Posts tagged animals
Articles and news from the latest research reports.
A glance at a star-nosed mole (Condylura cristata) is enough to convince most people that something very strange has evolved in the bogs and wetlands of North America. There’s nothing else on the planet quite like this little palm-sized mammal. Its nose is ringed by 22 fleshy appendages, called rays, which are engorged with blood and in a constant flurry of motion when the animal searches for food.
What is this star? How did it evolve and what is it for? What advantage would be worth sporting such an ungainly structure? To a neuroscientist interested in sensory systems, this kind of biological anomaly represents an irresistible mystery. I first began studying star-nosed moles in the early ’90s in an attempt to answer some of these basic questions. But I soon discovered that this unusual animal, like many other specialized species, could reveal general principles about how brains process and represent sensory information. In fact, star-nosed moles have been a gold mine for discoveries about brains and behavior in general—and an unending source of surprises. The most obvious place to start the investigation was with that bizarre star.
(Source: the-scientist.com)
In a study published in The American Naturalist, a group of scientists led by the Zoological Society of London (ZSL) have used a technique developed to study human consumer choices to investigate what influences a baboon’s foraging decisions. The technique, known as discrete choice modelling, has rarely been used before in animal behaviour research. It showed how baboons not only consider many social and non-social factors when making foraging decisions, but also how they change these factors depending on their habitat and their own social traits.
Helium reveals gibbon’s soprano skill
Apes are unlikely to become virtuosos at the opera house, but gibbons have naturally mastered some of the vocal techniques that human sopranos rely on, scientists in Japan report.
The research shows that, like humans, gibbons use a ‘source–filter’ mode of sound generation. The sound originates from the creatures’ vocal folds as a mixture of different harmonics, which are multiples of the frequency at which the vocal folds vibrate. The resonant frequencies of the vocal tract then determine which of these harmonics are projected. By altering the position of the mouth, lips and teeth, humans vary these resonant frequencies to make the different sounds required for speech.
The gibbon’s melodious calling bears many similarities to the techniques of human singers. Like professional sopranos, gibbons tune the resonant frequency of their vocal tract to the pitch frequency generated by the vocal folds to amplify the sound. Acoustic physicist Joe Wolfe of the University of New South Wales in Sydney, Australia, says that this type of “resonance tuning” is something that comes fairly easily to human singers and is key to their ability to project their voice over a loud orchestra.
A species of rat has been discovered that cannot gnaw or chew and represents a new step in rodent evolution. The shrew-like animal, Paucidentomys vermidax, has fang-like upper incisors which are useless for gnawing and no back teeth. It lives exclusively on earthworms which it sucks out of the ground at the foot of the jungle with its long snout.
(Source: Daily Mail)
Blindsight: Animals That See without Eyes
Recent insights into how animals see without eyes reveal that vision and light-detection are older and more widespread than biologists previously realized
To find out how mice use their high-resolution ganglion, a team from Harvard attached a tiny camera to a rat volunteer and then watched to see what sorts of things it focused on. Next, they played the video back directly onto the retinas of several test mice while simultaneously monitoring neural cell activity. In so doing, they found that the high-resolution cells sat mostly quiet, doing nothing.
When silhouettes of birds were projected overhead, the waiting ended as the ganglia sprang into action, interpreting every movement. This shows, the researchers say, that the high-resolution neuron groups in mice retinas serve not as interpreters of everyday life, but as highly specific predator detectors. More specifically they found the nerves reacted when the birds were in their center of view, meaning close and ready to snatch them up. Sadly, they also found that the nerves quit firing once the birds came close enough, indicating the mice were doomed.
In a new study, scientists at the Wisconsin Institute for Discovery (WID) at UW-Madison develop a computational approach to determine whether individuals behave predictably. With data from previous fights, the team looked at how much memory individuals in the group would need to make predictions themselves. The analysis proposes a novel estimate of “cognitive burden,” or the minimal amount of information an organism needs to remember to make a prediction.
The research draws from a concept called “sparse coding,” or the brain’s tendency to use fewer visual details and a small number of neurons to stow an image or scene. Previous studies support the idea that neurons in the brain react to a few large details such as the lines, edges and orientations within images rather than many smaller details.
"So what you get is a model where you have to remember fewer things but you still get very high predictive power — that’s what we’re interested in," says Bryan Daniels, a WID researcher who led the study.
According to new research, meerkats enhance their intelligence through nine different social and asocial mechanisms. What really makes these animals stand out is their intelligent coordinated behaviour, which rivals that of chimps, baboons, dolphins and even humans in its complexity and efficiency.
A team led by William Hoppitt of the University of St. Andrews presented wild meerkats with a novel foraging task to investigate the animal’s learning mechanisms. ‘The model deals with the rate at which individuals interact with the task, solve the task once they are interacting with it, or give up on the task when they are manipulating it,’ said Hoppitt.
They found that the meerkats engaged in a wide variety of social and asocial behaviours to learn to solve the task, and that in general the social factors helped draw the meerkats into the task, while the asocial processes helped them actually solve the task.
The model may also be more broadly applicable and can be used to investigate the relationship between social learning mechanisms and so-called ‘behavioural traditions’ that together can constitute a culture.
The Cambridge Declaration on Consciousness
We declare the following: “The absence of a neocortex does not appear to preclude an organism from experiencing affective states. Convergent evidence indicates that non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Nonhuman animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.”
Sheep Brain Dissection: The Anatomy of Memory
By dissecting the brain of a sheep -an animal in which brain structure and function are similar to our own- we can see where memory processes take place. Throughout our lives, our memories are constantly being formulated, accessed, and filtered by the brain. Fleeting electrochemical connections made between brain cells help us remember the thoughts, skills, experiences and knowledge that make each of us unique.