animal behaviour
neurophilosophy | December 15, 2007The film clip below shows a pack of killer whales co-operating to catch a seal. First, they break up the ice floe on which their prey is standing, and push it out into open water. Then, they create large waves to knock the seal into the water.
This kind of behaviour has been observed in killer whales before, and is apparently passed on from one generation to the next.
Read more at Nature News.
neurophilosophy | December 3, 2007
Researchers from Kyoto University's Primate Research Institute report that a young chimp can out-perform university students on a working memory task. (Cognitive psychologists use the term working memory to refer to the temporary storage and manipulation of information.)
The researchers developed a memory test called the limited-hold memory task in order to compare the working memory of their chimps with that of humans. In the task, numbers are displayed on a screen for fractions of a second, before being covered by white squares. The subject is then required to touch the squares in correct…
neurophilosophy | December 1, 2007
Using sophisticated techniques to silence or activate specific neurons, researchers from Stanford University have established that a simple behaviour used by fruit fly larvae to evade attack from parasitic wasps is triggered by a type of sensory neuron that is similar to the neurons which respond to painful stimuli in mammals.
Although little is known about the somatosensory system of fruit flies, several lines of evidence have implicated sensory cells called multidendritic neurons as nociceptors (cells that are responsive to noxious chemical, mechanical or thermal stimuli).
First, with…
neurophilosophy | November 14, 2007
An individual ant is quite insignificant, but a large group of ants can do quite remarkable things. Likewise, neurons evolved to communicate with each other, and are quite useless except when connected to a network of other neurons.
I've always liked to use the ant colony as an anology for brain function. According to this article about swarm intelligence by Carl Zimmer, it may be more than just an anology:
By studying army ants -- as well as birds, fish, locusts and other swarming animals -- Dr. Couzin and his colleagues are starting to discover simple rules that allow swarms to work so…
neurophilosophy | October 28, 2007A new paper about the reproductive behaviour of the spiny anteater, to be published in the December issue of American Naturalist, makes for fascinating - if slightly disturbing - reading.
The spiny anteater (Tachyglossuss aculeatus) is a primitive mammal with an unusual four-headed penis. The animal is difficult to observe in the wild, and does not readily copulate when in captivity, so exactly how the male uses its penis was a mystery.
Stephen Johnston of the University of Queensland and his colleagues obtained a male spiny anteater which regularly produced erections when handled during…
neurophilosophy | October 11, 2007
Ants and aphids have a symbiotic (or mutually beneficial) relationship. The aphids provide the ants with a food-source - the sugar-rich honeydew they excrete when eating plants - and, in return, the ants protect the aphids from ladybirds and other insects that prey on them.
To ensure a constant supply of honeydew, some ant species cultivate large numbers of aphids, and prevent them from straying too far from the colony by biting and damaging, or even completely removing, their wings. The ants also secrete a chemical from their mandibles which inhibits wing development in juvenile aphids.…
neurophilosophy | October 5, 2007New Caledonian crows (Corvus moneduloides) have remarkable tool-using abilities that are at least as sophisticated as those of chimpanzees, if not more so. To date, however, such behaviours have only been observed in contrived experimental conditions.
Using newly-developed miniuatrized animal-borne video cameras, researchers have now filmed wild crows using tools. The footage they have obtained is the first to show the use of tools by crows in their natural habitat.
Used in combination with conventional radio telemetry, the tail-mounted cameras provided the researchers with detailed…
neurophilosophy | September 27, 2007
(Image credit: C. Franklin/ PLoS One)
In the first study of its kind, a team of Australian researchers have used satellite telemetry to show that crocodiles can navigate hundreds of kilometres to return to their home rivers after being moved.
Mark Read, of the Queensland Parks and Wildlife Service, and his colleagues captured three large male estuarine corocodiles (Crocodylus porosus) from the Nesbit and Wenlock Rivers in northern Queensland. The crocodiles were transported 56, 99 and 411 km by helicopter, and fitted with specially designed satellite transmitters (above) before being…
neurophilosophy | September 24, 2007
Echolocation - or biological sonar - can be thought of as an auditory imaging system that is used by organisms in environments where vision is ineffective. It involves the emission of vocalizations by the animal, and the detection of the echoes of those sounds, which are used to produce three-dimensional information about the environment.
Echolocating organisms understand the world largely via the interpretation of the acoustic reflections, and possess specialized neural circuitry that performs the computations necessary for the perceptual organization of auditory information. This…
neurophilosophy | September 19, 2007
(Image credit: Emmanouil Filippou / GreecePhotoBank/ Current Biology)
Giant hornets are the honeybee's arch enemy. They enter nests, kill the bees and take them home to feed their young. Before leaving the nest, the pioneer foraging hornet secretes a hormone which attracts its nestmates. Other hornets then congregate at the nest, and attack it en masse. In this way, several dozen hornets can wipe out a colony of tens of thousands of bees in a matter of hours.
