There is a scene in the animated blockbuster “Finding Nemo” when a school of fish makes a rapid string of complicated patterns–an arrow, a portrait of young Nemo and other intricate designs. While the detailed shapes might be a bit outlandish for fish to form, the premise isn’t far off. But how does a school of fish or a flock of birds know how to move from one configuration to another and then reorganize as a unit, without knowing what the entire group is doing?
New research by University of Alberta scientists shows that one movement started by a single individual ripples through the entire group–a finding that helps unravel the mystery that has plagued scientists for years.
A new “black smoker” — an undersea mineral chimney emitting hot, iron-darkened water that attracts unusual marine life — has been discovered at about 8,500 feet underwater by an expedition currently exploring a section of volcanic ridge along the Pacific Ocean floor off Costa Rica.
An infestation of predator starfish is decimating large tracts of coral reef throughout the Philippines. The spiny and toxic crown-of-thorns starfish are voracious predators that can wipe out large areas of coral; an individual can consume up to 6 square metres of living reef per year. Outbreaks of the species often occur when ocean temperatures and nutrient levels increase. Crown-of-thorns starfish have long spines and are capable of severe stings. Contact will almost surely inflict severe swelling, pain and nausea that can last for hours or days.
Whiskers provide a mouse with essential information to negotiate a burrow or detect movement that could signal a predator’s presence. These stiff hairs relay sensory input to the brain, which shapes neuronal activity. In a first, studies of this system by Carnegie Mellon scientists show just how well a mouse brain can compensate when limited to sensing the world through one whisker. Published April 4 in the Journal of Neuroscience, the results should help shape future studies of sensory deprivation that results from stroke or traumatic brain injury, say the authors.
Climate change could trigger “boom and bust” population cycles that make animal species more vulnerable to extinction. , according to Christopher C. Wilmers, an assistant professor of environmental studies at the University of California, Santa Cruz. Favorable environmental conditions that produce abundant supplies of food and stimulate population booms appear to set the stage for population crashes that occur when several “good years” in a row are followed by a bad year. “It’s almost paradoxical, because you’d think a large population would be better off, but it turns out they’re more vulnerable to a drop in resources,” says Wilmers.
Ancient aquatic amphibians developed the ability to feed on land before completing the transition to terrestrial life, researchers from Harvard University report this week in the Proceedings of the National Academy of Sciences. Their work is based on analysis of the skulls of the first amphibians, which arose 375 million years ago, and their fish ancestors. The shapes of the junctions between adjacent skull bones — termed “sutures” — in the tops of these fish and amphibian skulls reveal how these extinct animals captured prey, say authors Molly J. Markey and Charles R. Marshall.
Despite great progress over the past decade, the evolutionary history of placental mammals remains controversial. While a consensus is emerging on the topology of the evolutionary tree, although with occasional disagreement, divergence times remain uncertain. The age of earlier nodes and in particular the root, remain especially uncertain in the absence of definitive placental fossils deeper into the Cretaceous. Both paleontological and morphological studies suggest that the radiation of placental orders and super orders occurred close to the Cretaceous–Tertiary (K–T) boundary about 65 million years ago (mya). In contrast, molecular studies have suggested markedly older origins for many superordinal groups and that some extant orders diversified before the K–T boundary.
A team of researchers has found a simple and unique way to considerably reduce stress levels and increase the welfare of monkeys living in a popular zoo. The study, carried out by Durham University with Chester Zoo, found that planting a metre-wide barrier of tropical shrubs between the monkeys’ glass-fronted enclosures and the visitors’ viewing platforms reduced the animals’ stress-related behaviour by more than half.
Electronic mosquito repellents — buzzing devices marketed to prevent malaria — don’t prevent bites and therefore don’t prevent disease transmission, according to a new review of studies. “EMRs should not be manufactured, advertised or used for mosquito bite and malaria prevention, as they do not do so,” said lead author A. Ali Enayati, Ph.D., lecturer in medical entomology at the Mazandaran University of Medical Sciences in Sari, Iran.