| World's largest bat being hunted into extinction With a wingspan of more than 1.5 meters), the large flying fox ( Pteropus vampyrus ) is the world's largest bat. But that size hasn't helped it. In fact, the giant fruit bat has become a target for hunting, and so many of them are being killed every year that the species now faces possible extinction, according to a new study. [More] rss.sciam.com |
Rethinking "Hobbits": What They Mean for Human Evolution (preview) In 2004 a team of Australian and Indonesian scientists who had been excavating a cave called Liang Bua on the Indonesian island of Flores announced that they had unearthed something extraordinary: a partial skeleton of an adult human female who would have stood just over a meter tall and who had a brain a third as large as our own. The specimen, known to scientists as LB1, quickly received a fanciful nickname--the hobbit, after writer J.R.R. Tolkien’s fictional creatures. The team proposed that LB1 and the other fragmentary remains they recovered represent a previously unknown human species, Homo floresiensis . Their best guess was that H. floresiensis was a descendant of H. erectus --the first species known to have colonized outside of Africa. The creature evolved its small size, they surmised, as a response to the limited resources available on its island home--a phenomenon that had previously been documented in other mammals, but never humans.The finding jolted the paleoanthropological community. Not only was H. floresiensis being held up as the first example of a human following the so-called island rule, but it also seemed to reverse a trend toward ever larger brain size over the course of human evolution. Furthermore, the same deposits in which the small-bodied, small-brained individuals were found also yielded stone tools for hunting and butchering animals, as well as remainders of fires for cooking them--rather advanced behaviors for a creature with a brain the size of a chimpanzee’s. And astonishingly, LB1 lived just 18,000 years ago--thousands of years after our other late-surviving relatives, the Neandertals and H. erectus , disappeared [see “ The Littlest Human ,” by Kate Wong; Scientific American, February 2005]. [More] rss.sciam.com |
Scientists link flame retardants and reduced human fertility Women exposed to high levels of flame retardants take substantially longer to get pregnant, indicating for the first time that the widespread chemicals may affect human fertility, according to a study published Tuesday. [More] rss.sciam.com |
Celebrate Earth Day: Buy! Buy! Buy! A casual spin last night through the pile of ads inserted inside my local Sunday newspaper made it clear to me that the best possible thing we all can do this week to honor Earth is to shop till we drop. [More] rss.sciam.com |
Depression Drugs Affect Personality Friends and family of people with depression may feel that their loved one has been replaced by a gloomy doppelgänger. According to recent research, however, it may be the treatment of depression that actually causes personality changes in people with the disorder.Experts have long known that the placebo effect explains much of the mood lift patients report after going on antidepressants. This was the case in the new study, published in the journal Archives of General Psychiatry --patients with major depressive disorder who were given a placebo saw their symptoms im­prove about three quarters as much as those given paroxetine, an antidepressant also known as Paxil. But only the patients who took parox­etine displayed personality changes in two key areas of the widely used five-factor model of personality: they scored lower on neuroti­cism, the tendency to experience negative emotions such as guilt and anxiety, and they scored higher on extroversion, which includes traits such as talkativeness and assertiveness. [More] Antidepressant - Major depressive disorder - Placebo - Mental health - Health rss.sciam.com |