Posts tagged animals
Articles and news from the latest research reports.
Singing mice (scotinomys teguina) are not your average lab rats. Their fur is tawny brown instead of the common white albino strain; they hail from the tropical cloud forests in the mountains of Costa Rica; and, as their name hints, they use song to communicate.
University of Texas at Austin researcher Steven Phelps is examining these unconventional rodents to gain insights into the genes that contribute to the unique singing behavior—information that could help scientists understand and identify genes that affect language in humans.
The song of the singing mouse is a rapid-fire string of high-pitched chirps called trills mostly used by males in dominance displays and to attract mates. Up to 20 chirps are squeaked out per second, sounding similar to birdsong to untrained ears. But unlike birds, the mice generally stick to a song made up of only a single note.
“They sound kind of soft to human ears, but if you slow them down by about three-fold they are pretty dramatic," said Phelps.
'Selfish' DNA in animal mitochondria offers possible tool to study aging
Researchers at Oregon State University have discovered, for the first time in any animal species, a type of “selfish” mitochondrial DNA that is actually hurting the organism and lessening its chance to survive – and bears a strong similarity to some damage done to human cells as they age.
Such selfish mitochondrial DNA has been found before in plants, but not animals. In this case, the discovery was made almost by accident during some genetic research being done on a nematode, Caenorhabditis briggsae – a type of small roundworm.
“We weren’t even looking for this when we found it, at first we thought it must be a laboratory error,” said Dee Denver, an OSU associate professor of zoology. “Selfish DNA is not supposed to be found in animals. But it could turn out to be fairly important as a new genetic model to study the type of mitochondrial decay that is associated with human aging.”
Staff at the Seattle Children’s hospital have created the Cat Immersion Project — an audiovisual installation that brought thousands of virtual cats to a teenage cancer patient’s room.
16-year-old cancer patient Maga Barzallo Sockemtickem had spent seven months in the hospital in 2011 and had to return for more treatment in July this year. Because of her compromised immune system, she had to be isolated and was unable to see her beloved cat Merry.
The rat brain has served as an excellent model for elucidating the complex anatomy and physiological mechanisms of the human brain. As a result, a significant amount of information on brain diseases, such as dementia and Parkinson’s disease, has been determined from investigations using rat brains.
Predatory beetles can detect the unique alarm signal released by ants that are under attack by parasitic flies, and the beetles use those overheard conversations to guide their search for safe egg-laying sites on coffee bushes.
Full article: Predatory beetles eavesdrop on ants’ chemical conversations to find best egg-laying sites
Deep-sea squid removes its own arms to distract baffled predators
A species of deep sea squid can jettison its own bioluminescent arms to distract predators and attackers. Later, when the squid has safely escaped, it re-grows its lost limbs.
New statistical method provides way to analyze synchronized neural activity in animals
The synchronized electrical activity of multiple neurons gives rise to coordinated network activity. This cooperative activity is highly dynamic and widely thought to be critical for organization behavior and cognitive processes.
Current methods for the statistical analysis of synchronized activity can analyze pairs of cells or detect the existence of correlations between multiple neurons. However, there is no way of accurately determining specific groups of neurons that interact with each other, and how this activity changes with time.
How Low Can You Go? Physical Production Mechanism of Elephant Infrasonic Vocalizations
Elephants can communicate using sounds below the range of human hearing (“infrasounds” below 20 hertz). It is commonly speculated that these vocalizations are produced in the larynx, either by neurally controlled muscle twitching (as in cat purring) or by flow-induced self-sustained vibrations of the vocal folds (as in human speech and song). We used direct high-speed video observations of an excised elephant larynx to demonstrate flow-induced self-sustained vocal fold vibration in the absence of any neural signals, thus excluding the need for any “purring” mechanism. The observed physical principles of voice production apply to a wide variety of mammals, extending across a remarkably large range of fundamental frequencies and body sizes, spanning more than five orders of magnitude.
Read more here
Most creatures need a good sense of balance — especially tree-dwellers that swing among high branches. In mammals, the ability largely comes from three loop-shaped structures in the inner ear called semicircular canals; in most species, the size, shape, and arrangement of those loops (inset) is extremely consistent from one individual to another. But in three-toed sloths (such as Bradypus variegatus, the brown-throated three-toed sloth, pictured), many proportions of the semicircular canals are surprisingly variable from one sloth to another.
The overall variability is at least twice that seen in other species of mammals the team analyzed, researchers report online today in the Proceedings of the Royal Society B. That high degree of variation stems from the sloths’ languid lifestyle, the researchers suggest.
Sloths, which move extremely slowly when they move at all, don’t require the sense of balance that a swift, agile creature such as a primate needs. The finding supports one of Charles Darwin’s notions about evolution: If an organ isn’t crucial, variations in its structure or performance aren’t lost over time, keeping the potpourri in the population.
What Pleasure Looks Like in Babies, Primates and Rats
To decipher the brain circuits that underlie pleasure, neuroscientists often have to assess liking and disliking in nonverbal creatures. They do it by monitoring facial expressions and head and arm movements, such as those depicted in the video here. Licking the lips, for instance, indicates a food tasted delicious to in infant, whereas turning the head from side to side indicates “yuk.” In the video, the term “hedonic reactions” refers to pleasure.