Animal communication
edyong | February 25, 2010Take a look at these two fish. At first glance, they seem incredibly similar but in fact, they belong to two separate species. The one on the top is an Ambon damselfish (Pomacentrus amboinensis) and the one on the bottom is a lemon damselfish (P.moluccensis). If the distinction is hard for us to grasp, it's because we're not looking with the right eyes. The fish have a secret communication channel that's hidden to us. To hack into it, we need to look at the fish under an ultraviolet lamp.
The glare of a UV light reveals that the even yellow colours of the damselfishes' faces are actually…
edyong | February 11, 2010Bees can communicate with each other using the famous "waggle dance". With special figure-of-eight gyrations, they can accurately tell other hive-mates about the location of nectar sources. Karl von Frisch translated the waggle dance decades ago but it's just a small part of bee communication. As well as signals that tell their sisters where to find food, bees have a stop signal that silences dancers who are advertising dangerous locations.
The signal is a brief vibration at a frequency of 380 Hz (roughly middle G), that lasts just 150 milliseconds. It's not delivered very gracefully.…
edyong | December 7, 2009Many human languages achieve great diversity by combining basic words into compound ones - German is a classic example of this. We're not the only species that does this. Campbell's monkeys have just six basic types of calls but they have combined them into one of the richest and most sophisticated of animal vocabularies.
By chaining calls together in ways that drastically alter their meaning, they can communicate to each other about other falling trees, rival groups, harmless animals and potential threats. They can signal the presence of an unspecified threat, a leopard or an eagle, and…
edyong | September 26, 2009This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science. The blog is on holiday until the start of October, when I'll return with fresh material.
In your garden, there's a fair chance that a farmer is currently tranquilising her livestock with a chemical cocktail she secretes from her feet. Don't believe me? Look closer...
Humans aren't the only species that farms other animals for food - ants do it too and their herds consist of aphids. They feed on plant sap and excrete a sweet and nutritious liquid called honeydew, which the ants drink.
In…
edyong | September 4, 2009Domestic dogs are very different from their wolf ancestors in their bodies and their behaviour. They're more docile for a start. But man's best friend has also evolved a curious sensitivity to our communication signals - a mental ability that sets them apart from wolves and that parallels the behaviour of human infants. Dogs and infants are even prone to making the same mistakes of perception.
Like infants less than a year old, dogs fail at a seemingly easy exercise called the "object permanence task". It goes like this: if you hide an object somewhere(say a ball under a cup) and let the…
edyong | September 2, 2009Birds have a variety of alarm calls that warn other members of the flock about impending danger. But for some birds, the very act of taking off is enough to sound the alarm. Mae Hingee and Robert Magrath from the Australian National University have found that crested pigeons have modified wing feathers that produce distinct whistles when the birds take off quickly and steeply. That's exactly the sort of flight that they undertake when they're alarmed, and other pigeons treat the resulting whistles as cues to take to the skies themselves.
Crested pigeons are comical-looking birds that are…
edyong | August 17, 2009In a Swiss laboratory, a group of ten robots is competing for food. Prowling around a small arena, the machines are part of an innovative study looking at the evolution of communication, from engineers Sara Mitri and Dario Floreano and evolutionary biologist Laurent Keller.
They programmed robots with the task of finding a "food source" indicated by a light-coloured ring at one end of the arena, which they could "see" at close range with downward-facing sensors. The other end of the arena, labelled with a darker ring was "poisoned". The bots get points based on how much time they spend near…
edyong | August 13, 2009They say that imitation is the sincerest form of flattery and it appears that capuchins believe it too. These very sociable monkeys gravitate towards humans that mimic their actions, spending more time in their company and even preferring to trade with them.
Annika Paukner, who studied this monkey business, thinks that imitation is a type of social glue that binds groups of monkeys together. It says, "We are alike," and in doing so, it lays the foundation for acts of selflessness by providing a means for two individuals to form an empathic connection.
