Brains Not Beaks Help Birds Navigate.
A theory that birds sense the magnetic poles by using an iron-based chemical in their beaks was put to rest with a new and convincing study. As reported by the New York Times, two researchers have identified individual neurons in the brains of pigeons, each of which is able to respond to a particular direction of the earth’s magnetism. The researchers made their discovery by artificially creating magnetic fields in the laboratory. According to the new study, certain cells in a bird’s brain can sense and record details about the earth’s magnetic poles. Once the information is received by these neurons, it is likely stored and then compared to a map that birds “memorize,” probably by storing the mapping information in their brains’ hippocampus, just as humans do.
NYC Bee Licks Rather Than Stings.
Quick: how many bees are native to New York City? Surprisingly, at least 250 individual bee species inhabit NYC, with more being discovered all the time. One recently identified species has a particular liking for New Yorkers … especially sweaty ones. This bee species, named Lasioglossum gotham, does not sting but instead seeks out people and licks the sweat off their exposed skin. Apparently, the species enjoys a salty diet and there are plenty of walking salt licks on the streets of the city.
More at Daily Mail.
Human Evolution Continues.
Think of yourself as a fully evolved species? Think again. New research suggests that humans, just like other species, are still evolving. Indeed, although it would seem that our development of an agrarian culture would interfere with the normal evolutionary processes, that does not appear to be the case. Researchers studying records and fossils dating back thousands of years have determined that evolution is still unfolding in the human species, regardless of our own efforts to influence and control our destiny. For example, the human brain has been shrinking for thousands of years and human fertility rates, across all socio-economic strata, show variations similar to those of other species.
More at Huffington Post.
A lone dolphin has been living in the shallow waters off Huntington Beach California. When Marine Animal Reserve personnel attempted to guide the dolphin back into open waters, it was attacked and driven back into the shallows by a nearby group of fellow dolphins. To explain this behavior, and the general aggressiveness of dolphins toward each other, a theory of dolphin bullying has been proposed. However, this theory was denounced by Peter Kelly, an expert in dolphin behavior who doubted that bullying was involved and suggested that the aggressive behavior meant that “the dolphin’s peers were reacting to its strange behavior and unwilling to leave without their companion.”
More at Global Animal.
Dolphins Team Up With Fishermen.
In the coastal waters off Laguna, Brazil, fishermen and dolphins have formed an unspoken alliance. The dolphins have learned on their own that if they herd fish into the nets of waiting fishermen, they will get a cut of the bounty. Even though no effort was made to teach the dolphins this cooperative behavior, the participating individuals regularly herd fish and even signal the fishermen by slapping their tails on the water surface when it’s time to throw their nets. No doubt, this behavior will be passed on by the fishermen to their offspring, but scientists also expect that the dolphins’ behavior will be absorbed and adopted by their offspring as well.
More at Discovery.
A New Old Cookbook.
Want to try some old recipes — that is, really old recipes? A Culinary Journey Through Time is a new book that collects them. The authors, three Danish archaeologists, did extensive research based on what people cooked from the Stone Age to the Middle Ages. They compiled the recipes, which, with considerable effort in some cases, can be duplicated today. Bon Appetite.
More at New Scientist.
New Thinking on the Permian Extinction.
A New York Times article sheds some new light on an old problem. What factors led to the Permian extinction about 250 million years ago? Of the five major extinction events documented on earth, the Permian was the most severe in that it wiped out some 95% of all species of life. Research papers from Stanford and the University of California, Santa Cruz, focused on cellular level biology apparent from the fossil records. They conclude that species with vulnerable internal chemistry, such as corals, were most affected. That in turn suggests that excessive carbon dioxide entered the oceans and atmosphere, and that a resulting fatal acidification and warming of the oceans were the proximate causes of the extinctions.
Dino Demise More Complex Than Often Assumed.
Almost everyone has heard that the dinosaurs disappeared about 65 million years ago when an asteroid collided with the earth. Recent research, however, paints a much more nuanced picture of what really might have happened. Rather than a single punctuated catastrophic event, some dinosaur species had already been in decline for millions of years before the impact event. In this HuffPost science article, the author emphasizes that dinosaurs were not a monolithic group, that reduced species diversity appears to have affected some groups but not others, and that decreasing diversity was itself an indication of looming extinctions.
More at Huffington Post.
Long Lost Cousin.
A primitive, slow-moving fish known as a coelacanth that lived some 320 million years ago, was thought to be extinct. That is until a very much alive specimen turned up in a fishing net in 1938. Fossil evidence suggests that the coelacanth has not evolved very much in all that time and so it is often referred to as a “living fossil.” Now, scientists have combed through museum fossils and have identified the coelacanth’s cousin — dubbed rebellatrix. Interestingly, this extinct relation is marked by some distinct differences, especially in its forked, muscular tail, which suggests that, unlike its cousin, it was anything but a slow moving fish. It is also believed to have been a voracious hunter, unlike its milder extant cousin.
More at National Geographic.
Eye Size and Speed Correlated.
It appears that the faster an animal can move, at least on land, the larger its eyes are in proportion to its body size. Large eyes are needed to gather the complex information involved in running at high speed. An associate professor from the University of Texas at Austin was quoted, “This gives them better vision to avoid colliding with obstacles in their environment when they’re moving very quickly.”
More at Live Science.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.