Bees normally fend off predators by stinging them. But this doesn't work with hornets, because a bee's stinger cannot penetrate…
neurophilosophy | September 17, 2007The Boston Globe has a nice article about the cognitive abilities of birds, by Seed Magazine editor-at-large Jonah Lehrer.
There's a remarkable similarity between a passage from Jonah's article and something I wrote about the same subject. On page 2 of his article, Jonah writes:
For most of the 20th century, "bird brain" has been used as an insult. Noting the stark structural differences between human and bird brains, anatomists concluded that birds are essentially flying reptiles. Their minds were too tiny for thought. But in recent years, scientists have discovered that the bird brain…
neurophilosophy | September 12, 2007Researchers working in West Africa have observed male chimpanzees taking great risks in order to obtain cultivated fruit, which they then exchange with females, who often became more willing to mate as a consequence.
Kimberly Hockings, of the University of Stirling in Scotland, and her colleagues have spent the last two years observing the behaviour of a small community of chimps in part of the Republic of Guinea called Bossou.
Although the chimps were rarely observed exchanging wild plant foods, they were seen to exchange fruits grown by humans far more frequently. The behaviour therefore…
neurophilosophy | September 8, 2007Spiders make my skin crawl, but it's always amazed me that, despite being mechanical and grotesque, they produce silk, which is not only one of nature's finest materials, but also one of the lightest and strongest.
The creator of the fictional superhero Spiderman wasn't too far off the mark when he decided that the character would have the ability to spin webs from his hands, because it is now known at least one species of spider - the Costa Rican zebra tarantula (Aphonopelma seemanni) - can secrete silk from its feet.
Stanislav Gorb and his colleagues filmed the spiders as they crawled up…
neurophilosophy | September 7, 2007The Believer has an interview with primatologist Franz de Waal:
De Waal's research is no friend to human vanity. In the grand tradition of Galileo and Darwin, de Waal provokes those who seek to draw a clear line between human beings and everything else. But his message is an optimistic one. If human morality has deep roots in our evolutionary past, then we can expect it to be more resilient, less susceptible to the contingencies of history. Seeing morality in this light also undermines the view of human beings as inherently selfish--a view that de Waal terms "veneer theory." Morality,…
neurophilosophy | September 6, 2007
Scanning electron micrograph of the moray eel's secondary jaw, with highly recurved teeth. Scale bar= 500 micrometres. (Rita Mehta/ Nature)
In today's issue of Nature, evolutionary biologists from the University of California, Davis report that the moray eel (Muraena retifera) has a protractable jaw that it uses to grasp and swallow prey, in a manner that is reminiscent of the creatures in the Alien films.
Most bony fish feed by a suction mechanism. The suction-feeding abilities of morays are limited, so until now it was not known how they could swallow the large fish and cephalopods…
neurophilosophy | September 3, 2007
The question of how birds migrate long distances has long baffled researchers, and there are various hypotheses about which navigational cues birds use when migrating. Over the years, it has been suggested that migrating birds use smell, visual cues such as the position of the sun, the geomagnetic field, or a combination of these. It is, for example, known that induced magnetic fields and electrical storms disrupt the navigational abilities of homing pigeons, but exactly how the birds detect, perceive and interpret a magnetic field remains a mystery.
A recent study led by Todd Dennis, of…
neurophilosophy | August 31, 2007A fundamental question for neuroscientists is how the activity in neuronal circuits generates behaviour. The nematode worm Caenhorhabditis elegans is an excellent model organism for studying the neural basis of behaviour, because it is small, transparent, and has a simple nervous system consisting of only 302 neurons.
Typically, an organic glue is used to permanently immobilize the worm on an agar plate, and specific cells of the nervous system are stimulated with microelectrodes. This method has its limitations, however. As it is restricted, the worm's muscles and nervous system cannot…
neurophilosophy | August 28, 2007
(Fleur Champion de Crespigny)
Researchers at the University of Exeter have found that female bruchid beetles (Callosobruchus maculatus, above) mate when they are thirsty.
Evolutionary biologist Martin Edvardsson kept some female bruchids with, and others without, access to water. All the females were given the opportunity to mate with a new male every day.
In the journal Animal Behaviour, Edvardsson reports that those females without access to water mated more frequently - up to 40% more - than those with access to water. This leads him to conclude that female bruchid beetles mate in…
neurophilosophy | August 24, 2007 Zooillogix is the latest addition to ScienceBlogs.com. It's chock full of weird and wonderful stuff from the animal kingdom, like the Peter's elephant nose fish, which detects prey using electrical fields emitted from its chin.
neurophilosophy | August 9, 2007
(From the Gilbert Lab at the University of Texas)
This carpenter ant (genus Campanotus), and the bullet ant in the first film clip below (Paraponera clavata), have fallen victim to parasitic fungi of the genus Cordyceps, which manipulate the behaviour of their host in order to increase their own chances of reproducing.
The spores of the fungus attach themselves to the external surface of the ant, where they germinate. They then enter the ant's body through the tracheae (the tubes through which insects breathe), via holes in the exoskeleton called spiracles. Fine fungal filaments called…