Certainly, imitation is very much a…
edyong | August 4, 2009You'll sometimes hear people lowering their voices to make themselves sound tougher or more commanding. We're not the only ones - it seems that our close relatives, the orang-utans, pull the same trick, and they use tools to do it. Madeleine Hardus from the University of Utrecht has found preliminary evidence that young orang-utans use leaves for deception, in order to make lower-pitched calls that seem to come from a much larger animal.
While many animals are accomplished tool-users, most use their utensils to find food. A few populations of orang-utans, living in Borneo, are the only…
edyong | July 13, 2009While dogs can often be taught new tricks, cat-owners will be all too aware that it can be very difficult to persuade them to do something they don't want to do. Eddie Izzard summed it up best in his legendary Pavlov's cat sketch, where felines are quite capable of outfoxing (outcatting?) eminent Welsh-Russian psychologists. Real cats may be less devious, but only just - new research suggests that they are very skilled at getting their human owners to do their bidding.
When they want food, domestic cats will often purr in a strangely plaintive way that their owners find difficult to ignore…
edyong | June 4, 2009 If you tickle a young chimp, gorilla or orang-utan, it will hoot, holler and pant in a way that would strongly remind you of human laughter. The sounds are very different - chimp laughter, for example, is breathier than ours, faster and bereft of vowel sounds ("ha" or "hee"). Listen to a recording and you wouldn't identify it as laughter - it's more like a handsaw cutting wood.
But in context, the resemblance to human laughter is uncanny. Apes make these noises during play or when tickled, and they're accompanied by distinctive open-mouthed "play faces". Darwin himself noted the laugh-like…
edyong | May 6, 2009We recognise dead people by the absence of signals that indicate life - movement, responsiveness, pulses, brain activity, and so on. The Argentine ant does the same, but its signal is a chemical one. Throughout its life, an ant uses chemicals in its skin to automatically send out a message to its nest-mates, saying "I'm alive. Don't throw me out." When it dies, these "chemicals of life" fade away, and their bodies are evicted.
Social insects like ants and honeybees are fastidious about their colony's tidiness. If any individuals die, they're quickly removed and thrown away in one of the…
edyong | May 2, 2009
Impressionists are a mainstay of British comedy, with the likes of Rory Bremner and Alistair MacGowan uncannily mimicking the voices of celebrities and politicians. Now, biologists have found that tiger moths impersonate each other too, and they do so to avoid the jaws of bats.
Some creatures like starlings and lyrebirds are accomplished impersonators but until now, we only had anecdotal evidence that animals mimic each others' sounds for defence. Some harmless droneflies may sound like stinging honeybees, while burrowing owls deter predators from their burrows by mimicking the distinctive…
edyong | April 15, 2009Autumn is a time of incredible beauty, when the world becomes painted in the red, orange and yelllow palette of falling leaves. But there may be a deeper purpose to these colours, and the red ones in particular. In the eyes of some scientists, they aren't just decay made pretty - they are a tree's way of communicating with aphids and other insects that would make a meal of it. The message is simple: "I am strong. Don't try it."
During winter, trees withdraw the green chlorophyll from their leaves, and textbooks typically say that autumn colours are produced by the pigments that are left…
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 | 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 | 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 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…
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…
grrlscientist | December 1, 2008tags: animal cognition, animal communication, animal behavior, birds, parrots, Alex and me, Irene Pepperberg, book review
He was not ours, he was not mine.
Thank you for sharing him with us.
He brought us much joy. We loved him well.
-- Irene Pepperberg (p. 226), modified from Karen Blixen's
eulogy for Denys Finch-Hatton in Out of Africa.
As a scientist who studies, lives with, and even breeds and hand-feeds parrots, it is easy for me to empathize with Irene Pepperberg, the author of the long-awaited book with the awkward title, Alex and Me: How a Scientist and a Parrot Uncovered a Hidden…