animal behaviour
edyong | October 15, 2008
It is midday in Senegal and a chimpanzee is on the hunt. Its target is a bushbaby, a small, cute and nocturnal primate that spends its days sheltered in the hollow of a tree, beyond the reach of predators like the chimp. But this hunter is not like others - it is intelligent, it is dextrous, and it has a plan. Snapping off a thin branch, the chimp strips it of twigs, leaves and bark. And with its teeth, it sharpens the tip into a murderous point.
It forcefully jabs its newly fashioned spear into the bushbaby's hiding place, stabbing the hapless animal multiple times. The chimp breaks…
edyong | October 13, 2008
Many animals use poisonous secretions to protect themselves from predators. But poisons are complex chemicals and can take a lot of energy to make. Why invest in them, when you can steal someone else's?
Poison thieves are well-known in the animal kingdom. Many species of brightly coloured poison arrow frogs acquire their poisons from beetles, while some sea slugs make a living by hunting for jellyfish, transporting their stinging cells into their own limbs. Now, another species joins this guild of thieves - the tiger keelback snake, Rhabdophis tigrinis (image right, by Deborah…
edyong | October 4, 2008
Sniffing brings molecules in the air around us into our nose, where they are detected and manifested in our brains as smells. But try the same trick underwater and you would rapidly choke or drown. Nonetheless, smell is a tremendously important sense for most mammals and at least two species have found a way to safely sniff in water.
The star-nosed mole (Condylura cristata) is one of them and it has one of nature's most unusual noses. Its snout ends in a ring of 22 fleshy tentacles that are loaded with touch sensors. With this nasal star, the mole rapidly touches and assesses its world,…
edyong | September 29, 2008
Two strangers are having a normal conversation in the middle of a large crowd. No one else can see them. No one else can listen in. Thanks to advanced gadgetry, they are talking in coded messages that only they can decipher. These invisible conversationalists sound like they've walked out of a Bond film. But they are entirely real, and their skill at secrecy is biological, not technological. They are squid.
Squid and their relatives, the octopus and cuttlefish, are masters of concealment. They have the most sophisticated camouflage abilities in the animal kingdom and use them to avoid…
edyong | September 28, 2008
You are on a date and by all accounts, it's going well. Midway through dinner, you excuse yourself and head to the bathroom where, to your chagrin, the mirror reveals that you have a streak of sauce on the side of your face. Embarrassed, you wipe it away and rejoin your date.
It's a fairly innocuous scene but it requires an ability that only the most intelligent of animals possess - self-awareness. It's the understanding that you exist as an individual, separate from others. Having it is a vital step to understanding that others are similarly aware and have their own thoughts and desires…
edyong | September 24, 2008A caterpillar is an eating machine - a mobile set of mandibles, whose sole mission is to survive long enough to munch its way to adulthood. Standing in their way are spiders, birds and predatory insects that want to eat them, and parasitic wasps that want to convert them into living incubators for their own larvae.
With so many enemies, defence is paramount for caterpillars and the various species have evolved a dazzling array of countermeasures. Some camouflage themselves, others use bright colours to advertise their toxic chemical weapons, which in at least one species is powerful enough…
edyong | September 10, 2008The forests of east Asia are home to giant honeybees. Each one is about an inch in length and together, they can build nests that measure a few metres across. The bees have an aggressive temperament and a reputation for being among the most dangerous of stinging insects. Within mere seconds, they can mobilise a swarm of aggressive defenders to repel marauding birds or mammals. But against wasps, they use a subtler and altogether more surprising defence - they do a Mexican wave.
Wasps, and hornets in particular, are major predators of bees and the largest ones can make even the giant bees…
edyong | August 27, 2008 Yesterday, I wrote about selfless capuchin monkeys, who find personal reward in the act of giving other monkeys. The results seemed to demonstrate that monkeys are sensitive to the welfare of their peers, and will make choices that benefit others without any material gain for themselves. Today, another study looks at the same processes in a very different sort of cheeky monkey - human children.
Humans are notable among other animals for our vast capacity for cooperation and empathy. Our concern about the experiences of other people, and our natural aversion to unfair play are the bedrocks…
edyong | August 26, 2008There are some who say that helping others is its own reward, and many biologists would agree. The fact that selfless acts give us a warm glow is evident from personal experience and neurological studies, which find that good deeds trigger activity in parts of the brain involved in feelings of reward. But feeling food by being good isn't just the province of humans - monkeys too get a kick out of the simple act of giving to their fellow simians.
At the Yerkes National Primate Research Center, Frans de Waal's team of scientists have been investigating the selfless side of eight brown capuchin…
edyong | August 25, 2008For centuries, farmers have known that their livestock not only gather in large herds but also tend to face the same way when grazing. Experience and folk wisdom offer several possible reasons for this mutual alignment. They stand perpendicularly to the sun's rays in the cool morning to absorb heat through their large flanks, or they stand in the direction of strong winds to avoid being unduly buffeted and chilled.
