these. It plucks the stem from a nearby arrowroot plant and clips any leaves away with its teeth, leaving behind a trimmed, flexible stick that it uses to "fish" for termites.
Many chimps throughout Africa have learned to build these fishing-sticks. They insert them into termite nests as bait, and pull out any soldier termites that bite onto it. But the Goualougo chimps do something special. They deliberately fray the ends…
edyong | March 1, 2009If you've ever complained about having bad sex, you really have no idea. Human women may have to complain about poor stamina or incompetent technique but the female seed beetle (or bean weevil; Callosobruchus maculatus) has to contend with her partner's nightmarish penis - an organ covered in hard, sharp spikes. Just see if you can look at the picture on the right without wincing.
It's no surprise then that females sustain heavy injuries during sex. But why have male beetles evolved such hellish genitals? What benefits do they gain by physically harming their partners?
It's possible that…
edyong | February 25, 2009Imagine that a massive hole appeared in a wall of your house, and you'd decided to fix it yourself. You head over to a DIY store and load up on plaster, tools and paint and look forward to many hard and tedious hours of work. If that seems like a chore, you might get some perspective by considering the plight of the gall aphid Nipponaphis monzeni. When holes appear in their homes, some unlucky individuals are tasked with repairing the damage using their own bodily fluids. They sacrifice themselves for the sake of some DIY.
Some species of aphids are heading towards the incredibly cooperative…
neurophilosophy | February 10, 2009Bones have been big news recently, following the publication of two papers which document remarkable fossil finds. First, a group of palaeontologists led by Phil Gingerich of the University of Michigan described Maiacetus inuus, a primitive whale which lived in the water but gave birth on land, and which marks the transition between modern whales and their terrestrial ancestors. This was quickly followed by the report, from Jason Head's group at the University of Toronto, of Titanoboa cerrejonesis, a prehistoric snake which is estimated to have grown to 13 metres and to weigh more than a…
edyong | February 7, 2009A couple of weeks ago, I wrote about a dolphin that has mastered the trick of killing cuttlefish and elaborately preparing them for a meal. It was a great story that highlighted just how intelligent and versatile dolphins can be, but it was a bit of a bittersweet report. The cuttlefish didn't exactly come out of it very well, which is a shame - they are intelligent creatures in their own right, every bit as fascinating as dolphins are. So it's with great glee that I report a new study that should help to restore the cuttlefish's credibility and cement its position as one of the cleverer…
edyong | February 6, 2009Ants are among the most successful of living things. Their nests are well-defended fortresses, coordinated through complex communication systems involving touch and chemical signals. These strongholds are stocked with food and secure from the outside world, so they make a tempting prospect for any burglars that manage to break in.
One species of butterfly - the mountain alcon blue (Maculinea rebeli) - is just one such master felon. Somehow, it manipulates the workers into carrying it inside the nest, feeding it and caring for it. The caterpillar does so little for itself that it packs on 98…
edyong | February 2, 2009In the movie Finding Nemo, the eponymous clownfish grows up in the security of his home reef and must find his way back after being fry-napped by an overenthusiastic diver. In reality, the larvae of clownfish spend their early lives adrift in the open ocean and only after weeks, or possibly months, do they return to the reefs where they were born.
Their journey is guided by several cues that help them navigate home. The sound of a reef may be one of these but it's clear that the most important sense for a returning fish is smell. Young fish have very well developed smell organs and respond…
edyong | January 31, 2009
Hollywood cavemen typically communicate with grunts and snorts, reflecting a belief that human language originated like this and slowly evolved into the rich and sophisticated tongues we use today. But researchers from Emory University, Atlanta have found evidence that the origins of human language could lie in gestures, not words. If they are right, then high-fives, V-signs and thumbs-ups could more closely reflect the beginnings of human language than conversations do.
All primates can communicate with each other through facial expressions, body postures and calls, but humans and apes are…
edyong | January 29, 2009Serotonin is a chemical jack-of-all-trades. It relays messages between the cells of the brain and in doing so, controls everything from anger to sleep, body temperature to appetite. But in one insect, it is the key to Pandora's box, periodically unleashing some of the most destructive swarms on the planet. It is the chemical responsible for turning solitary desert locusts into massive plagues.
With desert locusts, you get two insects for the price of one. For most of their lives, they are positively antisocial and will avoid other locusts - a far cry from the devastating swarms that farmers…
jwhitfield | January 27, 2009Science is fun. Now, I know that someone telling you a thing is fun is usually a guarantee that it isn't. And I know that people who tell you science is fun usually do so in strained and pleading tones, and expect you to believe them because they have spiky hair and can play the harmonica. But it's true.
To see what I mean, read chapter 6 of the Origin, 'Instinct'. Despite, or because of, having its share of 'are you sure about that?' moments, it's a delight, because it shows Darwin doing the most fun thing in science: mucking about with reality, sometimes called experimentation.
In this…
edyong | January 21, 2009If the sound of eating dung all your life doesn't sound that appealing to you, you're not alone. A beetle called Deltochilum valgum shares your distaste, which is quite surprising given that it's a dung beetle.
There are over 5,000 species of dung beetle and almost all of them feed mainly on the droppings of other animals (and more specifically, on the rich supply of bacteria they contain). D.valgum is the black sheep of the family, the only one that has abandoned the manure-based diet of its fellows and taken to hunting live meat for a living.
D.valgum lives in the lowland rainforests of…
edyong | January 17, 2009
Bee hives, with their regularly arranged honeycombs and permanently busy workers may seem like the picture of order. But look closer, and hives are often abuzz with secret codes, eavesdropping spies and deadly alliances.
African honeybees are victimised by the parasitic small hive beetle. The beetles move through beehives eating combs, stealing honey and generally making a mess. But at worst, they are a minor pest, for the bees have a way of dealing with them.
They imprison the intruders in the bowels of the hive and carefully remove any eggs they find. In turn, the beetle sometimes fools…