But cows and sheep don't just line up during chilly spells or high wind. Their motivations for doing so during warm, pleasant and unremarkable weather, or indeed in the dead of…
neurophilosophy | August 23, 2008NEARLY 70 years ago, Karl von Frisch described the alarm response in a species of small freshwater fish called the European minnow (Phoxinus phoxinus). Frisch, who was one of the founders ethology - the scientific study of animal behaviour - demonstrated that when a minnow was eaten by a predator, a chemical released from its damaged skin elicited defensive behaviour in other minnows that were close by. In response to the chemical, they would at first dart about randomly, form a tight school and then retreat from the source of the chemical.
Frisch called this substance schreckstoff, meaning…
edyong | August 20, 2008Owls may be are known for their trademark hooting noises, but a new study shows that they don't just rely on sound for communication. With some species having very large and sensitive eyes, you might expect that they would use visual signals too and that's exactly what a pair of Spanish biologists have found. Vincenzo Penteriani and Maria del Mar Delgado studied the eagle owl, and found that it marks its territories by recycling its meals - in more ways than one.
The eagle owl is the world's largest and is found in mountains and hilly forests throughout Europe and Asia. As breeding pairs…
neurophilosophy | August 19, 2008Self-recognition was long believed to be unique to humans. However, it was established more than 30 years ago that the great apes are capable of recognizing themselves in the mirror, and more recently it has been found that dolphins and elephants can too.
Now Prior et al provide the first evidence of mirror self-recognition in a non-mammalian species. In this film clip from the supplementary materials which accompany the paper, a magpie (which is actually a female) realizes that it has a mark on the side of its head after seeing its relection in the mirror. It then removes the mark by…
edyong | August 6, 2008Dogs may be known for their skills at catching sticks, but new research shows that are just as adept at catching our yawns. The result probably comes as no surprise to dog-owners but it's the first time that it's ever been demonstrated under experimental conditions.
Yawning is famously contagious - if one person does it, the chances are that someone nearby will start too. A variety of back-boned animals yawn, but until now only three species are known to catch them from each other - humans, chimps and stumptail macaques. The new study provides the first evidence that yawns can be contagious…
edyong | August 5, 2008Thanks to Hollywood, the jaws of the great white shark may be the most famous in the animal kingdom. But despite its presence in film posters, the great white's toothy mouth has received very little experimental attention. Now, Stephen Wroe from the University of New South Wales has put the great white's skull through a digital crash-test, to work out just how powerful its bite was.
A medium-sized great white, 2.5m in length and weighing in at 240kg, could bite with a force of 0.3 tonnes. But the largest individuals can exert a massive 1.8 tonnes with their jaws, giving them one of the most…
edyong | July 31, 2008They say that all's fair in love and war, and that certainly seems to be the case of Atlantic mollies (Poecilia mexicana). These freshwater fish are small and unassuming, but in their quest to find the best mates, they rely on and Machiavellian misdirection.
The males always prefer larger females but not if they are being watched. Under the voyeuristic gaze of a rival male, Atlantic mollies will either feign disinterest or direct their attentions toward a smaller, less attractive female.
Deception is par for the course in the animal kingdom. Plovers will try to lure predators away from…
edyong | July 29, 2008Imagine being able to drink ludicrous amounts of alcohol without getting drunk and without the nasty consequences in the morning. For some people, it would be a dream come true but for the pen-tailed treeshrew (Ptilocercus lowii), it's just part of everyday life.
The treeshrew lives in the rainforests of Malaysia and its local drinking establishment is a large plant called the bertam palm. The palm develops large stems a few metres in length, each of which sprouts about a thousand flowers. These are loaded with an alcoholic nectar with a maximum alcohol concentration of 3.8% - as strong as…
edyong | July 26, 2008
In a (very) loose tie-in with the recent release of the Dark Knight, it's Bat Weekend at Not Exactly Rocket Science, where I'll be reposting a few old but relevant pieces. If you were a biologist looking for astounding innovations in nature, you could do much worse than to study bats. They are like showcases of nature's ingenuity, possessing a massive variety of incredible adaptations that allow them to exploit the skies of the night.
They are the only mammal group capable of true flight and are one of only four groups of animals to have ever evolved the ability. As a result, they have…
edyong | July 21, 2008
Social spiders are an arachnophobe's nightmare. While the vast majority of spiders work alone, the odd few live communally and cooperate to hunt and feed. Their numbers, along with the massive webs that they all have a spinneret in creating, allow them to tackle prey far larger than themselves. The aftermath of a kill opens up new conflicts for the spiders that other cooperating hunters like lions or wolves don't share. They don't divide up the carcass to eat separately, for like all spiders, they digest their prey outside their bodies.
All the colony members spit their digestive enzymes…
edyong | July 19, 2008
In April 1998, an aggressive creature named Tyson smashed through the quarter-inch-thick glass wall of his cell. He was soon subdued by nervous attendants and moved to a more secure facility in Great Yarmouth. Unlike his heavyweight namesake, Tyson was only four inches long. But scientists have recently found that Tyson, like all his kin, can throw one of the fastest and most powerful punches in nature. He was a mantis shrimp.
Mantis shrimps are aggressive relatives of crabs and lobsters and prey upon other animals by crippling them with devastating jabs. Their secret weapons are a pair…